The subject of crosswalk visibility came up in a conversation I recently had with a Bucks County Courier Times reporter. We were talking about the recent pedestrian death while using the crosswalk at N Sycamore St and Silo Drive (read “Sycamore Street Is Popular, But Is It Safe?”). It was suggested that the brick crosswalk (see photo below) is difficult for drivers to see at night.
I’m no expert on the visibility of crosswalks, but the people at the U.S. Department of Transportation and the Texas Transportation Institute are. In 2010, these experts investigated the relative daytime and nighttime visibility of three crosswalk marking patterns: transverse lines (e.g., like the crosswalks on N Sycamore St), continental, and bar pairs (see figure below).
These markings are used in conjunction with signs and other measures to alert road users to a designated pedestrian crossing point. Although the Manual on Uniform Traffic Control Devices (MUTCD) contains basic information about crosswalk markings, many municipalities develop practices that are not discussed in the MUTCD.
The following is a synopsis of a “TechBrief” of the 2010 Crosswalk Marking Field Visibility Study.
In this study, participants drove an instrumented vehicle on a route through the Texas A&M University campus in College Station, TX. The route provided an open road environment that included portions in a typical college setting (e.g., sidewalks, buildings, basketball arena) and roads through the agricultural area of the campus, which were more rural in feel. Roadway lighting was present at each of the crosswalk locations. The study vehicle was equipped with instrumentation that allowed the researchers to measure and record various driving performance data. However, the vehicle operated and drove like a normal vehicle.
The detection distances to continental and bar pairs are statistically different from transverse markings. A general observation is that the continental marking was detected at about twice the distance upstream as the transverse marking during daytime conditions (see figure below). This increase in distance reflects 8 seconds of increased awareness of the crossing for a 30-mph operating speed.
Based on the findings from this research, the researchers recommended that municipalities consider making bar pairs or continental the “default” for all crosswalks across uncontrolled approaches (i.e., not controlled by signals or stop signs), with exceptions allowing transverse lines where engineering judgment determines that such markings would be adequate, such as a location with low-speed residential streets.
Posted on 06 Jan 2022, 13:08 - Category: Public Safety