Smooth Sailing for Cyclists
https://www.nytimes.com/2019/10/23/nyregion/nyc-bike-commute-green-lights.html
This article discusses traveling networks and how redistribution can favor one group over another. Due to an increase in fatal cyclist accidents, New York City has calibrated the traffic signals to give bikes priority for green lights. By timing the lights for a 10-15 mph pace, as is typical for cyclists, they are able to have a more continuous route, without stopping for red lights. However, for cars, those who go faster than 15 mph are more likely to hit red lights, increasing their travel time as they wait for the light to cycle. The city expects to see an increase in bicycle commuters given the favorable travel times and notable accommodations for their safety. In addition to the safer and less stressful environment for cyclists, the new system also ensures a more even and predictable travel speed for everyone sharing the road, hopefully leading to fewer accidents.
This example shows how Braess’s paradox cannot always predict the outcome of adding new routes in a traveling network, and how adding or improving route options can be beneficial. In this case, the two routes are compared under more conditions than travel time, including such factors as safety concerns, weather conditions, and physical exertion and accessibility. NYC focused on improving both the safety and efficiency of their biking routes by timing the traffic lights to typical bike speeds. For cyclists, this system has been shown to improve their routes and travel times; a portion of downtown Chicago, where traffic signals were retimed in 2015, has shown an increase in average morning bike speed of 64 percent from 6 mph to 10 mph. Given this new, more optimal, travel route, it is expected that more commuters will leave the more crowded routes, such as the subway and bus systems, in favor of biking. Unfortunately for drivers, one location using this system showed a slow down from an average 17 mph to 12 mph. Given the “green wave” in transportation, it is likely that the improved biking routes could outweigh the negative effects to car commuters, and result in a net positive effect on commuting. Though largely unpredictable and variable, more commuters will likely switch to biking, until the other systems are sufficiently alleviated, and travel times in utilizing different systems are in equilibrium.