A Tale of Two City Streets: Evaluating the Safety, Congestion, and Cut-Through Effects of Road Diets

Every year, more than 200 people are killed in Los Angeles while walking, bicycling, or driving. In 2015, Mayor Eric Garcetti launched a citywide Vision Zero initiative, which set a goal to eliminate traffic fatalities by 2025. One key tool the city can use to improve traffic safety on dangerous roads is the road diet, a reconfiguration of lanes that removes vehicle travel lanes. Road diets often face opposition, though. This opposition typically stems from fear of increased traffic congestion and neighborhood cut-through traffic as well as doubt that road diets actually improve traffic safety. My project analyzes crash data, traffic count data, and bluetooth travel data on two similar streets in Northeast Los Angeles to gauge whether road diets have these effects. One of the streets underwent a road diet in 2016 while the other didn’t, making them an effective test case. My analysis of shows no evidence that the road diet caused unacceptable traffic conditions or additional neighborhood cut-through traffic. I also find some evidence that the road diet improved traffic safety outcomes. My review of the literature bolsters my findings that road diets are an effective safety countermeasure and that in most scenarios they do not cause unacceptable increases in traffic congestion. The literature on neighborhood cut-through traffic is much less developed. Based on these findings, I recommend that Los Angeles identify additional opportunities to both research and implement road diets