Hard-braking events as indicators of road segment crash risk(research.google) |
Hard-braking events as indicators of road segment crash risk(research.google) |
1. I'm on a race track or back road enjoying curves 2. Some asshole did something stupid in front of me.
I agree that hard braking is an accurate metric for road segment crash risk, but what I find upsetting is that insurance companies that use vehicle data treat /all/ hard braking equally. In reality, the risk is caused not by every person who hard brakes, but by the first person in a line of cars that hard brakes.
More on #2 above is that my observation has been MOST of the time, the braking was COMPLETELY unnecessary. Often the person hard braking that starts the chain has absolutely nothing in front of them to the horizon and is probably on their phone watching TikTok, suddenly looked up and realized they were driving and braked as a spooking reaction. This happens, observably, so often that there are active conspiracies on the Internet that the government hires people to drive like assholes to cause traffic. Obviously that's complete bunk, but my observation here is certainly not unique.
Rather than spying on everyone using our vehicle data to charge us ever more money (I've had zero at-fault accidents in nearly 30 years of driving, but my rates only go up), maybe we should enforce attentiveness on the road and start punishing those who are left-lane hogs (causing many lane changes, which are also risky), on their phone, or drunk. It's really obscene these days driving on American roads, it seems like everyone drives markedly worse since the pandemic /and/ enforcement has gone to nothing. The only time I see people get pulled over now is in speedtrap small towns.
In Britain at least we call it "braking distance" and you're supposed to leave 2 seconds at least between you and the person in front. Count it off a lamp post/sign etc.
In certain at-risk areas they use chevrons on the road and signs telling you to keep at least 2 chevrons between you and the car in front.
People definitely always get into my braking distance in slower moving traffic, so that happens here too of course. But when things are moving well I likely push the limit and am generally moving faster than most others: going by GPS speed vs speedo, pushing a little into the discretionary and unofficial +10% guidance etc. And weirdly enough I do this for safety and fuel economy.
I generally prefer to avoid other vehicles as much as possible in all situations. But I was a motorbike rider in my youth. Once a defensive driver...
From that perspective, following distance sounds way more like a gap I want to close up than braking distance does.
Indeed, that is the usual definition in the US for following distance. Along with a typical example of how to determine it for yourself.
We usually use the term braking distance to describe the distance that would be required to stop the car based on current conditions and speed. This is not necessarily going to be the same as the following distance.
Following distance is the rule that you should leave a 2 second gap in front of you. That is often less distance than the braking distance.
You should be always able to see that your braking distance is or will be clear, and that sets the maximum speed you should drive at as you approach areas with reduced visibility, like corners or the brow of a hill. You must learn braking distances for the driving test.
eventually got me to this: https://arxiv.org/abs/2409.15561 maybe interesting for someone whos privacy focused.
> It would have to be further than braking distance to be at least as safe?
Other way around. Following distance can be less, because the guy you are following cannot stop instantly unless he hits an immovable object or gets into a head-on crash. If he panic stops, then as long as your car performs similarly in braking you just need to have enough distance to allow for your own reaction time.
AFAIK braking distance for most cars is around 5 seconds at highway speed. Few people routinely set their following distance that long.
I was a bad driver. It would frequently beep at me to let me know that I had braked too hard. I was mystified. "What should I have done differently," I'd think, as I raged at the objective machine that judged me so.
The next time my brother came to visit, he called mom. "Oh, and presidentender is a good driver now." I didn't put the pieces together right away, but it turned out that the dongle had actually trained me, like a dog's shock collar.
The reason for my too-frequent hard-braking events wasn't speed, although that would be a contributing factor. It was a lack of appropriate following distance. Because I'd follow the drivers in front of me too closely I'd have to brake hard if they did... Or if they drive normally and happened to have a turn coming up.
Over the period I had the insurance spy box in my truck I learned without thinking about it to increase my following distance, which meant that riding with me as a passenger was more comfortable and it beeped less often. Of course since I'd been so naughty early during the evaluation they didn't decrease my rates, but I think the training probably did make me statistically less likely to crash.
Incredibly frustrating, and I've driven all over North America - there's practically no major city where this doesn't happen. If you're not maintaining a safe following distance on city/residential streets, that's a different matter.
I will never understand why this is so rage-inducing for people.
Changing lanes is a necessary part of navigating, even during busy traffic. People on an on-ramp will need to get in front of somebody. People needing to move back to the right because their exist is coming up will need to get in front of somebody.
Your lane is not a birth right. Let people merge.
> you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute.
This happens because literally everyone is tailgating each other so hard that the gap in front of you is the only gap that exists for people to change lanes to either get on or off the highway.
It does require patience to do this, because all aggressive drivers will use the space you provide. But ultimately the travel time difference in flowing traffic is negligible.
I recently pulled my travel trailer from OK to Charleston, SC and back. I never drive over 65 MPH for safety and MPG reasons. I always stay in the right hand, slow lane except if I have to take a left lane exit. Since I was always driving slower then everyone else, not once did I have to hard brake. Tailgating is a choice and a dangerous one.
I was never honked at, even by the crazy semi truck drivers.
1. In any amount of traffic above “a few cars” people will cut in front of me, sometimes two, negating the safe following distance. Regardless of speed.
2. If I have a safe following distance while waiting for someone to get over. (I e they’re going 60, I want to go 70), if I have my distance set at a safe following distance, people are much more likely to weave / pass on the right. (My theory would be that the distance I’m behind the person in front of them signals that I’m not going to accelerate / pass when the person gets over ).
Disclaimer: I don’t usually have to drive in any significant traffic, and when I do (Philly, New York City), I’m probably less likely to use the automatic features because the appropriate follow distance seems to increase the rage of drivers around me.
The only people who cut too close to me are driving recklessly.
That being said: If you're in the mode where people are constantly changing lanes in front of you, think a bit about how you're driving: On the freeway you're supposed to stay to the right except to pass, and you're expected to keep up with the flow of traffic. Are you going slow in the left lane? Are you driving too slow? Are you camping in the right lane by a busy interchange?
Having driven all over NA, and Europe, I find it more prevalent in NA. Less distance, more people in large pickups throwing their weight around to make someone move out of the way.
And a design of giant freeway interchanges that require shifting lanes.
E.g. on the 405 in CA. 7 lines going South from the Valley towards Santa Monica.
That's 7 lanes you need to cross if you're in the HOV lane.
Somebody on the radio said that "just set the adaptive cruise control to max distance and your windshield will last way longer". It does feel overprotective at times, especially in slow and dense traffic, but I think there's a nice point in general.
I just put adaptive cruise control on max distance and call it a day, gives me 4/5s to react, and also it starts beeping hard if intervention is required.
It has saved my bacon a couple of times.
To be sure, it's more mentally taxing to hold a tight gap, so it's not something you want to do all the time, but it's fine.
People only take your lane if you are in the fastest lane. If you are in any slower lane, people tend to jump in and then leave and I have no problem with people who do that.
You can also keep a gap in the fastest lane but you need to keep track of other cars on the road. You’ll observe that most cars rarely leave their lane. People who tend to leave their lane keep smaller gaps in front of them. Use that knowledge. There are many more factors than just that but if you start observing everyone drive, your little simulation in your head will start putting other drivers into buckets.
I had a slow realization that I could just let people jump in. My goal is to maintain a constant speed and never have to hit the brakes, and I can usually still do that regardless of whether people jump line.
But yes, the principle of it is incredibly aggravating ("that space is for safety, not YOU, green Acura!!!") but I actually kinda like the practice of trying to be zen about it. I mostly get through a long trip at the same rate :)
Usually if you maintain the slightly slower speed you had to maintain a safe following distance it doesn't matter, as the distance will either increase or they'll leave for another lane. You have to get used to drivers doing messy things in front of you, but at a safe distance. When doing this you are in fact helping the traffic becoming more fluid.
it's largely a problem in the left lanes, thats where drivers will bunch up most. the subjective feeling is mostly a reptile brain issue though, the feeling you're getting done over. driving is 90% id, sadly.
It’s not hard to do. It’s only frustrating if you let it be. It really barely slows you down at all.
For the sake of argument, assume you follow the "three second rule" and that the other driver is slightly aggressive and enters closer to the front of your safety buffer. You are now down to a two second safety buffer so rebuilding it back to three seconds costs you an extra second of travel time.
In practice this happens to me about a dozen times a day. It sometimes feels frustrating, as if each of these drivers is stealing another second I could have been playing with my kids! But ultimately it's worth spending the extra seconds to slightly increase the odds that I arrive home each day to play with them at all.
E.g.
- Switzerland and (somewhat surprisingly) UK: pretty good, people doing idiotic shit is rare enough that I'll usually comment on it if there's another person is in the car. If someone is riding my ass I'll make the effort to try and shake them off.
- Italy and Spain: horrifying, impossible to relax at all on the highway, having someone 2 car lengths off your rear bumper is the default condition.
- France and USA: somewhere in the middle where there are a lot of idiots but they are still the minority.
Subjectively, the USA feels much more sketchy because the rules are so much looser around overtaking.
This diagram changed how I think about following distance: https://entropicthoughts.com/keep-a-safe-following-distance
Just a few of these was enough that my "discount" was only a few dollars. I regret giving Progressive my driving data.
The only possible fix as a driver was to try to develop an intuition for spotting “stale” greens and start slowing down despite the green, anticipating the yellow.
I feel at least partially vindicated by the fact the lights in question eventually had their yellows extended.
What will happen if there's some oil spill or brake failure at the point you think you should break hard?
The incentives just don't line up.
It's probably the best single thing anyone can do to improve safety. It also reduces wear-and-tear on your car, and increases your fuel economy as a side benefit.
Why hasn't gamification of safe driving habits been built directly into the car itself before now?
It also shows how close you are to the car Infront in "car length" units with a nice big indicator and the adaptive cruse control will follow that distance mostly on its own between 30-100mph
(the irony of looking at a meter on the dash to duplicate a piece of information I should be very clearly seeing out of the windscreen was not lost on me, though)
I think it will also back down the cruise control (if set) if it detects that you are gaining on the car ahead. That might be MILs Toyota though.
I learned the "two second rule" in Driver's Education 45 years ago and generally follow that. Nothing more annoying than having the car behind you riding your bumper.
Instead of pretending to shift responsibility to the car, how about people do training every so often instead? Maybe every ten years for an hour or two.
The amount of work a young person has to do here to be able to obtain a "full license" takes literal years and multiple tests.
But then nothing for the rest of their life despite advances in technology (in and out of the car) and changed traffic conditions...
I'm all in for traction control and to some extent ABS, but braking hard and upsetting the car's balance when you don't need it is dangerous.
I am so glad it hasn't. Data point of one, but gamification now has the opposite effect on me: it's such a well-worn pattern that it just annoys me. It was great when it was novel. I wonder how many others feel the same but without sampling it's hard to know.
Unless it’s in Netherlands, where it’s 100%.
[0] https://www.npr.org/2018/06/12/619109741/clicker-training-fo...
- Road Accidents: "A driver caused this, let's determine who, and find them at fault."
- With Air Accidents: "The system caused this, let's determine which elements came together that ultimately lead to this event."
The first is essentially simplifying a complex series of events into something black and white. Easy to digest. We'll then keep doing it over and over again because we never changed the circumstances.
The second approach is holistic, for example even if the pilot made a mistake, why did they make a mistake, and what can we do to prevent that mistake (e.g. training, culture, etc)? But maybe other elements also played a part like mechanical, software, airport lightning, communications, etc.
I bet everyone reading this knows of a road near them that is an accident hotspot and I bet they can explain WHY it is. I certainly do/can, and I see cops with crashed cars there on a weekly basis. Zero changes have been made to the conditions.
I'm personally someone who is less worried about "privacy" for this sort of data. But I know lots of other people feel differently.
To me, this is a great example of the "greater good" for data sharing. But it is also a great example of responsible use of data.
So much so that I would argue that google (et al) should be compelled to make the data publicly available.
They have enough money, let's make society better.
I spend most of my time in California, have lived in SoCal and NorCal, and I spend a fair chunk of time driving around Virginia. My guess is that there's something fishy with the Virginia data being reported. Because if there is anyplace on earth with an insane number of controlled access roads, it's gotta be NVA/DC metro area (or the Tri-Border Area as I like to call it).
Also, they need to either update the caption for Figure 4, or move the plots to correspond with the caption. Clearly the Virginia data is on top (or the code is wrong, which seems exceedingly unlikely).
This research team used Google's first-party location data to identify San Jose's Interstate 880/US 101 interchange as a site with statistically extreme amounts of hard braking by Android Auto users.
But you don't need machine learning to know that... San Jose Mercury News readers voted that exact location as the worst interchange in the entire Bay Area in a 2018 reader poll [1]
It's not a lack of knowledge by Caltrans or Santa Clara County's congestion management agency that is keeping that interchange as-is. Rather, it's the physical constraints of a nearby airport (so no room for flyovers), a nearby river (so probably no tunneling), and surrounding private landowners and train tracks.
Leaving aside the specifics of the 880/101 interchange, the Google blog post suggests that they'll use this worst-case scenario on a limited access freeway to inform their future machine-learning analyses of other roads around the country, including ones where presumably there are also pedestrians and cyclists.
No doubt some state departments of transportation will line up to buy these new "insights" from Google (forgetting that they actually already buy similar products from TomTom, Inrix, StreetLight, et al.) [2]
While I genuinely see the value in data-informed decision making for transportation and urban planning, it's not a lack of data that's causing problems at this particular freeway intersection. This blog post is an underbaked advertisement.
[1] https://www.mercurynews.com/2018/04/13/101-880-ranks-as-bay-...
[2] https://www.tomtom.com/products/traffic-stats/ https://inrix.com/products/ai-traffic/ https://www.streetlightdata.com/traffic-planning/
Static hazards deserve physical signage and/or remediation.
In a similar way that Google Maps shows eco routes, it’d be fun for them to show “safest” routes which avoid areas with common crashes. (Not always possible, but valuable knowledge when it is.)
In unknown roads/highways I can predict hard bumps/gaps by seeing dark oil spots in the middle of each lane.
In theory, the most dangerous turns would probably have higher variance on hard braking data.
I'll never use one of these dongles, though, because I don't want my every move second-guessed. There's nothing _inherently_ dangerous about isolated hard braking or cornering or acceleration events. It all depends on context. Am I braking hard to avoid an obstacle or mistake by another driver? Is there someone behind me that's likely to rear-end me, or am I in the middle of a highway in the desert? Did I just replace my brake pads and I'm bedding in the new pads?
I don't want to have to worry about whether I've used up my invisible quota before the algorithm decides I should be moved into a more expensive insurance bracket.
I have to hope that the actuaries at the insurance company are well aware of that. Tuned correctly, the algorithm should not unfairly penalize you.
I am reminded of my mother-in-law. She has very few at fault accidents in her decades of driving. And yet she has been involved in a statistically unlikely number of major wrecks. She would say that she is a safe driver, because she is not found at fault. I think it more likely that she is an unsafe driver who creates situations where accidents are more likely to occur but in a way that will not peg her as the underlying cause. Her rates should go up. As should yours, if you are experiencing a very abnormal number of hard-braking events even though you can ascribe every one of them to something outside of your control. Because the implication is that something about your driving habit is increased risk.
Enough events should show clusters where potholes likely exist. You would think cities would love that kind of data.
"A 1974 study by Hall and Dickinson showed that speed differences contributed to crashes, primarily rear end and lane change collisions"
Hall, J. W. and L. V. Dickinson. An Operational Evaluation of Truck Speeds on Interstate Highways, Department of Civil Engineering, University of Maryland, February, 1974.
PDF download: https://iase-pub.org/ojs/SERJ/article/download/215/119/726
There's even no need to get the real names! To anonymously load person's risk coefficient, it's enough to ask to log in using Google account when buying insurance.
A negative binomial regression fit on observational data cannot establish that a statistical relationship is causal.
That's not gonna be something Google would research, of course, due to next to no alignment with their interests.
Can the quantity and length of tire marks on tarmac be used as a proxy for HBEs?
While you're at it, give me an option to avoid unprotected left turns and to avoid making a left turn across a busy road where cross traffic does not stop. (But only during heavy traffic; it's fine when nobody is on the road.) Not only are these more dangerous, they're also more stressful and they also introduce annoying variation into my travel time.
Also, a bad driver mis-breaking trips the cars behind into breaking too, which multiplies the energy waste and may also cause accidents through fatigue.
Mare experienced drivers will give you more leeway to avoid tapping the brakes with you, or simply go for a staring overtake.
Now she still has the machine, still follows too closely, and still breaks too hard in her new car...
Good it worked for you though!
No smooth maintaining of speed and nice passes as able without slowing down.
Surprisingly, his accidents have mostly seemed to involve gas pumps, barriers, and other obstacles at low speed.
This always stuck with me
Not in my case. I keep plenty of following distance, 9 times out of 10 my hard braking is because some idiot cuts into that following distance and brake-checks me.
Best trick for managing this is to "drive through" the car in front of you. That is, judge your following distance based not on the car in front of you, but on the car in front of THEM.
And you don't have to "drive through" all the way down the road - it only takes one car/one level of abstraction for this approach to yield really great benefits, try it if you don't believe me.
She said the only time that the data and the rates do not match is after an accident. After an accident, the rates go up, however drivers are more careful and are statistically less likely to have an accident.
I remember being too aggressive when I got to the Bay Area, and learning how nice it was to be let into the lane I needed to avoid being forced on a 5mi U-turn. When visiting back home I was too nice and people told me so.
I've reached a balance. Aggressive enough not to be taken advantage of, but being nice to drivers in need, specially when it doesn't really change things for me, like when letting a driver in costs me nothing because of how bad traffic is.
Although I keep a varying follow distance, if there is an open lane immediately adjacent to me, I don't care if i'm tailing someone a bit, but if I'm boxed then you better believe it's 6+ car distance.
This perfectly illustrates this broken mental model that leads to endless frustration.
Unless you put the car in reverse, you are still making forward progress. If someone merges in front of you at 30mph then you traveled hundreds of feet towards your destination in the time it took them to do that. Chill out.
Why was their license not canceled beforehand?
Did they not get caught? If so, why? Likely other drivers have noticed the bad driving behavior. If so, why did they not report it? If they did report it, did the reports get ignored? Is there even a system and process in place for such reporting?
If they got caught, was there hesitation to revoke their license? If so, why? A potential factor would be driving in an area where you have to drive to get anywhere, which is common in the US. Why has it not been addressed that you have to drive, even if your driving habits are bad?
If bad driving behavior is too hard to punish, why? If regulations do not allow adequate punishment of bad driving behavior, why have these regulations not been changed? If evidence is missing, what evidence would that be, and how could it be collected?
If the driver was drunk, what would have been the alternative to driving? Is there adequate public transportation for drunks to get home? "adequate" depends on the drinking culture in the area where that happened.
If the driver was untrained, why were they allowed to drive? You wrote about canceling their license, so they did get a license. How was that possible without training? Does the process for handing out licenses have to be changed? Is frequent re-training necessary (more data is needed for that; if that data isn't avilable, why not?)
Obligatory link to the CAST handbook in case you want to follow that line of thinking: http://sunnyday.mit.edu/CAST-Handbook.pdf
"Crash" not "accident":
What I would really like in a car is not only my current speed, but the relative speed to the car ahead of me. Given my car has cameras and other sensors for cruise control and other features this ought to already be possible.
This is the natural response of tapping the brakes for any slowdown: people naturally over compensating and chain reactions happening behind them. This video shows how stop and go traffic forms and snowballs with no real impetus beyond mis estimated follow distance.
I always pull away at the same speed as the car in front of me and maintain the same distance as when we were stopped. It is very easy to do and completely eliminates traffic build up if multiple people do it at the same time.
This is the same reason that we have amber lights on traffic lights, so that the drivers have time to get into gear and start pulling away so that when the light goes green they are imediately travelling through it, causing no excess traffic build up at the lights. Again unfortunately people dont concentrate when they are stopped at lights and so you have the situation where they see the light go green and then proceed to start changing into gear and remove the handbrake. By the time they are moving through the green light, they have already taken 10-20 seconds of green light time, eating well into the time alotted for cars to be travelling across the junction.
The only thing which will solve this is driverless cars, meaning that the cars can all talk to each other and move at the same time like a chain. I welcome this advancement to elimante human error in driving and get rid of traffic jams for good.
If drivers are using a 2 second following distance, commonly taught in driving school, then max throughput is simply
1 car / 2 sec
This assumption is untrue at very low speeds, particularly when it takes longer than 2 seconds for a car to pass a point. For instance if we assume cars are 4m long, then with an interval of 2 seconds the cars would be touching at 4.47mph
The assumption is also untrue at very high speeds. You'll want a larger gap. That's partly because at such high speeds the ability of a vehicle to decelerate differs - if a vehicle with good brakes does an emergency stop and the car behind it has a respectable 2 second gap but has worse brakes then they can end up colliding. It's also partly because a 2 second gap at very high speeds means the car in front is further away, and that can cause a greater delay before the driver realises what is happening. As a third reason a greater margin needs to be used at very high speeds simply because the consequences of a crash are that much greater and should therefore be avoided even more than at lower speeds.
Therefore there is a kind of U-shaped curve in the "safe" following interval, and consequently a speed at which safe throughput is maximised.
That's why variable speed limits have been introduced in various places. For instance, in the UK which normally has a 70mph speed limit on motorways, in very high traffic conditions this can be lowered using electronic signs to increase the safe throughput of the road. It's commonly reduced to 50mph, though it does get lowered further in sections approaching a queue of vehicles that has actually stopped.
There's also the issue of speed oscillations. With a high speed limit and vehicles following too closely, a little variation in speed in one vehicle can turn into a larger variation in the following vehicles, causing a backwards-travelling wave of braking (sometimes to an absolute halt) and speeding up again. Lowering the speed limit reduces this.
That postulate breaks down as soon as you move away from a laminar traffic assumption and include distracted drivers, lane changes, and weather influences. Which is why the wave theory model is important to understand the propagation of perturbations and their effect on maximum throughput.
> The throughput of a (full, i.e. rush-hour) road has nothing to do with speeds of people driving, and everything to do with following distance.
And yet, in the limit case of a bumper-to-bumper situation (or, in fluid dynamics parlance, an incompressible flow), the variable determining the change in mass flow-rate is the velocity of the medium. Mimetically, we could also look at ants. To ease congestion in a bumper-to-bumper situation, they accelerate.
Also you then just leave a bigger gap in front of you for somebody to jump into, forcing you to break more and go further back to maintain your distance. This in turn just winds up the drivers behind you who end up overtaking you. All this chaos becasue you think you are helping by 'reducing compression'.
In heavy traffic I much prefer to quickly catch the car in front up and then sit stationary with my engine off. Much more efficient and less polluting than spending the whole time with your ewngine on managing gaps and braking distances at low speeds.
Google is measuring where on the road most hard braking events happen.
Insurers measure who is having the most hard braking events.
The cause of hard braking isn’t mutually exclusive: bad driving or bad road design.
Have a look at a few dash cam accident videos [1]. There are many maladaptive patterns of behavior, but a frequent one that the average good driver can improve on is limiting speed on two occasions: when approaching a blind spot, and when passing stopped or slow traffic.
That second one gets lots of otherwise good drivers. They seem to think that by limiting their speed vs slow/stopped traffic they'd be encouraging people to dart in front of them. Which is somewhat true. But with limited speed, that's an avoidable or less injurious accident. By gunning it past stopped traffic, you make the accident unavoidable and more serious.
Most people have near zero defensive driving skill, and view someone pulling out in front of them as "nothing I could have done", when the dashcam shows the offending driver showed 5 signs of pulling out ages before the accident occurred.
It’s this obnoxious audio warning that tells me I had a hard breaking and it’s 9/10 because I stopped at a red light that I would not have made on yellow. And then it sends me tips and reminders about reducing hard breaking events and it’s annoying. I know they have done the analysis but it detects moderate hard breaking which is frustrating. One of those things that I am sure in net is positive but perhaps slices of the population it does not benefit.
Has this been studied in isolation? Many of the tools that notify upon hard braking also are used to impose financial penalties for doing so... I suspect people may be reacting to the financial incentives.
There is a minor financial aspect (price of fuel), but I’m far more interested in seeing if I can get a better “green score” at the end of the drive.
of course if they change such that they don't break hard when needed that is bad, but if the change such that they don't need to break hard in the first place because they slow down in places that are dangerious that is the point.
Is it that hard braking events are broadly indicative of surprises of lots of sorts, and so it happens that the only way to eliminate them all is to develop a full range of defensive driving habits?
More Goodhart's Law or Serenity Prayer?
Of apparent surprises to the driver. And since actual, factual surprises are extremely rare, if a driver is regularly being surprised, they're a bad driver.
It’s still out of the norm braking for my style of driver but from what I see on the road, people drive aggressively like this. Especially in the US.
... How do people not notice that they are braking hard?
From the article:
"Our analysis of road segments in California and Virginia revealed that the number of segments with observed HBEs was 18 times greater than those with reported crashes. While crash data is notoriously sparse — requiring years to observe a single event on some local roads — HBEs provide a continuous stream of data, effectively filling the gaps in the safety map."
So we don't have to wait until an accident actually occurs before we can identify unsafe roads and improve them.
I'd love to see them incorporate visual detection of vehicle crash debris as well. There are two intersections in my area that consistently have crash debris like broken window glass and broken plastic parts and license plates from crashes. I know they are dangerous, but I don't know if autonomous vehicles also know that they are dangerous.
Google/Apple probably collect a massively larger amount of data than those other companies, putting those other companies at a risk of losing future revenue.
Between Google and Apple pretty much every car in the US is monitored.
Where Google/Apple's coverage is quite valuable is for near-real-time speeds for atypical events -- say like yesterday's Super Bowl. But that's not what this blog post is about -- this post is about a well-established pattern that can be identified with historical datasets.
All that to say that vendors sell a wide variety of data products to transportation planners, but just because Google is now entering this niche market doesn't mean they'll be "the best" or even realize what their strengths are.
>Also, crashes are statistically rare events on arterial and local roads, so it can take years to accumulate sufficient data to establish a valid safety profile for a specific road segment.
That is exactly what this article is about.
> It's not a lack of knowledge by Caltrans or Santa Clara County's congestion management agency that is keeping that interchange as-is. Rather, it's the physical constraints of a nearby airport (so no room for flyovers), a nearby river (so probably no tunneling), and surrounding private landowners and train tracks.
The most recent budget estimate is $1bn for any changes to this interchange
The 401 is my favourite with eighteen lanes, four for the inner express lanes, and five for the collector lanes.
https://en.wikipedia.org/wiki/Ontario_Highway_401#/media/Fil...
1) Maintain a safe distances so you touch the brake as little as possible
2) Follow so close to the other car that you draft behind them (not recommended!)
Calling that person an idiot for your misunderstanding is not cool.
Obviously the calculus changes at rush hour when the exit ramp (and highway) begin to back up. And in those cases, yes, of course the correct answer is to slow down before the ramp, even if it means impeding traffic. (Or take the next exit.)
Just for fun, there's also a very short entrance ramp onto a 65mph highway in this city, which requires you to accelerate uphill from a stop sign with a very limited runway (~200 ft.) This entrance has been responsible for far more accidents and crashes than the exit I initially described.
Indeed, when someone changes lanes in front of me, I gently let off the accelerator, but as someone else noticed, that can enrage drivers behind me (I don't take it personally), and I'm definitely traveling fast enough to remain in the middle lanes.
I looked up an image catalog, and it seems that if an Acura's going to be green, it is likely to be an NS-X, which are fairly exotic as Acuras go.
I owned a black Integra for a while. If any had been green in those days, I would've definitely noticed! And, I definitely would've yielded the right-of-way to them, just so I could gawk and stare!
When the characteristics meet (when the lines overlap), you get a shock wave. Or, in the current context, a traffic collision.
However purposely making the cars behind you break more and causing more compression further back just so that you can avoid the compression in front of you is madness.
What? Your travel time does not get longer, and if the traffic is merely slow then this "leaving your engine running for more of the time" is nonsense. Even if it's stop and go and you have a car that kills the engine every time you come to a dead stop, that will use more gas because you're making inefficient use of the electrical system (charging and discharging the battery more than you should have to).
> Also you then just leave a bigger gap in front of you for somebody to jump into,
Sure, so as earlier you have to pay attention and not allow that.
> In heavy traffic I much prefer to quickly catch the car in front up and then sit stationary with my engine off. Much more efficient
Doubt.
And besides doubting your claim about efficiency, you're doing exactly that which most helps the pressure wave endure, and thus you're causing more delays for more people, and more people to have to brake hard, and more engine stop/start cycles, all of which means more pollution overall not less, etc.
You really have to think systemically.
Yeah, if you want to do that, it would be helpful to know whether a financial incentive is required for the effect or not.
Example: open space on either side of the road, tends to encourage people to drive faster.
Closing that space (whether by buildings, shrubbery, etc ) will slow the speed.
But I will say there are also “obvious” bad designs - the rare far to short on ramp to merge, where drivers don’t understand how to adjust.
Or the one I most frequently encounter are “blind spots” created by the speed of an intersecting road, where a mirror may be attached to a pole / tree, or a sign reminding people to look left right left, or even instructing where cars should be beyond for a safe pull out.
I know of one intersection near me that both has markers on the road(don’t pull out if cars are at or beyond this marker), and a reminder about looking, but still has a high frequency of accidents.
In the rural case, the offramp will branch off first and the on ramp will be after the overpass and the drivers taking each never meet.
In the space constrained case, theres one extra lane that serves both, where the drivers taking the on-ramp cross paths with those taking the off ramp. This configuration is absolutely cursed!
I also think some of the car sensors (Subaru especially) that are trying to make you safer are notoriously bad.
I also find the random “coffee break” notice on Subarus frustrating.
My personal examples: “eyes on the road” - triggered frequently by one pair of sunglasses I have, looking left to check blind spot, checking mirrors, etc.
“Hands on the steering wheel” - triggered occasionally on long drives when I have been giving input, but very light input.
I'd barely left the yard, certainly hadn't made it across town.
It went off when I actually did stop for a coffee, but went on again 15 minutes after I left the car park.
I have to say its various combinations of bings and bongs and beeps were about the most distracting thing I've ever experienced in a vehicle.
Maybe this would require an insurance company to have outsized market share in a specific area so they are the main beneficiary of the improvement
At the same time, passing on regular intercity road can have the risk reduced (up to a point) by making the passing quicker, by spending less time in the oncoming traffic lane ("aggressive passing"). It certainly does not help with comfort, though.
So perhaps your cousin is a very attentive driver who drives aggressively? That might still only make him an "average" driver (I've had such drivers almost get others in an accident in front of me), but I think it's a balance that needs to be struck, otherwise most would tune out and not be ready for emergencies.
At least I hope not.
More concrete example:
He will be going 65 mph in slow lane. Come up on a car. (Left lane empty). Slam on his brakes. Follow them at 50 mph for 1-3 minutes <1 car length.
Pass, flooring it, if he stays in the left lane he’ll keep going until he now tail gates a car in front of him- usually with large speed variances.
The amount of traffic on the road doesn’t matter. It can be 3 cars and he will drive this way.
I’m not talking about trying to drive through major city rush hour traffic.
What you are refering to is the well known phenomenon of traffic waves or phantom jams. The UK has all but eliminated them with variable speed limits without the need to make every leave half a mile gap between each car.
https://nationalhighways.co.uk/road-safety/variable-speed-li...
I welcome our future robot car overlords where all of these problems should in theory be greatly reduced or eliminated entirely.
I agree, a full network of self driving cars which can all move together in a chain will eliminate this problem. I just hope I live long enough to see it.
Really? All you have to do is lift your right foot very gently until you have the expected spacing again, no need to sudden changes of speed and if you have traffic aware cruise control it will be done for you. My old Tesla S does it pretty well. I keep it set to three second spacing and when someone cuts in front my car just gently slows down until the spacing is correct again; it doesn't brake unless the car that cuts in is very close.
If this doesn't happen to you, then you're probably driving like I do, and not leaving 3 seconds of follow distance like they teach in driver's ed.
Also perhaps I should have made it clear that I am in Europe where one is expected and required to drive in the outermost (rightmost except in UK and Ireland) lane unless overtaking so the only time anyone would 'cut in' between my car and the one in front is when they are entering a motorway.
If you want 4 sec gap at higher speeds that's fine, the formula is speed-independent for throughput, not speed-independent for following distance. If you want 4 seconds at high speed then use 4 sec instead of 2 sec (i.e. 1 car/ 4 sec)
>There's also the issue of speed oscillations. With a high speed limit and vehicles following too closely, a little variation in speed in one vehicle can turn into a larger variation in the following vehicles, causing a backwards-travelling wave of braking (sometimes to an absolute halt) and speeding up again. Lowering the speed limit reduces this.
"Lowering the speed limit reduces oscillations." Exactly, that is my whole point, that (again, locally analyzed) you can ignore the waves, and instead look only at the following distance of the slowest car in the lane, to determine throughput of the road behind that car. Your idea of "lowering the speed limit" to eliminate waves is the same net effect on throughput as observing that the throughput cannot exceed that given by the longest-following car on the road.
And from personal experience in some places, keeping such a buffer, in some traffic conditions would just literally be impossible. There are sometimes enough aggressive drivers such that they can just consume it faster than one would be able to create it. It is simply not always the case that you have sole power to create and keep the recommended buffer size (although very often it is and you can).
I keep a decent buffer whenever I am able, but at some point, you have to bow to road conditions.
Traffic moving with an approximately constant following distance is safer than traffic where one element is constantly traveling under speed to build up a following distance and is slowly filtering to the back as traffic comes upon and then moves around it. If the lane people are pulling into for passing is traveling substantially faster than the traffic that is being queued up behind to be passed then some amount of the people pulling out to pass are necessarily going to do so aggressively or within thinner than "perfect world" margins.
Every thing drivers on the road must perform carries some inherent risk. That a bunch of traffic that would have not gone around you will have done so means that many otherwise unnecessary merges or lane changes and then lane changes back will have happened. Each one of these represents an opportunity for things to go wrong above whatever the baseline is.
What I am saying is not groundbreaking or rocket science and the fact that I have to spell it out in detail to an adversarial audience speaks volumes about this audience and the volumes it speaks are not positive.
#trustmebro
#science
More like a few seconds.
Every car that merges in front of you only costs you their following distance. If the average following distance is 1 second, then you are simply 1 second slower than you'd have otherwise been. So unless this is happening continuously every 30 seconds on your 30 minute commute, you will lose less than a minute.
The "but if I kept reasonable following distance, people will keep merging in front of me and I'll lose time" excuse is pretty thin given this analysis.
And an insurance claim can easily eat 40 hours of time between the insurance companies, other lawyers, buying a new car, medical appointments and recovery. That's 19,200 minutes you won't get back, or about 52 years of driving 1 minute slower each day.
Slow is smooth and smooth is fast.
A slight increase in average speed really only makes a significant difference over long drives. (5 mph increase over a 10 hour drive can cut off 50 minutes).
Otherwise we are talking about small differences in efficiency.
(I would be very open to another opinion here.).
My opinions are formed by nearly ~2 million miles driven at this point, two different driving courses, and the motorcycle safety course.
One thing I truly think that’s overlooked is how reduced road noise in the vehicle cabin can both reduce driver fatigue, but also frustration in traffic.
Yes! I feel like I can't shout this loud enough. In addition to maintaining a safe driving distance, just leave a little earlier. The stuff I've seen people do in order to save 20 seconds boggles the mind.
Unfortunately, I think commuters fall into a gamification mindset. They're trying to set a new lap record each day, and you can see the results just by driving (or walking) during rush hour...
You can't really say that without knowing the starting speed, or alternatively the distance. All you can say is that a 5 mph increase over a 10 hour drive with get you 50 miles farther.
If you do a comparison of a 600 mile trip at 60 vs 55 you’re pretty close.
But yes, to be pedantic and more exact, you are spot on that it will get you 50 miles closer.
But in real world examples,
If you’re traveling 700 miles.
65 vs 70, 70 will reduce your time by 43 minutes.
So in certain scenarios, 5 mph difference must be able to save you 50 minutes ! ;)
(I do understand your point, and you’re correct. I’m just poking fun at it- my point with the mph difference is because 50 miles doesn’t have the same translation for most people at 50 minutes, but is a more accurate data approach. )
I can easily shave 10% off my commute by lane changing to avoid the lanes where turn lane traffic tends to back up into the travel lanes, ramp traffic and "problem people". I test the null hypothesis several times a month by carrying bulky topheavy cargo that precludes a bunch of lane changing without more effort than I want to put in.
I don't think there's much to be gained by simply lane changing to chase fleeting gaps in traffic. The wins and losses will probably mostly cancel out.
Unfortunately, sometimes over a 45 minute freeway commute, dropping back repeatedly means arriving 15 minutes or more later. Again, no big deal now, but it was somehow unacceptable when I was younger.
That drives me nuts. When you put x amount of force into the brake pedal, you should know you're going to get y amount of deceleration. Don't double the brake boost just because you decided it's an emergency due to some opaque criteria.
No, it's just breaking a bit too hard for you while the panel beeps and has scary red lights pop (that you'll have a hard time reading).
If you decide to swerve, the additional weight at the front will help you to initiate the turn, and good systems will then reduce the braking force at the right moment to give you the most traction when cornering.
First, the insurance company incurs costs just processing the claim. If things escalate with the other party, they may even incur legal and court costs.
Additionally, there are some costs that are incurred regardless of fault -- like personal injury protection.
Even defining "who was at fault" is a complicated situation. A lot of people presume that it is as simple as: whoever the police issues a citation to at the scene is 100% at fault. But that's not the way things actually work. The way liability is assigned depends on the state, but in a comparative negligence state you could be proportionately liable for as little as one percent of the fault of the accident. Maybe someone else ran a red light, you entered the intersection on green, and hit them. You could end up sharing some of the cost for that, if it is found that you could have avoided the accident but decided not to.
And even after all of this, if the other party runs out of money, doesn't have insurance, or runs away at the scene, your insurance company is stuck paying the costs under their uninsured/underinsurred motorist coverage.
This is very state dependent, if we are talking about legality.
In WA state, for example, there is no "flow of traffic" law or similar. The limit is the limit, and any excess of the speed limit is illegal regardless of what all other drivers are doing. So even if the right/slow lane is going 100MPH through the 70MPH zone, you are legally expected to still go 70.
Thankfully we do have laws against left lane camping, but I rarely see it enforced.
Are you sure? And by that I mean, are you sure there are states that don't work the way WA works?
This has nothing to do with the expectation that slower traffic stay in the rightmost lanes, which is what GP is addressing.
That's not true. Examples:
I once pulled out my local newspaper where local judges were petitioning to have speed limits raised because they were throwing out speeding tickets due to excessive fines. This was in Massachusetts, in the late 1990s or early 2000s, about a road in Shrewsbury near lake Quinsigamond. The context was that the speed limit was 25, traffic flowed at 40-45, and they would throw out tickets for people doing 50.
I was once pulled over in a Massachusetts tollbooth even though I was the slowest driver on the road. (2004, I90 westbound at the intersection of 128, when EZ Pass still had to go through actual tollbooths.) If I was given an actual ticket, I would have point-blank told the judge that I was going half the speed of everyone else and feared getting rear-ended; then the case would have been dismissed. (The cop also knew this, because he recognized me from traffic court and knew that I'd make him look like a fool for pulling over the slowest driver.)
As far as I can tell it's pure selfishness and competitiveness. Their desire isn't to cooperate and arrive it's to take from others for their own gain.
Also "Only pass in the left lane" only makes sense when the lanes aren't significantly full. The guy in the left lane wants to do 90mph but the average speed of traffic is <55mph. Should I move over just because I'm doing 55 (despite wanting to do 65) and they want to do 90? They can only do 90 if there's a cascading group of drivers in front of them who defer their own desires to the desire of the most aggressive. Seems obvious to me that moving over to let them pass is not the right move.
The main issue is highways and rural roads.
The main issue is highways and rural roads.
Fuck all of that.
Similarly, people often don't like it when insurers track and score their driving. However, this allows insurers to offer lower insurance fees to more people by _not_ offering lower insurance fees (or instead charging higher fees) to people that are driving in a risky manner. This does of course assume a competitive market for insurance but I think in most countries that's a reasonable assumption.
There's nothing fairer than user-pays, especially when users can choose to pay less by changing their behavior.
That's probably true in theory, but not in practice, given how high US credit interest rates are compared to European countries for instance.
> Without credit scores, fewer people would have access to credit.
Too many people having access to credit is exactly how we got the worst financial crisis of the century, so it's not really something to brag about… People talk about US public debt a lot, but private debt is even more worrisome.
If user pays is so fair why does anyone who could access credit or liquid assets in excess of their state's minimums have to pay hundreds to thousands per year for auto insurance?
Because you were towing a camper and "slow and in the right lane" fits people's mental model of how recreational/nonprofessional heavy traffic or otherwise "handicapped" vehicles ought to behave.
When you have problems is when you behave to a standard beneath what other people expect from whatever kind of traffic you are.
I don't want to live on this planet anymore.
Much of being a good driver is just awareness.
One time my light turns green, I don't go. As my wife asks what I'm waiting for, a pickup blows the light. We weren't the first car at that light, and years later she still talks about how there's no way I could know. Well, I didn't get us t-boned at 80 so I must have done something right.
I do both and I am constantly surprised at the lack of situational awareness of drivers when I’m a passenger in their cars.
I think truckers probably get the same thing too.
Also "Keep Two Chevrons Apart" is going to be the name of my specialist Citroën breaker's yard.
On the occasion when I am towing our travel trailer, it is really incredible how unsafe that makes other drivers act around me. They will jam themselves in front of me at all costs, with no consideration for physics.
I know you were probably writing tongue in cheek, but that is one of those "solutions" that doesn't stop bad actors and makes good actors more miserable than usual.
[1] SF drivers will get that.
Also, having two of the same type of accident twice in such a short time is so improbable, that I'm seriously doubting your friend. I'd say it's way more likely she braked too suddenly or has other bad driving habits that make such accidents more likely than that she got this unlucky.
That is true. If you're going 55 mph for 10 hours, you'll go 550 miles. Increase your speed to 60 mph, and you'll get there at 9 hours 10 minutes.
- Driving from Tahoe to SF where the limited lane visibility due to the slope and a slight twist made the system think I was going to hit the car I was overtaking (from the 2nd and left-most lane). This really felt dangerous since it activated mid-turn and messed with the car's balance.
- The other event was a roundabout where a car yielding to get in behind plants jump-scared the breaking system. At 10-15 mph or so the unexpected breaking wasn't dangerous though, worst-case scenario you get rear ended at low speeds.
Beyond that, overtakes where you slow down as you return to your lane may trip the system, but those cases are fair even though the following distance they intend is a bit too cautious. I reckon my Mom would be holding the roof with both hands if she was there, but my Dad & siblings unfazed.
I did find "normal" mode on the Model 3 was way too sensitive, but I set it to "late" and it's been fine ever since.
Setting the side mirrors based on the AAA method works for a lot of reasons, and it helps with this too. So does flipping the center mirror over to the dark side.
Out of sight, out of mind.
They can be elect to stay back there behaving however they want, or they can go around be however they need to be somewhere else.
If you just can't stand it anymore, then just hop off the highway. It can be a good opportunity to stop for some coffee or a soda. Or, you know: Just to get out of the car, stretch out the ol' legs, and taste that acrid city air, think about something or someone in the world that is beautiful for you, and chill down a second.
Or just go up one exit ramp and down the entrance ramp on the other side of the crossroad, if the intersection design allows this move to be made safely and conveniently.
They almost certainly won't follow. They'll instead be disappearing down the highway at warp speed the whole time you're doing this, and you'll probably never across them again in your entire life.
It only costs a few minutes. They may seem interminable, but they're few. The benefit is relief from the mounting agony of dealing with this aggressive driver that might otherwise stick with you the rest of the day and that's good for your brain health.
(And if they do follow after you give them every opportunity to not do that? It's not Hollywood or the national news and this actually doesn't happen much in the real world on an individual level, but: Call the police at 911 or 999 or 0118 999 881 999 119 725 3 or whatever it is, and get some help.)
So much of road etiquette boils down to leaving adequate space so others can maneuver around you. Trying to optimize your travel by destroying any gaps as soon as they appear actually has the opposite effect.
However, on the rare occasion I've found myself going slowly in the right lane, it's stunning how incompetent most people are at merging. It's like they don't even consider looking for an opening in traffic, matching the freeway speed, etc. They just lumber in front of you at 43mph, and maybe, if you're lucky, look in their mirrors after they've already caused you to slow for them.
Speed is a very dangerous thing when pulling any type of trailer and it always amazes me when I see a truck pulling one at break neck speeds and somehow thinking they can maneuver normally when someone causes a situation where they have to make a split second decision.
But even if 2 dozen people go around you and creep into that following space, you've been cost like 45 seconds at worst. Better not to play the game.
Sometimes I think it's just people's reflexive scarcity mindset that tells them "that spot must not be that desirable or someone would be in it."
Regarding the broader topic of hitting your brakes, I find that I can commute 20 miles in stop and go traffic and only tap my brakes a couple of times. Helps to pace yourself behind the car 3 cars ahead of you instead of the guy right in front of you.
Not a significant cost. But they sure as shit aren't getting what they think they're getting. Meaningfully farther ahead.
I now see it all as a risk assessment rather than as ritualistic combat.
Even if I do need to brake, speeding up more slowly also usually means I have more buffer time to slow down too.
You're just going to wind up being approximately the slowest person on the road, which is fine if you're constantly trying to go slower to build space but this means that a bunch of traffic that would have not gone around you will do so. This ups the danger vs a steady flow less all these lane changes because every "thing" other people do is an opportunity to do it badly.
Kinda ironic when you consider that TFA was about detecting dangerous merge situations in the data.
The article stuff definitely doesn't.
Driving with bad drivers should incentivize you to follow less closely and require less hard braking, not more.
There's a motte where some poor fellow is always maintaining the car-length-for-every-10-mph rule and yet keeps being passed inside that distance by innumerable bad drivers the fellow is surrounded by.
I pity that fellow.
He has an excuse.
He also isn't observably real in any of my 21 years of driving in Buffalo, Boston, and Los Angeles.
I feel harsh for saying this, I am only saying it because A) this subthread is specifically about there isn't an excuse B) this stuff involves our lives. Thus, this is an appropriate venue because the people in the venue know what to expect, and poking at someone's thoughts on it may help them immeasurably.
It's almost as if the purpose of the system is what it does.
At any rate, even if people are continuously going around you like water going around a rock in a stream, you only have to drive 2 mph slower than traffic to constantly rebuild your following distance from the infinite stream of cutoffs. But my experience is the majority of following distance is eaten up by people randomly slowing down, not cutting in.
The issue is not that I can’t rebuild the following distance, the point I’m trying to make is that even if I constantly rebuild the following distance it sets off a cascading effect.
I’m following at set speed, car cuts in front, hits brakes, I now slow down, car behind me slows down, I rebuild following distance and car perhaps 7-8-9 cars behind me repeats because at some point the cascade magnifies to a larger slowdown behind.
Can I mitigate this by manually letting my distance be closer for a time, and slowly easing to larger ? Yes.
But if I allow the car to do it automatically, it will increase the follow distance at a rate that causes a cascade in tight traffic.
Though - I do think with these discussions on HN- it does depend on where you’re driving.
My experiences are centered on East Coast, thinking of route 80, 81, 83, etc. or Philly / New York City.
The driving experience is radically different in California, Florida , or the mid west.
I would say when driving in California people seem to navigate traffic better. (SF, LA) then on drivers on 80/81/83. (Or perhaps it’s due to better designed roads ).
At 60 kph (16.7 m/s) 1 car distance (about 5 m) is less than one third of a second. Even 2.5 car lengths is less than a second. I use traffic aware cruise control on my Tesla set to the maximum separation which is about three seconds, so 50 m at 60 kph.
Three seconds separation is in fact the recommended following separation in most European countries and in Germany in particular 0.9 seconds or less can result in a hefty fine, see https://en.wikipedia.org/wiki/Two-second_rule
In the UK some stretches of motorway have chevrons marked on the road indicating the required spacing at the speed limit.
However - I will say most of the roads I’m on are 2 lanes of traffic. I will have to experiment and see if this doesn’t occur when there are 3 or 4 lanes.
One part of your post was about people passing on the right. People won't do that if you're in the rightmost lane.
What I will say is some of this may be the difference between manual driving - and automatic.
If I’m manually driving - where my follow distance fluctuates more due to speed / traffic - almost no one cuts in.
If I am driving where I’m using the vehicle to maintain a perfect set distance, people cut in.
Again, anecdotal
Sure, in absolute numbers. But..
In the US, highest deaths per 100M vehicle miles:
1.79 - Mississippi
1.73 - Arizona
1.72 - South Carolina
And the lowest:
0.56 - Massachusetts
0.70 - Minnesota
0.78 - New Jersey
Or, highest per 100,000 population:
25 - Mississippi
25 - Wyoming
21 - New Mexico
Lowest per 100,000:
4.9 - Massachusetts
5.7 - New York
6.5 - New Jersey
Maybe the average MS driver drives 3-5x as many miles as the average MA driver? I doubt it. Something else happening there.
https://www.iihs.org/research-areas/fatality-statistics/deta...
The majority of car collisions happen on urban roads where the majority of cars are.
The majority of fatal collisions occur on rural roads, where vehicles are travelling faster.
I live in the UK.
https://www.simplyquote.co.uk/insights/where-do-most-car-acc...
If my hypothetical cost over an N decade period is within a fraction of a percent of payouts in that time what do I gain by paying for insurance other than creating a principal-agent problem?
Almost nobody follows it, but that is what the rule is.
I’m car 2, waiting to pass car 1. (Who’s passing a car slowly ). I have safe following distance.
Car 3, passes me in the right lane, and then either follows car 1 closely, or, quickly passes them on the right. (Usually as they’re in the process of moving over, causing them to then swerve back).
I realize I communicated this in an absolutely abysmal fashion.
I live in the UK where highways majority used for inter city transport.
And a quick look at map of London and Birmingham suggests that it may very well be the case in the UK as well…
I'll get you started:
https://www.gov.uk/government/statistics/national-travel-sur...
It's relatively unknown for individuals because most people have no desire to lock up tens or hundreds of thousands of spare dollars just to avoid car insurance. As far as I'm aware it's primarily used by rich collectors who need to insure large collections that don't fit more traditional insurance profiles. Much more useful for businesses.
That's BS on it's face. Most states don't allow it or they restrict it to big business and government agencies.
>because most people have no desire to lock up tens or hundreds of thousands of spare dollars just to avoid car insurance.
Most people's money isn't making a return greater than what insurance would cost them.
Second, this completely ignores my point about credit. I can easily get hundreds of thousands of dollars in credit secured against my house or tens of thousands in unsecured credit (credit card). Why must I pay to keep the lights on at some insurance firm?
And I'm not particularly rich. If the numbers pencil out for me then surely they must pencil out for millions of people.
That's BS on it's face. Most states don't allow it or they restrict it to big business and government agencies.
Most people's money isn't making a return greater than what insurance would cost them.
Second, this completely ignores my point about credit.
States' interest here is in guaranteeing that there will always be a minimum amount of money to compensate victims, regardless of what other financial shenanigans you have going on in your life. That's not a standard that lines of credit and investment accounts meet. Self-insurance is simply a terrible option for most consumers, so no one does it.
Note that you _are_ legally required to pay your annual ACC levies, which fund no-fault cover for injuries. However that doesn't cover property damage.
The solution is just to stay out of Atlanta, or drive faster. I'm OK with that.
Not really sure where you were going with all this. Sounds like pretty extreme, weird behavior that you are advocating.
Advice for when someone is following closely in anger that summarizes to "try getting off the highway for a minute and if that fails call the cops." is suggesting you perform "extreme, weird behavior"? I don't understand your reaction at all.
The first weapon to be employed is a Middle Finger. If that proves ineffective, it's followed by a lugnut taken from a coffee can that I keep handy. If and when things get to that level, the person usually wises up quick and finds a new hobby. There are other tools available if the nutcase decides to escalate further.
No, in this case it was just people speeding along at 95 (in a 70) who were terribly offended at my dangerously slow driving, who wished to register their indignation as they flew by, momentarily held back but undeterred as they sped off to their Bright New Tomorrow. Message received, loud and clear.
Inb4 deaths per mile driven, I'd argue higher VMT in the U.S.A. only proves the point - too many cars being driven too much because of silly land use. High VMT is acutally a symptom of a dangerous mobility system as much as a cause.
I (an American) was on holiday and Switzerland and was explained the process of getting your license back if you lose it. It is a big disincentive to driving badly and putting yourself at risk of that, to be sure.
People don’t usually act erratically for no reason. Maybe they suddenly stop because they see a deer sprinting towards the road off in the distance, and the person behind them didn’t see it. There are tons of reasons that look like they “erratically stop”, which are actually genuine safe behavior that the other may not know about.
But now even when in a car, I retain that "I'm invisible" mentality, which makes me much more aware of what other drivers are doing, and much more skeptical of their ability to make good decisions. This has saved me several times.
please stop doing that geocrasher
One thing HPDE taught me is that most people under brake in dangerous situations because they simply don't know the limit of their vehicle nor the sensitivity range of the brake pedal.
The hard braking heuristic makes sense when estimating risk of road segments, but not as a proxy for driver competence.
I realize this may come off as victim blaming, but I feel you should have an obligation to not endanger yourself even if by the laws of the road you are technically in the right. I would rather get cut off by and idiot and be at my destination thirty seconds later than having to deal with car repairs even when it is legally speaking not my fault.
You are very unlikely to get stopped for either of those.
Another commented using an example of 8 and 9, but here it’s “9 you’re fine, 10 you’re mine”.
35 years without an accident on my record isn't because I'm a magnificent driver, it's because I always try to leave a way out for when something unexpected happens, because the unexpected _does_ happen.
The fact that some people may have the skill to drive more aggressively means nothing in the aggregate as far as insurance companies are concerned. If you are skilled enough to drive in that manner, you are skilled enough to avoid it as well. It's simply statistics.
Then use it? Mandate reaction speed tests or other driving mechanics competency evaluation (not road sign comprehension) and watch insurance margins explode.
The driver in my example did poorly and scored top marks in the heuristic.
On any modern car, just push it all the way and let ABS and stability control figure it out, and don't let the vibrating brake pedal spook you into releasing it. That's just ABS doing its thing.
Really though, getting a license is too easy in the USA. We really need to require some sort of car control course, including obstacle avoidance in the rain. Would be really nice too if it included an obstacle avoidance course in two cars: A huge SUV or pick-up truck and a more reasonably sized sedan. So many drivers think they need a huge vehicle to be safe while being completely unaware of how well smaller cars can likely avoid the crashes to begin with. Would probably get really expensive really quickly, though.
And Psychologists!
Reading the comments in this thread is quite amusing.
As a driver in India, i can tell you anything goes as long as you don't get into an accident (which may/may-not kill you) or get caught by the police.
No rules matter and the only goal is to "one-up" everybody else on the road and if they are trying to "one-up" you, then prevent it by any means possible. It is a "game of chicken" in its purest form; game theory in action. Rules are mere suggestions only followed by the meek and the weak.
You have no idea how invigorating it is to drive in India.
I was only briefly in India and did not drive while there, but the one rule that everyone adhered to was: communicate what you're doing by honking.
If you are stopped: honk to let people know.
If you are moving: honk to let people know.
If you are turning: honk to let people know.
If you are proceeding straight: honk to let people know.
If you are on a motorbike or in an autorickshaw: honk twice to let people know.
Etc.
Drive in India and you will understand mathematical concepts of Chance/Randomness/Probability/Non-determinism/Game Theory/etc. along with philosophical concepts of Fate/Destiny/Providence/etc. in so direct and visceral a manner that you will never forget the lessons. Sissified countries with rules and regulations for driving can never give you such direct knowledge.
Game Theory - https://en.wikipedia.org/wiki/Game_theory
Game of Chicken - https://en.wikipedia.org/wiki/Chicken_(game)
The game of chicken models two drivers, both headed for a single-lane bridge from opposite directions. The first to swerve away yields the bridge to the other. If neither player swerves, the result is a costly deadlock in the middle of the bridge or a potentially fatal head-on collision. It is presumed that the best thing for each driver is to stay straight while the other swerves (since the other is the "chicken" while a crash is avoided). Additionally, a crash is presumed to be the worst outcome for both players. This yields a situation where each player, in attempting to secure their best outcome, risks the worst.
How to learn One-upmanship/Gamesmanship:
The British author Stephen Potter actually wrote a manual on the practice of such games titled The Theory and Practice of Gamesmanship (or the Art of Winning Games without Actually Cheating) which sissies can study to become strong - https://en.wikipedia.org/wiki/Gamesmanship
For the even more sissified sissies who do not want to read a book, there is a documentary titled School for Scoundrels Or How to Win without Actually Cheating) which is very instructive - https://en.wikipedia.org/wiki/School_for_Scoundrels_(1960_fi...
Disclaimer: I am not responsible for the consequences if the above emboldens you to act in such a manner in your specific context.
So it's bad to be mad while driving, but there's a lot of lane changes that deserve the ire. (It's a tiny fraction of drivers that get really bad, but a less tiny fraction of lane changes.)
Yes, but the comment above was about society collectively making a decision, so that's the context I responded in.
And while it's relaxing to not worry about your own exact speed, I don't see how that lets you avoid stressing about the people that are lane-weaving. They're acting dangerously and I need to be ready to react to them.
And the police don't enforce this.
> building a distance buffer", that is the proxy the insurance companies want to use for risk assessment.
The cam car did not need to have a hard braking event (HBE) to start building distance.
Even if they did, the insurance companies are looking for a pattern of HBEs to assess risk. I agree that there is a theoretical high-risk driver that never has a HBE because they always try to maneuver instead of breaking. There are other heuristics for this (high lateral acceleration, high jerk). And the ultimate heuristic: failing to avoid accidents, thus having a claim history.
As an Indian, i was just expressing my frustrations in a jokey manner.
Yes, in a country where safe driving is not internalized you will inevitable have someone rear-ending you while doing this, but if the options are "accident where you're at fault" and "accident where you're not at fault", pick the latter.
Escalation usually doesn't improve things, including for the person displaying the universal finger (or throwing the lug nut).
You've got a choice: You can keep plodding along in your truck while you escalate and retaliate and get all grumpy and stuff, or just keep plodding along in your truck without any of that noise.
The errant, instigating driver won't really learn anything either way.
I, uh, okay but I hope you realize that this is far more extreme than what the other person was suggesting!
Exiting and immediately reentering a freeway is also less extreme.
Calling the cops if someone that is raging at you follows you when you do that is not extreme.
Nobody suggested "driving all over creation".
I think if you reflect a bit you'll find you are being the same kind of person as them, if you are getting angry that you have to slow down and give up space for someone else. I understand some people can be aggressive though, that can be frustrating regardless of the outcome.
We're not talking about where they're changing lanes to take the next exit. We're talking about where your lane happens to be moving faster, so they merge in front of you in an unsafe way to take advantage of that and just stay there. Why should you be expected to give them space, as you suggest? How is that fair, that they should get to their destination faster instead of you? Do you not see how that's going to rightfully make someone angry? When they should be waiting for a safe space to open up, rather than forcing you to slow down to create one?
that's hardly safe when it's already tight with a safety buffer as it is.
provided they use a signal as required by law and taught in the drivers handbook, they'd likely be let into the new lane without any judgement.
>> It's frustrating because . . .
> Slow down a bit to create another buffer
> I think if you reflect a bit you'll find
A third perspective may be "game theory." I think the Prisoner's Dilemma [0] could explain some aspects of the physical/mental problem. In the set below, Driver A's strategy isn't dependent on a singular predictable Driver B but all drivers that may perform the role of Driver B during the course of a commute.
Agent Cooperate Defect
Driver A leaves space doesn't
Driver B^n merge stay
I conjecture that this is a collective action problem and that above a certain traffic saturation point there must be a social taboo against changing lanes.
This is not to claim that individual perspective shifting is not important. I am reminded of Foster Wallace's Kenyon address "This is Water," [1] quoted below. However, the task of changing individual perspectives is vastly higher energy than the creation of a social taboo, which is why purity codes and other social inhibitors are so prevalent.
If I choose to think this way in a store and on the freeway, fine. Lots of us
do. Except thinking this way tends to be so easy and automatic that it
doesn’t have to be a choice. It is my natural default setting. [...]
The thing is that, of course, there are totally different ways to think about
these kinds of situations. [...] [Maybe] the Hummer that just cut me off is
maybe being driven by a father whose little child is hurt or sick in the seat
next to him, and he’s trying to get this kid to the hospital, and he’s in a
bigger, more legitimate hurry than I am: it is actually I who am in HIS way.
Now you've just created a shockwave traffic jam.
> someone is taking your safety buffer as their opportunity to travel faster
Nobody is 'taking' something; we're all just sharing the road, and at little cost. People change lanes for many reasons, and sometimes to pass someone else and travel faster. That's what the left lane (if we're talking about the US) is for.
> results in you having to travel slower and slower to maintain the gap that is constantly consumed,
I understand the theory but that hasn't happened in my experience.
And even if five or ten cars got in front of you, how much distance is that? A random Internet site says the average midsize car is 16 feet; add 220 ft safe driving distance at 75 mph (says another random website), so let's say 240 ft per car x 10 cars is 2400 ft. In that extreme circumstance, it will cost you ~30 seconds.
It's self-fulfilling: If you act aggressively toward other drivers, they will respond in kind. If you treat them respectfully and politely, they act the same way toward you. People behave well and kindly, naturally. We are social creatures.
It's the people who aggressively slide right over just a few feet in front of me (cutting off nearly all of my safety buffer) without so much as a signal that really drive me nuts.
So for the love of gods, if you're merging, even if you signal, match speeds for merging. If you're too slow to match speed, then suck it up buttercup, and hang out in the right lane until there's an opening.
I've had times where the right lane ends up being the fastest. On I-5 near Woodburn, OR, it's 3 lanes. So many drivers, including truckers, will often stay out of the right lane entirely to avoid being caught up in traffic coming on/off. Meanwhile, the left lane is going 5 mph under the limit because there's a left-lane camper somewhere miles ahead. So I can fly past everybody in the right lane because there's actually barely any traffic coming on/off and everybody is avoiding the right lane for no reason at all.
What I really hate, however, is that plenty of people will cruise in the center lane but still not leave a decent gap between them and the car in front. They effectively turn a three lane freeway into two one-lane freeways by hobbling the ability of anyone else to switch lanes. The freeway moves way smoother when there is a modest, predictable speed differential between each lane so that people can find their way into the next lane over without having to force the issue.
At 30 mph how much later will you be? 37 seconds.
I’ll take that trade.
At over 100 km/h that would be ideally 5m for a car and 70m for a safe distance between each one so 7,5km, which is 4.5 minutes at 100 km/h or 9 minutes at 30 mph.
You're ascribing motive where you have no data to do so.
> travel slower and slower
Roads near capacity slow down. This capacity surge is typically highly predictable.
> tragedy of the commons style, by opportunists.
People can only drive one car. They cannot drive two at the same time to get there twice as fast. I don't think this logic applies.
This exemplifies the problem with America. People will cut off their own welfare to make sure their neighbor doesn't get any either.
All of the people tailgating are contributing to the congestion.
The train of tought goes something like this. You want to get to your destination quickly as just like everyone else and are doing everything correctly, but the assholes exploit that safety distance as a gap available for them to switch into and repeatedly forcing you to break to maintain a safe distance. Oh and the even less rational people think everyone overtaking them has stolen their rat race position.
Leaving a keeping a safe distance feels unsafe since other drivers will squeeze into it. Subjectively it feels safer to close the distance, but the numbers don't lie. Tailgating kills.
It's especially not people trying to get off the highway because then they leave and you can catch back up to where you originally were.
Putting my armchair psychoanalyst hat on: I think American society embeds a need to be the "winner", and are you winning if end up behind another driver who's contending for "your" spot?
If you've driven elsewhere for a while, you start noticing subtle driver differences, such as drivers who want to merge into your (slower) lane never braking to merge behind you and always accelerating to do so, even when you're at the tail end of a vehicle chain in your lane.
Comparing to the experience of being a passenger on a bike in Saigon, the level of cooperation there is way higher, possibly due to a sort of necessity. I had this feeling while observing traffic there, that, while the latency and throughput of the roads during high traffic times are still kinda awful, at least for bikes there's a slow continuous progress that simply wouldn't exist without cooperation.
Funnily enough, my experience driving in Los Angeles was distinctly not terrible. Traffic was usually good enough to drive in, though there was very little regard for the speed limit on the freeways! I suspect I may have just been lucky to miss the worst of the traffic.
This ensures that
a) I do not cut anyone off accidentally, and minimize the amount of stress in my immediate part of the universe
b) I will (most likely) have plenty of room behind me after I change lanes, reducing chances of anyone else running up on me
c) If there's noticeable traffic, the time I spend signaling and waiting for the person to move slightly ahead of me gives plenty of warning to the people _behind_ them that I'm about to enter the lane.
Ultimately, yes, of course in principle you're right, when I change lanes, I enter the lane in front of someone.... but I _can_ control whether I enter as far as possible ahead of them.
And in inclement conditions, it can make the difference between losing control of your vehicle or not. When you brake, you decrease your steering ability in most cars. Fine when its calm and sunny in CA, not so much when it's icing over near Ashland OR on the pass.
My point is, it feels safer and easier to aim to enter a new lane with the aim of "following" someone, rather than trying to rush in "ahead" of someone. But maybe it's just me.
It doesn't even have to be real. There's huge room for miscommunication. Unpredictable movements and perceived aggression, or unwillingness to be considerate to other drivers on the road, there's a whole wealth of information being processed, regardless of how little is actually real.
Now add the total lack of accountability for the driver's emotional state (don't you love yelling at other drivers, completely free of judgement?), and you can see how things spiral into road rage so relatively easily, even if everyone involved is normally a pretty chill, rational person.
If you're tailgating or brake-checking, or being inattentive and sloppy, you're basically threatening people's lives with a few tons of high speed metal, even if you don't intend that at all.
Ideally, the rules of the road are meant to reinforce a mutual understanding of the game being played. Behavior occurring when expected, proper signaling, observing limits, and making the effort to communicate where possible is a signal that you and the other driver are both operating by the same set of rules, giving you both confidence that neither of you are going to be a danger.
I've seen little "cute" exceptions where locals develop a subculture of dangerous assumptions and then get aggravated when someone from out of town doesn't immediately get it. There are other areas where aggression and what amounts to flagrant disrespect are the norm, so you've always gotta be adaptive, but ideally you get people conspicuously following the same set of rules as a sort of game theoretic optimal strategy for driving.
It's simply not possible to merge during heavy traffic without eating into someone's safe following distance.
I don't drive as often as I used to, but on I-76 coming into or out of Philadelphia, traffic gets snarled and becomes stop-and-go. Every now and then, someone next to me appears to have the same understanding of fluid dynamics as I do, and we build up enough of a buffer that we are able to eliminate the stop-and-go, even if it means rolling at 5mph with a big gap between us and the cars in front of us.
There's no good way to communicate what we're doing, even to each other. But I like to think that when this happens, it has a positive effect that ripples out for miles.
Yup. The brake pedal is an evil device that converts cash into brake dust and waste heat. Before I got an EV, I always drove in such a way to use the pedal as little as possible. As a result, in my previous car that was stickered at 24 mpg city/30 mpg highway, I averaged 32 mpg. I don't even drive slow, I just drive smoothly. If your average speed is going to be 5 mph, then you'll get much better economy driving a constant 5 mph than your speed being a sine wave between 0 and 10 mph.
Good driving instructors make you aware of that early on, at least mine did.
I'm not saying that I'm a good driver, because I make mistakes like any other driver out-there, it's just that I oftentimes go with the "maximize the flow" thing instead of just following my individual "well-being" as a driver as a result of what my driver instructor told me some years ago.
Adam Something has a video responding to it that's worth watching too: https://www.youtube.com/watch?v=oafm733nI6U
The entire reason this happens is because 98% of people are morons who drive up the next guy's ass. If everyone kept a proper distance it wouldn't happen at all.
In Austin if you want to merge, decide if you can, blink and then merge.
Don't expect people to stomp on their brakes and stop to let you in, especially if your already traveling slower than the lane you are trying to get into and decide to further slow yourself.
And if you can't merge, deal with it, exit, or miss your exit and go around. Next time you will be more prepared or you will learn how to properly merge.
When flows merge, there's turbulence. There's less turbulence if the flows are more closely matched, including speed.
And are we in different societies now?
The section of I-5 between Portland and Salem is absolutely psychotic, and I have never been able to reason out exactly why. It consistently has a left lane jammed with angry people going at or below the speed limit, a fairly normal center lane filled with cruisers, and a mostly empty right lane with the occasional big rig and regular very-high-speed cars expressing their frustration with the left lane by going 25+ mph over the limit in the right lane.
I know that's what you basically just said. Just venting. The driver behavior in that section of freeway confounds me, and I do not know what the underlying cause is. It is otherwise an unremarkable bit of interstate like any other.
Banning passing on the right only works if keep-right-except-to-pass laws exist and are thoroughly enforced. Most states in the USA don't have keep-right laws, and those that do, it's never enforced, so many people don't even know it's actually the law.
EDIT: US-26 westbound immediately outside downtown Portland is notorious for left lane campers. The limit is 50 mph, but without fail, there's some moron going 40 mph in the left lane. You wanna go slow? Fine, but do it in the right lane where you belong.
OTOH, most states have a stay right except to pass, slower traffic keep right laws.
Which means, that unless the person to your right is weaving through traffic, driving on the shoulder, or a few other bits of unsafe behavior, if someone passes you on the right your likely the one violating the law by not moving right when your not actively overtaking/passing someone.
I much prefer cars with short gearing for better engine braking. I continue to choose to drive a manual party for better engine braking.
There are plenty of ramps on I5 and 205 that I merge to the left for because I know they will spill into the right and (when it exists) middle lanes. Because of how traffic also reacts to brake lights (some people brake too hard even when they have sufficient distance to let off the gas and coast to a slower speed) it seems like it ends up making my experience through those stretches a bit better.
Ultimately, any individual behaviour is largely irrelevant, it's what the whole mass of cars moving along does that affects things the most. Often you don't want to be the (significantly) odd one out regardless of the situation.
Would I love to see CHP or OHP fine every left lane trucker in the 'no trucks in left lane' zones? Hell yes, but until that happens, I understand the trucker behaviour.
When asked, they'll say they feel safer in the left lane because they don't feel safe having to deal with people turning out and merging. So you get instead people driving fast in the lane meant for pulling out and merging.
Reasons vary, but a lot of the time it can be explained by left exits/splits ahead on the highway. Which some may call poor design.
Common misconception, actually.
There is not a single state in the USA where using the right lane to pass slower traffic in the left/center lanes is illegal. It is allowed everywhere.
So the laws do exist, they just are never enforced. Even when said left lane campers cruise by state patrol, I never see them stopped. Hell, I rarely see them stop people going 15+ over the limit either so not actually sure what they're doing.
If they'd just drive 70 on cruise control, they'd be faster, less traffic jams and less fuel use...
I really would like to see some mandatory use of cruise control on some stretches of highway, even if just as an experiment
There is no solution to traffic here sorry, this is more about managing your own frustration and expectations when faced with people at their worst, in the worst form of transport.
The total, confirmed, 100% effective solution is to never commute by highway during peak hours, but few get that option.
There is, people just don’t want to hear it, and it isn’t a quick fix…
Build more of our towns and cities such that driving everywhere isn’t necessary.
I do think some don't appreciate that it is not an anti-car stance to wish for less car dependant cities. You still get to have a car, and commuting by car should be easier if you need it, since there is less demand on the limited resource that is the road network.
Ehto is correct and this is the way. I'll go further and say that if someone is tailgating you and it's pissing you off, generously let them pass. Literally pull to the side of the road if you must.
It’s safer to drive a little closer, keep up with other traffic and defend what gap you can in front of you.
Agree with your conclusion here, though. The best response is to simply not drive in this kind of traffic.
If traffic is very busy, the trick is to just accept people will wedge in front of you and keep going slightly smaller each time to increase the buffer again. You might create 'turbulence', which might possibly decrease the safety a bit for all the impatient drivers doing the wedging. But it increases your own safety. And therefore also that of the people following you and your passengers.
I'm also not convinced on the 'turbulence' part. Keeping a buffer smoothes out any sudden speed variations of the people in front of you, which makes the traffic behind you flow better.
And it might maybe feel a lot slower to let a 100 cars go in front of you on your commute, but just driving 99km/h when the person in front of you does 100 is enough to increase your gap and it makes a whopping 1% of difference.
The only thing is: sometimes a road is just too busy and the space for a buffer just isn't there to begin with. At that point the speeds should go down to accommodate the smaller buffers, which is actually what happens here in the netherlands as long as there aren't too many people ignoring the speeds advisory boards above the highway.
That's very obviously not true. Slowing down always reduces energy in the system and always reduces global turbulence. It's one of the reasons that countries that lower speed limits see journey times reduce.
Everything I've read points toward larger margins of safety (longer distances, slower speeds) being safer.
See e.g. https://publications.lib.chalmers.se/records/fulltext/252480...
If you choose to go in the fastlane in traffic you should understand that it will have people who do not care about the following distance as much and are just trying to go as fast as possible.
I have found that often times in heavy traffic the rightmost lane can be just as fast or actually faster than a middle or left lane.
The most efficient throughput of the road system is not for people to “politely” queue up for 5 miles. People should be utilizing the rod and merging in an orderly manner. By adopting some arbitrary self imposed practice that is leading to 20 drivers cutting in front of you, are the one creating an unsafe situation.
Correct, but you _need_ the asphalt in front of you for both safe driving and also to avoid cascading hard braking events. I also don't own the asphalt under me or behind me too, so it's kinda a silly statement tbh.
This youtube talks about it: https://www.youtube.com/watch?v=iHzzSao6ypE
If you do that and get angry when people change lanes in front of you, you have consciously or subconsciously decided you own that 20 foot gap. That reaction impairs judgement and causes accidents.
Screwed person: WTF?
People doing the screwing: ‘oh thank god’
The really irritating part - society saying ‘oh, that’s not happening you should continue to be screwed’
Besides, there are only a few people who ever merge in front of me (and then those who don't merge block their lane so nobody else can get in).
30 seconds later, so what?
In my experience even cars that are not trying to go faster will happily merge in front of you unsafely all the time, just because they don't understand the concept of a safe distance.
It's not about choosing to go in the fast lane. It's about the fact that in heavy traffic, you have no idea which lane will be fastest, because they're all heavy and which one is fastest keeps switching.
> I have found that often times in heavy traffic the rightmost lane can be just as fast or actually faster than a middle or left lane.
That's exactly my point. Which is why you can be in the right lane, and tons of people from the slower lane will try to merge in front of you if you're keeping a safe distance from the car in front.
Your advice is staying in the right lane doesn't apply in these situations.
Their old lane speeds up because many cars departed it
Everyone merges back to their old lane
You're back where you started.
Again we are not talking about the fastest lane here we are talking about the safest as the OP was concerned about following distance.
> That's exactly my point. Which is why you can be in the right lane, and tons of people from the slower lane will try to merge in front of you
If everyone merged right it would not longer be faster but people do not do this. In the right lane you can slow down as much as you want and never cause an issue so you can always make a gap. In any other lane if you slow down more than traffic you cause issues because people will then try and pass you from the right which is dangerous.
You are placing the burden of your forward following gap on the cars around you but that is a terrible way to drive. You need to be in control of yourself when driving, do not trust that someone is going to follow traffic laws, do not trust that they will go whatever way there turn signal says, do not trust that they will look over there shoulder before merging.
If YOU want a following gap then the only possible safe way to do this is to merge all the way right and slow down whenever someone merges in front of you. There is no other way to do it in heavy traffic. And YES you will have to live with the fact that you will be driving slower than the traffic around you. That's the trade you make if you choose to have a large following gap.
We don't live in an ideal world, and having a bunch of cars merging in front of you definitely makes you less safe than having a static situation. I try to make sure I can see through/around the car in front of me, so that I have advance notice of what's happening down the road.
We in Colombia had a public service announcement where it showed someone driving really fast (while still respecting semaphores), and another one going with just enough speed. In the end, they both reach the last semaphore almost at the same time and then they part ways. Essentially it shows that driving crazy fast in the city doesn't necessarily gets you faster to your destination.
Now that I'm an adult, I tested it several times, and it matches 90% of my attempts, but that's in the city, with semaphores. No way I'd think letting everybody steal everybody else's buffer would provide for a reduction in journey time, even in highways. You're adding items to a queue, it'll take longer.
Now, it is probably safer, but we can only take so much even if we are not in a rush.
> Slowing down on a busy highway does not reduce turbulence at all,
The only thing that reduces global turbulence reliably on any roadway is reducing speed. All the simulations and real-world implementations show this. It's unambiguous and uncontroversial, except that it requires drivers to slow down, which is politically untenable in many jurisdictions.
I agree that slowing down "suddenly" causes turbulence. However, slowing down *gradually* allows you to build up a safety buffer which in turn allows you to avoid slowing down suddenly.
But I guess we should just all self gaslight to feel better about it?
Still, I tend to find that people underestimate the danger of short distances. Often it's just better to accept a 100 cars going in front of you than to shrug off following someone at 1.5 seconds. It can go well for years because crashes are rare, but when you are in a crash you will be royally screwed when you don't have the reaction distance needed.
Simply put: follow distance is not a unilateral decision.
I'm still convinced people decide way too soon that the 3 second distance is more dangerous. You might be right if people are constantly cutting in the moment you leave a gap, but if someone cuts in every 5 minutes you're still safer off with the gap.
This is correct, but I get the sense that people overestimate Y.
Let's say you're driving 60 mph and following the "three second rule" which gives you a ~264 foot safety buffer. A driver then cuts into this safety buffer. Let's assume they like to go fast and enter closer to the front of the buffer so they reduce your safety buffer down to two seconds. In response, you gradually rebuild the safety buffer back to three seconds, costing you an extra second. Soon after you rebuild the safety buffer another car cuts in front of you. Let's say this process repeats every mile of your journey, costing you an extra second every time. This results in you traveling slightly over ~59 mph, making Y = ~1 mph.
Compare that to the lifetime odds of dying in a car crash in the U.S. which is roughly 1 in 100. It's hard to eliminate that entirely, but I'm willing to spend an extra ~1s per car that cuts in front of me to reduce it for myself and my passengers.
True, though-
I like being a traffic hacker--come on in, plenty of room!
If you personally start with that slower speed to begin with (AKA much longer following distance), you don't have to worry about adjusting down
For example, the specific law in California: https://leginfo.legislature.ca.gov/faces/codes_displaySectio...
Obviously fast and slow are just colloquial terms.