New York City initiated its Summer Streets program in August 2008, opening 11 kilometers of Park Avenue in Manhattan to pedestrians, cyclists, rollerbladers and joggers and creating vehicle-free streets for three consecutive Saturdays. Summer Streets provides a shared space for people of all ages and abilities to share the streets respectfully.

I coauthored this study, which was recently published by the TRB. This work uses automated extraction techniques to analyze road user behavior (pedestrians, cyclists, rollerbladers and runners) from video data. Road users’ speeds and pedestrian gait parameters (step frequency and step length) were automatically extracted and analyzed with the objectives to diagnose road users safety issues during the Summer Street’s normal operation and transition period, as well as test the extraction of data for non-motorized users to understand behavior. To evaluate safety, traffic conflicts were observed. Traffic conflicts are defined as “an observable situation in which two or more road users approach each other in space and time to such an extent that there is a risk of collision if their movements remain unchanged” and are a great alternative to traffic collisions when studying safety because they are more commonly observed and not serious to injury, damages or fatalities. In the study, the Time-To-Collision (TTC) indicator was used, defined as “the time that remains until a collision between two road users would have occurred if the collision course and speed difference are maintained.”

Findings show that the lowest rate of “conflicts” between pedestrians and cyclists is found to be during the Summer Streets shared space operations, mostly likely because cyclists are travelling slower since they do not need to compete with vehicle traffic. Shared spaces, as seen here, are opportunities to slow down all traffic, including non-motorized traffic, and it is recommended that North American cities implement more shared spaces to create safer streets for vulnerable road users.

Summer Streets