A year or so ago I found an incredibly well made website that showed isochronic areas from a given address. Now - there are several of these types of websites, most are terrible, but this one that I can't find again had the following features:

* it worked in the Boston area (among other places)

* it allowed you to pick time of day

* it allowed you to pick mode of transportation

* it allowed you to pick more than one location and showed the intersection

* I believe the isochronic blob was pink by default

* it was completely free (at least at the time)

Does anyone know which website I'm talking about? I haven't been able to find it with google or searching my history, which makes me think it doesn't actually use the "isochrone" word on the website. And of course my memory could be off. The best one I've found is https://commutetimemap.com/map?places=38.882926%253B-77.016391%253B0%253B1800%253B%2523ea41f4 but it doesn't seem to let you change time of day.