Leading Pedestrian Interval (LPI)

DEFINITION AND DESCRIPTION

When it is not feasible to remove or relocate a roadside obstacle, it may be shielded by a longitudinal traffic barrier or crash cushion. A roadside barrier redirects or contains errant vehicles. Examples include guardrail, cable rail, and concrete barriers. 

Barrier end treatments (e.g., anchorages, terminals, crash cushions) are modifications installed at the ends of roadside or median barriers.

The Crash Modification Factor (CMF) Clearinghouse contains several CMFs for adding new guardrail along embankments. Guardrail installations can reduce run-off-road injury crashes by up to 47% and fatal crashes up to 44%.

Implementation Categories

CONSIDERATIONS

• Refer to Section 4I.06 in the MUTCD for guidance on LPIs.
• Requires pedestrian signal heads.
• LPIs can be provided automatically with each phase or only when actuated.
• In the absence of Accessible Pedestrian Signals (APSs), visually impaired pedestrians may wait during the LPI and cross when they hear vehicles begin to move.

APPLICATION

• Recommended where high volumes of turning traffic conflict with high volumes of crossing pedestrians.
• Prioritize installation at crosswalks frequented by school-aged children or older adults.

example

Complimentary Countermeasures

• Centerline Turn Hardening
• High-Visibility Crosswalks
• Lighting
• Roadway Narrowing — Curb Extensions