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New York, NY
Prepared by Michael King.
Incremental improvements to crosswalk design and increase of aggressive driving throughout New York City created a situation where the crosswalk marking used to delineate safe walk-to-school routes (the MUTCD “ladder”) was the same as the marking for dangerous intersections, sending a conflicting message to school children and others using the city’s sidewalks. Moreover, neither crosswalk was providing adequate safety for the large volumes of pedestrians found on many New York City streets.
Overlapping delineating crosswalks sent conflicting messages to New York City pedestrians.
Delineating crosswalks with thermoplastic striping is intended to communicate a message to both drivers and pedestrians. For years there were only two types of markings used by the New York City Department of Transportation—simple parallel lines and the ladder. Parallel lines were used at signalized intersections and other locations where drivers are expected to stop for pedestrians. The ladder was used to highlight a particular location such as a preferred route to school or a dangerous crossing point. Initially, crosswalks warranting ladder treatments (school or dangerous) occurred in separate parts of the city so there was little overlap.
The use of the ladder crosswalk to mark dangerous intersections increased, with the spread of aggressive driving behaviors, changed attitudes about crosswalks, and the Department’s increased response to the concerns of the walking public. The different crosswalks created conflicting messages and made it impossible for the public to determine whether one should cross at a ladder crosswalk or avoid it altogether.
Standard Parallel Line Crosswalk
Ladder Crosswalk (school routes)
Zebra Crosswalk (dangerous location)
Opposing pedestrian platoons meet in the middle of a street. Volumes such as this represent 7000 pedestrians per hour.
Stop lines solve many of the city’s various crosswalk problems.
In 1995, the Pedestrian Projects unit of the Department of Transportation worked with the Roadway Engineering Division to introduce a third crosswalk marking called the “zebra,” solely for dangerous locations. This involved altering the width, use, and warrants for stop lines. In addition, it was one of the first instances where an ISTEA-funded unit created specifically to address pedestrian issues affected a change in citywide policy.
The “zebra” crosswalk is an adaptation of the ladder, which has two 305 mm (12 in) lines running the length of the crosswalk that close each end of the 305 mm (12 in) bars. In contrast, the zebra crosswalk has open-ended bars and uses a 610 mm (24 in) stop-line in advance of the crosswalk. This stop line is set back at least 1.5 m (5 ft) from the crosswalk. Ladder markings are now reserved solely for the school route network.
Previously, a dangerous location was defined when two or more pedestrians had been hit by vehicles for three years in a row in a specific crosswalk. To account for data irregularities and underreporting, the definition was changed to an average of two injuries per year within a five year period for an entire intersection. This also made it possible to install zebra crosswalks for an entire intersection instead of singling out a specific crosswalk. In new or reconstructed locations, intersections that were considered potentially dangerous could receive zebra crosswalks. Each of these policy changes allowed the agency to act proactively.
The issue of competing pedestrian platoons within a given crosswalk width was also addressed. Crosswalks in New York City are defined by law as the extension of the sidewalk across the road. Generally, the width of this extension is from the building or fence line to the parallel curb, though there are some instances when this width is not sufficient to handle all of the pedestrians using a crosswalk, such as when two opposing platoons of pedestrians meet in the middle of the street.
When a signal turns green, pedestrians cross en masse and meet their counterparts in the middle of the street. With larger platoons of 7,000 per hour, the sheer quantity of people exceeds a standard crosswalk’s capacity and people are forced to walk into traffic. This condition is exacerbated when vehicles block the crosswalk, a frequent occurrence.
Roughly two out of every three people hit by vehicles at signalized intersections in New York City are crossing with the light. If a pedestrian is crossing with the light, he or she may be struck when a vehicle is turning (most common), when a driver runs a red light (most deadly), or when he or she is walking in traffic because the crosswalk is too narrow.
Stop lines address each of these situations. They effectively widen the crosswalk without altering the legal definition of a crosswalk. Further, by removing the stop line from the crosswalk, it is free to be positioned independent of the crosswalk. It can be placed relative to the travel lane, aligned with a stop sign, street furniture or corner radius, or set further back to allow a larger truck turning radius. Essentially the design is now more adaptive to the situation, and stop lines are being used more often in the city at all types of crosswalks.
To evaluate the impact of crosswalk striping on pedestrian safety, a very limited test was conducted at nine intersections in lower Manhattan. Each of these intersections qualified as a high crash location where the vehicle-pedestrian crash rate averaged 4.2 per year, yet none were marked with either ladder or zebra type crosswalks. The speed limit on the streets was 48 km/h (30 mi/h) and ADT and functional classification varied.
Four of the intersections received ladder crosswalks, while five received zebra crosswalks with stop lines. A year later crash data were compared.
Vehicle-pedestrian crashes decreased from 16 in the year before the ladder crosswalks were installed to 8 in the year after. Crashes at intersections that received zebra crosswalks decreased from 20 to 13 over the same study period. Before the ladder crosswalks were added, pedestrian incidents represented 11.6 percent of all crashes. This proportion shrunk to 7.2 percent after the crosswalks were added. At the zebra crosswalk locations, pedestrian crashes made up 7.5 percent of all crashes before, but only 5.3 percent after the markings were added.
The value of both ladder and high visibility markings in terms of absolute crash reduction is positive; the number of vehicle-pedestrian incidents at the nine test intersections fell from 36 to 21, a decrease of 42 percent.
To evaluate the effectiveness of markings in keeping vehicles out of the crosswalk area, a limited survey was conducted at three intersections in lower Manhattan. Except for the marking type, all of the sites were similar in terms of direction, volume, lanes, and turning movements. The stopping locations of 72 total vehicles were noted.
The ladder crosswalk was the most effective marking for keeping vehicles out of the crosswalk area. While only 20 percent of vehicles at the unmarked crosswalk and 23 percent at the standard double line crosswalk stopped behind the crosswalk area, 59 percent of vehicles at the ladder crosswalk stopped at the appropriate location. Additionally, drivers did not seriously encroach upon the ladder crosswalk (7 percent) as much as the others (31 percent at the double line crosswalk and 60 percent at the unmarked crosswalk). A stop line would likely improve driver behavior further. The marked crosswalks also provided greater room for pedestrian platoons where it was needed the most, in crosswalks.
Typical thermoplatic costs (not including planning, design and installation):
The project was funded using federal Congestion Mitigation and Air Quality (CMAQ) funds programmed for Pedestrian Network Development.
Michael King, Architect
Traffic Calmer
126 Second Street
Brooklyn, NY 11231
Phone: (718) 625-4121
E-mail: miking@trafficcalmer.com
Ms. Randy Wade, Director
New York City Department of Transportation Pedestrian Projects
40 Worth Street
New York, NY 10013
Phone: (212) 442-7686
E-mail: rwade@dot.nyc.gov
NYC DOT Pedestrian Projects Web site: www.nyc.gov/html/dot/html/get_around/ped/pedest.html