Leading Pedestrian Intervals (LPIs)

PurposeLPI Graphic.PNG

Provide pedestrians with a head start when crossing a signalized intersection.

Description

Leading Pedestrian Intervals (LPIs) are programmed into traffic signals to give pedestrians a 3-7 second head start. By providing pedestrians with a head start, the risk of conflicts between pedestrians and turning vehicles is reduced.

Safety Benefits

  • Increase visibility of crossing pedestrians.
  • Give pedestrians priority within the intersection.
  • Reduce potential conflicts between pedestrians and turning vehicles.

View locations where this tool is installed in Arlington County

Street Types and Context

Applicable Street Types

All street types with signalized intersections.

Other Location Guidance

  • Intersections where there is a high level of conflict between heavy turning traffic and pedestrians.
  • Intersections where there are heavy right or left-turn traffic patterns.
  • LPIs could also be applied as a leading bicycle interval for bikeway conflicts with turning traffic.

Primary User Groups

LPI Primary User Groups.PNG

Key Implementation ConsiderationsLPI Picture.PNG

  • Requires adjustments to existing signal timing.
  • LPIs should be accompanied by an audible noise to inform visually impaired pedestrians the WALK phase has started.
  • Installation of curb extensions at high conflict intersections can increase the effectiveness of LPIs and visibility of pedestrians.
  • At intersections with higher pedestrian traffic volumes, head starts of up to 10 seconds could be appropriate.

  • LPIs, in most cases, are installed in combination with “No Right Turn on Right” signage. The right turn restriction prevents cars waiting to turn right at the red light from using the gap created by the LPI, removing conflicts with the pedestrians in the crosswalk using the LPI. 

Expected Crash Reduction

LPIs have shown up to a 60% reduction in pedestrian-vehicle collisions at treated intersections (Fayish & Gross, 2010).

Cost

Typically, low to moderate cost. If new accessible pushbuttons or signals are specified, costs will increase.

Timeline

Timeline Icon.png

Less than one year, depending on complexity.

Application in Arlington 

Visit the Vision Zero Program:LPI to see where this tool has been implemented.

Vision Zero Dashboard

References

 

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