Leading Pedestrian Intervals and APS

A simple matter of equal access to a life-saving innovation.

  • Leading pedestrian intervals (LPIs) give pedestrians 3-7 seconds head start to begin their crossing before the parallel green light, increasing their visibility to turning cars.
  • This very low-cost measure can reduce vehicle/pedestrian crashes by 13-60% (Studies here and here), and is included in the FHWA’s list of Proven Safety Countermeasures: link.
  • Pedestrians who are blind or visually disabled use the sound of parallel traffic to identify the beginning of the Walk interval. They do not benefit from the additional crossing time if it is only communicated visually.
  • LPI’s delay the beginning of traffic movement, which can place blind pedestrians in front of turning vehicles, leave them without sufficient time to complete their crossing before the Don’t Walk signal, or even lead them to begin crossing after the Walk interval ends.
  • At LPI crossings, blind pedestrians can be expected to cross after the Walk sign has ended 15-38% of the time, and end their crossing in the Don’t Walk phase 40-82% of the time. (Link: “Leading Pedestrian Intervals at Urban Crosswalks: Effects on Safety for Travelers Who Are Blind” Bourquin, Bieder, Emerson, & Franck, 2023)
  • Accessible pedestrian signals (APS) communicate the Walk signal audibly and through a vibrotactile arrow button, removing ambiguity and providing blind and visually disabled pedestrians equal access to the benefits of the LPI.
  • The 11th edition MUTCD requires pedestrian signal heads at any crossing with an exclusive pedestrian phase or LPI with all conflicting vehicles stopped (section 4D.02), and supports the use of APS at these crossings (section 4I.06).
  • The ADA and Section 504 of the Rehabilitation Act require public agencies to make their services, programs, and activities accessible to people with disabilities.

We support the widespread use of leading pedestrian intervals, as long as they are paired with APS to provide their benefits to all pedestrians.