The Impact of Segregated Cycling Lanes on Road Users
This paper investigates the impact of constructing segregated cycling lanes on cycling and motorized traffic. I use an event study analysis on the progressive roll-out of the Cycle Superhighways (CSH) programme in central London from 2014 to 2019. Analyzing the impact of lane segregation on traffic flows is challenging as cycling lanes location is an endogenous choice from the policy makers and stakeholders. Lanes have been built in strategic locations due to demand from users, wide enough roads to accomodate the additional segregated lanes, safety and potential for growth. However, even after taking into account the endogeneity of the locations, I still find that the segregated lanes programme increased cycling traffic flow by about 25% after opening and then by an additional 20% per year. It acounts for about half of the increase in cycling traffic along those roads. There is little evidence that this effect is driven by the displacement of cyclists from nearby roads, which indicates that the new lanes increase the number of cyclists or their frequency. One of the mechanisms investigated is an increase of cycling flow via safer trips and safety in numbers. I find indeed a substantial decrease in accidents involving cyclists after the lanes' construction. Similarly to other studies on the cycle lanes, I do not find any impact on car traffic