Pedestrian Response to Leading Pedestrian Intervals: The Role of Visual and Audible Cues in Start-Up Time and Walking Speed

Pedestrian fatalities in traffic crashes have increased steadily since 2009, highlighting the urgent need for improved pedestrian safety measures. Among various engineering interventions, the Leading Pedestrian Interval (LPI) has been introduced at signalized intersections to enhance pedestrian safety by activating the pedestrian walk signal before the start of the vehicular phase. While there is widespread agreement regarding the potential safety benefits of LPIs, researchers and practitioners have yet to reach a consensus on their optimal duration, with recommendations typically ranging from 3 to 7 s. This study evaluates the effectiveness of a 3-s LPI on pedestrian behavior at seven intersections managed by the Sacramento County Department of Transportation. The analysis examines the influence of visual and audible signal configurations on pedestrian start-up times and walking speeds. Data were collected before and after the implementation of the LPI, revealing that the majority of pedestrians did not reach the midpoint of the initial travel lane until 1–2 s after the vehicular green signal. Our findings indicate that the inclusion of audio cues significantly reduced pedestrian start-up times, whereas countdown signals detracted from LPI effectiveness by reducing pedestrian walking speeds. These results offer valuable insights for transportation agencies considering the implementation of LPIs and emphasize the necessity of integrating both visual and audible signals to enhance pedestrian safety at signalized intersections.