FHWA Accelerating Safety Activities Programs in Tennessee
By Airton G. Kohls
The University of Tennessee Center for Transportation Research presented a series of five free workshops in Tennessee where participants discussed the use of the Leading Pedestrian Interval (LPI) and the importance of Clearance Intervals at signalized intersections.
Sponsored with a grant from FHWA’s Accelerating Safety Activities Program, the workshops were presented in Chattanooga, Johnson City, Franklin, Memphis and Knoxville. A total of 77 people from 30 different government agencies and 11 different consulting firms participated in a collaborative round table discussion on how to improve intersection safety using LPIs and appropriate traffic signal clearance intervals.
Sources:
NCHRP Report 731, “Guidelines for Timing Yellow and All-Red Intervals at Signalized Intersections”.
FHWA and A. C. Fayish and F. Gross, “Safety Effectiveness of Leading Pedestrian Intervals Evaluated by a Before-After Study with Comparison Groups”, Transportation Research Record 2198 (2010).
The workshops were structured to instigate discussion by presenting videos of typical problems encountered at signalized intersections. First, the conflicts generated by vehicular traffic and vulnerable road users (pedestrians and bicyclists), promoted a dialogue on human behavioral issues, like the lack of attention to traffic control devices and non-yielding actions. Current research on LPIs informed participants of necessary considerations before and after applications, and videos from deployments in Sevierville and Chattanooga illustrated the Leading Pedestrian Interval concept. Later, the use of the ITE (Institute of Transportation Engineers) formula to calculate traffic signal clearance intervals, as well as detailed parameter recommendations were presented. Overall, the feedback from the presentations were very positive with agencies and consultants being appreciative of the effort and encouraging a similar 3-hour workshop format in the future.
Finally, we would like to recognize Jessica Rich from FHWA Tennessee Division Office, Kenneth Doyle from the city of Chattanooga, Anthony Todd from Johnson City, Adam Moser from the city of Franklin, Randall Tatum from the city of Memphis, Eric Itzel, Bryon Fortner and Joseph Dodgen from the city of Sevierville, Steve Bryan from TDOT and the Tennessee Traffic Signal Users Group (TTSUG) that collaborated to the success of this effort.
Before I go, here are some statistics and recommendations presented on a set of informational cards we prepared for these workshops:
What is LPI?
A leading pedestrian interval (LPI) gives pedestrians the opportunity to enter an intersection 3-7 seconds before vehicles are given a green indication. This “Advance Walk” indication allows pedestrians to establish a presence in the crosswalk, thereby increasing their visibility to drivers and potentially reducing conflicts with turning vehicles.
Recommendations for LPI implementation:
- Consider historical vehicle-pedestrian crash records, reported visibility issues, reported vehicle nonyielding behavior, and traffic and pedestrian volume;
- Evaluate potential increase in vehicular delay caused by LPI implementation. An LPI should be carefully considered if significant delay or congestion will be introduced;
- Consider implementation of an LPI for the whole day or on a time-of-day basis;
- Consider installing both static and blank-out “NO TURN ON RED” signs or “TURNING VEHICLES YIELD TO PEDESTRIANS” signs to enhance the effectiveness of the implementation;
- Educational and outreach activities also should be considered to allow the public to become familiar with the new LPI implementations;
- Field observations and evaluations are necessary after LPI implementation and adjustments should be applied to maximize LPI safety effectiveness and utilization.
