Here’s my idea: A special highway lane that you can only be in if your cruise control is activated. Sensors in the road would set the speed and spacing for everyone, and it could exceed the normal speed limit if conditions allow. An automated convoy of sorts.

I argue that a more effective measure would be to use the onboard data services in modern cars to calculate the $ cost of speeding! Sure, you CAN drive 85 MPH, but if you drove 70 you are saving $/hour driving.

False correlation.

Yes, speed is such a significant factor in the severity of accidents that it can be isolated as a sole point of focus. That does not hold true for the frequency of occurrence.

Increased speed does increase the probability of an accident but not so significantly that it can be isolated apart from other contributing factors. That is significant because as other factors contribute more to the probability of accident controlling for those factors reduces both the number of accidents and thus the number of accident fatalities.

Ignoring this logic results in bias and thus an incomplete or faulty solution. People always want to isolate for controlling for speed because of over simplification, or rather a hasty conclusion.