Let me explain, with the help of excerpts from three articles I recently read. First, from Citified, which reported on a recent study that showed that bike-share riders had fewer accidents than regular riders:
Janette Sadik-Khan recently wrote in New York Magazine about the mass introduction of bike lanes and related bicycle-serving infrastructure in New York City:
Finally, from the profile in Pennsylvania Gazette of Sam Schwartz, aka Gridlock Sam:
A second factor pushed the calculus even further toward building a high-capacity modern bridge: standard 12-foot-wide lanes would be safer than the Williamsburg Bridge’s 9-foot-wide ones. That was an all but universally accepted truth among traffic engineers. Except, when Schwartz mapped three years’ worth of accidents on the bridge, the data showed something counterintuitive: the bridge’s safest sections were where the lanes shrank to their narrowest points, near the support towers. Perhaps because they caused drivers to behave more cautiously, “grossly substandard lanes seemed to be the safest of all.”
Transportation infrastructure is designed by engineers using computer models but is consumed by finite and fallible humans. Where things feel more dangerous, humans take extra precaution, and their safer behavior more than compensates for the extra danger. This is the theory behind "naked streets": less lines and less signage means I have to slow down and figure things out, more than compensating for the reduction in physical helps.
It's an interesting premise...which will get flipped on its head once humans stop driving and start riding self-driving vehicles. However many years or decades out that is, let's be careful out there. Really.