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Case Study

Adam Clayton Powell Jr. Boulevard

Associated Publication: Urban Street Design Guide

New York City’s Adam Clayton Powell Jr. Boulevard, a historic street in Harlem that suffered from rampant speeding and frequent vehicle crashes, spans 2.2 miles between 110th and 153rd Streets. Prior to its redesign, this downtown thoroughfare posed a significant danger to public safety, with more serious injuries and fatalities than 88 percent of Manhattan streets. A two-part redesign in 2012 and 2013 has substantially reduced speeding, crashes, and injuries by reconfiguring the roadway to prioritize safety.


Before its redesign Adam Clayton Powell Jr. Boulevard had a 100 foot right-of-way (from curb to curb) consisting of a 10’ median island, three 12’ travel lanes, and one 9’ parking lane in each direction. Traffic counts were 25,247 vehicles per day. High volumes of pedestrians were forced to make crossings as long as 150 feet, with limited pedestrian refuge. Double parked vehicles often blocked the rightmost travel lane, while cars queuing for a left-turn frequently blocked the leftmost through lane, effectively leaving only the center lane for car travel and resulting in dangerous swerving and merging.

A May 2010 New York City Department of Transportation (NYC DOT) radar study of Adam Clayton Powell Jr. Blvd between W 133rd and W 134th streets revealed that 62% of drivers exceeded the posted speed limit of 30 mph, with a maximum recorded speed of 52 mph. The segment between W 110th & W 134th Streets had 464 total injuries from 2006-2010, 76% of which were motor vehicle occupants. Of all motor vehicle crashes during that time, 31% were rear-end collisions, often involving cars queuing to turn left. Furthermore, between 2006-2012 there were 12 pedestrian fatalities on Adam Clayton Powell Jr. Blvd.

The downtown thoroughfare exhibited the following problems:

  • long crossing distance for pedestrians
  • inadequate center refuge
  • high motor vehicle speeds
  • aggressive driving
  • difficult left turns for drivers
  • need for frequent lane changes


In 2009, NYC DOT staff considered adding a bike lane on Adam Clayton Powell Jr. Blvd, as the street represented an important link in the city’s bike lane network, with connections to Central Park. However, the project did not resonate with community members, who expressed no local interest in enhancing the bike network. NYC DOT tabled the project, but after a series of crashes resulting in pedestrian fatalities, officials took a fresh look at the boulevard. Staff found a notable pattern of late-night high-speed driving, with drivers frequently striking pedestrians in the lane adjacent to the median as the pedestrians attempted to cross. The initial proposal for bike lanes would not have changed the configuration — it only would have added a bike lane next to the three existing car travel lanes, and would have done little to improve pedestrian safety. Therefore, NYC DOT began conducting community outreach in preparation for a street redesign.


In 2011 and 2012, NYC DOT held a series of workshops focused on public safety. Staff conducted outreach to representatives from churches, senior organizations, and schools in order to collect broad public input. The community recognized the problem of reckless driving and speeding, but expressed skepticism about reconfiguring a historic street. Adam Clayton Powell Jr. Blvd is a community focal point with frequent parades and events, and the public voiced concerns that a dramatic reconfiguration would be detrimental to the historic quality of the street. In response to these concerns, NYC DOT worked to ensure that the redesign would still accommodate community events. The community also identified left turns as a major source of conflict, so NYC DOT’s redesign included a left-turn lane. The existing medians had extensive landscaping, maintained by a local group that voiced concerns about their capacity to maintain additional plants, so the redesign did not add any new landscaping. Following these workshops, NYC DOT produced concept drawings, which the public received with cautious optimism.


In order to assuage public concerns about the redesign, and in order to distribute the implementation over two construction seasons, NYC DOT split the corridor into two phases. Phase 1 Safety Improvements, implemented in 2012, covered Adam Clayton Powell Jr. Blvd from 134th to 153rd Streets. NYC DOT aimed to organize car traffic, eliminate expendable movements, shorten pedestrian crossing distances, and improve overall safety. The redesign restriped the street, creating a 10’ left turn bay, two 11’ moving lanes and one 13’ parking/loading lane in each direction. The wide parking lane accommodates the common practice of double parking, which is especially common on Sundays, but provides enough space for cars to stop without blocking a travel lane. The wide parking lane also provides space for bikers to travel outside of the moving vehicle lane. By providing this flexible space for prevalent behavior, NYC DOT intended to make the street more predictable. At major intersections with 135th and 145th street, where 250-300 drivers per hour make left turns, NYC DOT installed a left turn signal.

Location: New York, NY, Credit: NYC DOT

Location: New York, NY, Credit: NYC DOT


The redesign preserved the 10’ median island, but widened it at intersections to shorten crossing distances. Previously, the median had stopped short of the crosswalk. The redesign extended medians into the crosswalk with an additional 8’ in width on one or both sides of the median, creating 18’ or 26’ bulbs for pedestrian crossing refuges. To comply with Americans with Disabilities Act guidelines, the ramped median extensions have tactile warnings. NYC DOT first created the extended medians with paint, and in 2013 constructed some of the medians permanently, using concrete.

After the Phase 1 construction, NYC DOT collected data and presented an update to the community board. A November 2012 NYC DOT radar study found that 40% of drivers exceeded the speed limit of 30mph, down from 62% two years prior. The maximum recorded speed in November 2012 was 45 mph, an improvement from May 2010’s 52 mph. Though traffic counts increased by 35% to 34,044 vehicles per day, motor vehicle crashes decreased 32% on the segment of road covered in Phase 1.

Phase 2 Safety Improvements, implemented in 2013, covered the boulevard from 133rd to 110th Streets. The reconfiguration on this segment mimicked that of Phase 1, but engineers also preserved an existing bike lane between 110th and 118th Streets. Furthermore, Phase 2 addressed a problem intersection with especially dangerous pedestrian crossings. A two-block stretch of St. Nicholas Avenue cut diagonally across Adam Clayton Powell Jr. Blvd at 116th Street, resulting in a six-way intersection with a crossing distance of 150 feet at the northwest corner. The redesign expanded pedestrian space and added a painted curb extension, reducing that crossing distance to 92 feet. Similarly, the crossing distance between 115th and 116th Streets, formerly 115 feet, shrunk to 40 feet after NYC DOT added a painted curb extension that will eventually be built with concrete, as funding becomes available. At the intersection with 125th Street, Leading Pedestrian Intervals at traffic signals give pedestrians a head start crossing the boulevard. At other intersections, pedestrian countdown clocks allow people to gauge the walk signal’s remaining time. Community feedback indicated that pedestrians preferred to see the seconds counting down for as long as possible, so NYC DOT shifted the proportions, taking seconds from the “walk” signal and re-apportioning them to the “countdown” signal, while not changing the total crossing time. This provided pedestrians with more information, allowing safer, more predictable crossings.


NYC DOT implemented the project in coordination with other city agencies. NYC DOT worked with the Department of Sanitation to ensure that the new design would still accommodate street sweepers at medians and exterior curbs. The Fire Department reviewed designs to ensure no adverse effects to emergency response times. The Mayor’s Office for People with Disabilities provided feedback about the tactile pavers at medians.


The project cost $440,805 and was funded through the federal Congestion Mitigation and Air Quality Improvement Program (CMAQ).