Portland State crosswalk study looks at factors affecting pedestrian safety
A new NITC report examines factors that predict whether a driver will comply with Oregon laws aimed at keeping pedestrians safe.
Miguel Figliozzi of Portland State University, director of the Transportation, Technology & People (TTP) research lab, has done extensive work in Portland, Oregon modeling and analyzing the complex interactions between cars, transit, traffic signal technologies and human roadway users.
The research seeks to provide a better understanding of the tradeoffs between traffic mobility, transit performance and pedestrian access.
The first phase of Figliozzi’s research focused on how two advanced traffic control technologies work together. In this second phase, he zeroes in on pedestrian safety.
The report examines traffic and trajectory factors that explain whether a driver complies with Oregon law, which has strong pedestrian protections. In Oregon, drivers must stop for pedestrians as soon as they move onto the roadway in a crosswalk with the intent to proceed.
Oregon state law determines that there is a crosswalk at every intersection with or without a marked crosswalk. The state also requires that a driver, before crossing a crosswalk, stop and remain stopped for pedestrians until the pedestrians have cleared the lane in which the vehicle is traveling and the next lane – an area known as the safety buffer. If a pedestrian is in the safety buffer when a vehicle enters the crosswalk, the driver may be cited for a fine over $260.
For data collection, the research team chose the intersection of SW 4th Avenue and SW College Street in Portland, Oregon.
The intersection was chosen for two reasons: it had a high number of citations for failure to stop for pedestrians, and researchers had access to a university building rooftop to install video recording equipment.
The team placed several cameras at different heights to analyze driver and vehicle trajectories up to 200 meters (650 feet) upstream of a crosswalk.
The modeling results found that speed and headway changes (the distance between vehicles), as well as driving trajectory before reaching the crosswalk, are the most significant variables to predict whether a driver will be in compliance with crosswalk law.
They found that vehicles accelerating toward the crosswalk – particularly those that had just come off the nearby Interstate 405 – were less likely to stop the recommended 30 feet before the crosswalk.
Drivers of SUVs and pickups were found to comply less than smaller passenger vehicles; a concerning finding considering the greater potential damage from heavier vehicles.
Compliance rates were also affected by whether a driver had already stopped at an upstream traffic light or had other reasons to slow down prior to reaching the crosswalk.
Results indicated that drivers are more likely to comply with the pedestrian law if the pedestrian stopped while crossing or had to speed up in response to approaching vehicles.
The results suggest that treatments or driver notifications that discourage accelerating towards the crosswalk would be most useful to increase compliance.
It is also important to monitor vehicles' speed profiles near crosswalks in arterials with signal progression or in areas with a high number of pedestrians. Enforcement and education campaigns can be useful to lower noncompliance rates, but they should be complemented by appropriate engineering designs.