Leading Pedestrian Intervals (LPIs)
Purpose
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
Key Implementation Considerations
- 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 highconflict 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.
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
Less than one year, depending on complexity.
References