The Fantasy Automobile Driver

Strong Towns has a solid post on the The Cult of the Fantasy Pedestrian. It describes how engineers appear to harbor an unrealistically immaculate vision of how real life pedestrians behave. The example used is a crosswalk in front of a library in Springfield, Massachusetts.

In real life, people don’t always follow the rules. Should society provide affordances for this behavior?

Switching the perspective to automobile drivers, there are many drivers who die from taking curves way too fast. If there is a road curve that is consistently causing collisions or driver deaths then it seems to me an obvious example of a design issue. Widening the curve is definitely one remedy, but only one kind of remedy. You could look at the roadway leading up to the curve, and examine whether its structure (e.g. wide straight lanes) encourages a speed which is inappropriate for the upcoming curve. You could examine the sightlines of the curve and see if some barriers obstruct the fact that there is a curve. None of those solutions are necessarily the correct one, and you naturally have to weigh the options against other considerations.

Roadway design is full of meeting people where they are, even if they're breaking the rules. Speed bumps are to mandate slowing down. Knowing that people will be distracted, either by lack of sleep or smartphones, rumble strips are a fantastic idea. Knowing that people will take their chances and try to brave a yellow light at an intersection, a period of time where all directions are red is prudent (this is called "all-red clearance time"). You can mandate speed limits all you want, but people generally drive to a "natural" point that is necessitated by the design. The best indicator of a low speed isn't the mandated speed limit, but rather narrow lanes and multiple gentle curves. There is also a strong argument for getting rid of signing altogether to put drivers more on notice. Similarly, a shockingly high number of traffic collisions are caused by unrestricted left turns (so much so that UPS almost never directs its drivers to use them). You could just tut-tut the drivers that chance it and scold them for "not following the rules" OR just implement something like protected left turns even though it potentially slows traffic. More radically, you could just get rid of left turns altogether and implement something like roundabouts which get rid of traffic conflict lines and encourage your attention towards only one direction.

There are many many more examples, and so many are baked right into completely conventional road design.