[benrbray]

Can you or any other traffic engineers here tell me why we find it acceptable that cars are allowed to make unprotected left turns while pedestrians have a walk signal? Right turn on red is bad enough, but unprotected lefts give drivers a direct incentive to torpedo into crossing cyclists / pedestrians, as slowing down would mean a collision with oncoming traffic! Too many intersections in downtown Atlanta, for instance, have no left turn arrow, and I felt constantly in danger.

[SECProto]

Most North American road infrastructure has been rebuilt over the last century to be automobile-centric. "We" deem that conflict to be acceptable because the alternative is more complicated phasing - most of which results in delays to car traffic (and pedestrians!), and so most places won't accept it. For details, here's [1] a document that outlines the tradeoffs in various different signal phasing designs.

TL;DR is that "we" won't prioritize any road user except the automobile.

[1] https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter4....

[takk309]

I agree completely with this comment. Most places signal timing is done with the main scoring metric of reducing vehicle delay. Pedestrians are just an after thought that can be squeezed into a vehicle specific timing plan. As an example, how often do you see a pedestrian scramble, walk signals in all directions, outside of somewhere like Time Square?

[benrbray]

Some of the problematic intersections in Atlanta have slowly been replaced with scrambles, and it's amazing as a pedestrian. I hope to see more and more of those!