Pedestrian Scramble

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Overview


The Pedestrian Scramble (a.k.a. Barnes Dance or exclusive pedestrian timing) is a traffic signal phasing scheme in which pedestrians are given their own signal phase to cross in any direction, including diagonally through the intersection. The Pedestrian Scramble is an example of a pedestrian signal innovation, which in this case has two objectives:
  1. to reduce or eliminate conflicts between vehicles and pedestrians;
  2. to allow intersections to operate more efficiently when large pedestrian volumes prevent vehicles from being able to make turns.

At traditionally signalized intersections with high pedestrian volumes, crossing pedestrians may severely limit turns and cause intersection back-ups. The Pedestrian Scramble is not used widely in North America, but has made a comeback as traffic innovations to increase pedestrian safety have been pursued more consistently since the mid-1990’s.

History

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The Pedestrian Scramble has been in use in North America since the 1940’s, but attained its greatest popularity during the 1950’s and 60’s through the advocacy of Henry Barnes, a prominent traffic engineer who served as traffic commissioner in several U.S. cities, including Denver, Baltimore, and New York City. During this period, it became known as the “Barnes Dance.”[1]

Benefits

Early studies showed the Pedestrian Scramble can reduce pedestrian crashes by 50 percent at intersections with high pedestrian volumes and low vehicle speeds and volumes.[2] A series of locations in Beverly Hills recorded a 66 percent drop in pedestrian-vehicle conflicts. However, studies in Israel of low-volume sites with few crashes found that scrambles made little difference in conflicts and crashes . If applied in the right locations, there are very few pedestrian treatments available that can achieve the level of safety benefits associated with Pedestrian Scrambles.

Another significant benefit is that the Scramble can greatly enhance the efficiency of the intersection, in effect adding capacity without the need for road-widening, new signals, or other expensive and disruptive treatments. This is possible in both low-volume and high-volume traffic situations.[5]

Challenges

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  1. With an exclusive pedestrian phase, pedestrians are forced to wait through two or more vehicle phases.
  2. There must be adequate signage and pavement markings to ensure pedestrians understand they are required to wait; otherwise pedestrians may continue to block certain vehicle movements and the efficiency benefits will be lost.
  3. If the wait is intolerably long, pedestrians will cross whenever there is a gap. This is not only less safe, but the long wait is perceived by pedestrians as being unfriendly to them – exactly opposite of what is intended.[3]
  4. Another challenge of the pedestrian scramble is that it is confusing for pedestrians with visual impairments, since the audible cues associated with surging parallel traffic streams are no longer a cue to proceed. This makes it difficult to know when to begin crossing, or may actually introduce a new danger for the visually impaired pedestrian who is unaware of the exclusive pedestrian phase. For these reasons, clear signage and appropriate audible cues or recorded messages should also be installed.
  5. The Scramble may also eliminate the ability to synchronize timing with adjacent traffic signals.

Oakland Example

A study of a Pedestrian Scramble in Oakland, California, shows the results and trade-offs that might be expected after installing this scheme. The UC Berkeley Safety Center’s examination of the pedestrian scramble at Webster and 8th revealed three key findings:
  • Pedestrians were accepting of the Scramble system.
  • They understood the new system and generally followed it.
  • The Scramble resulted in decreased conflicts between pedestrians and vehicles.
  • After the Scramble was installed, there was an increase in pedestrian violations. Specifically, pedestrians who grew tired of waiting crossed against the pedestrian wait signal, in the “safe direction”, parallel to vehicle traffic.
The UC Berkeley investigators recommended monitoring the Pedestrian Scramble over time to ensure vehicle-pedestrian conflicts were reduced and that these were associated with real reductions in pedestrian injuries and fatalities.

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REFERENCES

Each source is referred to by the same number every time it is cited. Please keep citation style consistent.
[1] Source: http://www.barrypopik.com/index.php/new_york_city/entry/barnes_dance/
[2] Zegeer, C.V., K.S. Opiela, and M.J. Cynecki, 1983. Pedestrian Signalization Alternatives, Report No. FHWA/RD-83-102, Federal Highway Safety Administration, Washington, DC.
[3] Van Houten, Ron et al., 1997. Field Evaluation of a Leading Pedestrian Interval Signal Phase at Three Urban Intersections, Insurance Institute for Highway Safety, Arlington, VA, April 1997.
[4] Allyson K. Bechtel, Kara E. MacLeod, and David R. Ragland, "Oakland Chinatown Pedestrian Scramble: An Evaluation" (December 17, 2003). UC Berkeley Traffic Safety Center. Paper UCB-TSC-RR-2003-06. http://repositories.cdlib.org/its/tsc/UCB-TSC-RR-2003-06
[5] UC Berkeley OnLine Newsletter, Winter 2005-2006 http://www.tsc.berkeley.edu/newsletter/winter05-06/scramble.html.

PICTURE REFERENCES

Pictures are cited in the order they appear above. Please keep citation style consistent.
[1] Pasadena, CA, scramble. Courtesy of Andy Hamilton.
[2] Courtesy of PEDSAFE, Federal Highway Administration, US Department of Transportation.
[3] Courtesy of PEDSAFE, Federal Highway Administration, US Department of Transportation.

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