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Bicycles/Pedestrians

Safety Toolbox: Engineering


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Turn restrictions

   
Signs are placed prohibiting right turns on red (RTOR) at signalized intersections (on one-way streets, this could involve prohibiting left turns on red).  The restrictions may apply all day or only during certain hours. In addition to signs, a curbed island can be used to restrict left turns from side street approaches onto the street where marked crosswalks are located.
objective To reduce the number of turning movements conflicting with pedestrians using the crossing.
applications Usage is based on the history of pedestrian collisions with turning vehicles or heavy pedestrian traffic.
target population All Pedestrians, Motorists
crash type Pedestrian R/W Violation-Intersection, Pedestrian Violation-Intersection, Traffic Signals and Signs, Improper Turning
advantages
  • Reduces conflict between turning vehicles and pedestrians in the crosswalk
  • Protecting pedestrians from left-turning drivers can reduce the potential for collisions
  • The potential for broadside collisions is greatly reduced
  • Traffic volumes on the side street may be reduced in the proximity of the intersection. This type of island design is not so restrictive to traffic flow as a solid median with a cut-through for pedestrians
disadvantages
  • Can increase vehicle delay. This can be mitigated by part-time turn prohibitions that are displayed using changeable message signs.
  • Enforcement is difficult
  • Traffic may reroute to other intersections, which can cause impacts to other streets.
pointers The island does not provide a true refuge for pedestrians because left turns from the median in the center of the major street into the side streets are still permitted. In order to discourage drivers from going around the end of the island to make a left turn from the side street onto the major street, the adjacent noses need to overlap. This can make it more difficult for pedestrians to use the crosswalk, especially for a person in a wheelchair. Therefore, when used with a crosswalk, a gap is retained, again making the island more susceptible to driver violations.
cost Low to Medium, approximately $200 per sign; $2,000 per variable message sign; High, $25,000-$35,000 per turn island location, depending on the length and size of the island used.
responsibility Public Works, Police Department
further reading

Zegeer, C.V., and M.J. Cynecki. Increased Safety at Right-Turn-on-Red Intersections. 1997 Annual Meeting Compendium of Papers, 190-194. Washington, DC: ITE, 1997

Zegeer, C.V., and M.J. Cynecki. Evaluation of Countermeasures Related to RTOR Collisions That Involved Pedestrians. Transportation Research Record 1059:24-34, 1986

Zador, P., J. Moshman, and L. Marcus, Adoption of Right Turn on Red:  Effects on Crashes at Signalized Intersections, Accident Analysis and Prevention 14 (1982), pp.219-234

Retting, R.A., M. Nitzburg, C.M. Farmer, and R. Knoblauch. Field Evaluation of Two Methods for Restricting Right-Turns-on-Red to Promote Pedestrian Safety. Washington, DC: Insurance Institute for Highway Safety, April 2001.
examples City of Philadelphia, PA; New York City, NY; City of Atlanta, GA.
related tools Curb Extensions, Reduced Curb Radii

Index: alphabetical / cost / crash type / target population

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