Benefit-to-cost ratios for buses equipped with pedestrian warning systems were baselined at 28:1.

Experience with a bus-based pedestrian warning system in Portland.

May 2015
Portland; Oregon; United States

Summary Information

This project evaluated the benefits and costs of transit vehicle turn warning systems designed to improve safety for pedestrians in Portland. As part of a cooperative agreement with the Federal Transit Administration (FTA) the Tri-County Metropolitan Transportation District of Oregon (TriMet) equipped 45 buses with three types of commercially available auditory warning systems, and installed an infrastructure-based warning system as a prototype at a crosswalk. The bus-based system used auditory messages and LED directional lighting on the forward side of each bus to improve driver visibility and alert pedestrians at intersections on five bus routes. The system was activated automatically when bus speed profiles and steering components met pre-defined thresholds on each bus route. The infrastructure-based system used pedestrian detection and intersection signal control systems to activate BUS blank-out signs. As a prototype, these warning signs were mounted on pedestrian signal heads at the intersection of SW 5th Avenue and W Burnside Street. When a pedestrian was detected and a bus was approaching from the turn lane, the word "BUS" was displayed on the blank-out signs as a warning. Evaluation data were collected over a seven month period from March to September 2014. Bus drivers and pedestrians were surveyed, and focus groups were conducted to assess perceptions and overall satisfaction with the technologies deployed. Additional research was conducted to assess impacts on pedestrian behavior. Data were collected from in-vehicle sensors and cameras.

Benefit-to-Cost Analysis

Benefits and costs were evaluated to assess deployment and lifecycle O&M costs and the associated benefits to society in terms of improved pedestrian safety. Since incidents involving pedestrians were relatively rare events, safety impacts and associated monetary benefits of improved safety were derived from assessments of changes in pedestrian behavior, and the likelihood of close call events and fatalities before and after warning systems were installed. The benefit-to-cost analysis was organized around a benchmark (baseline), upper bound, and lower bound scenarios, whose ranges reflected uncertainties associated with warning system costs, bus-pedestrian outcome frequencies, and the monetization of benefits. Outputs from the analysis included net present values, benefit-cost ratios, and internal rates of return. The time frame for the benefit-to-cost analysis was set at 12 years and the discount rate for the analysis was set at seven percent.


All of the scenarios modeled yielded net positive benefits. The associated internal rate of return was estimated at 34 percent which translated into a payback period of approximately three years. The baseline benefit-to-cost ratio was estimated at 28:1. The table below provides additional detail from the analysis.

A. Installed Cost
B1. Annual Maintenance Cost
B2. Present Value Maintenance Cost
C1. Annual Avoided Fatality Benefits Cost
C2. Present Value Avoided Fatality Benefits
D1. Annual Avoided Injury (transport) Benefit
D2. Present Value Avoided Injury (transport) Benefit
E1. Annual Avoided Minor or No Injury Benefit
E2. Present Value Avoided Minor or No Injury Benefit
F. Present Value Benefits (C2+D2+E2)
G. Present Value Costs (A+B2)
H. Net Present Value (F-G)
I. Ratio of Benefits to Costs (F/G)
J. Internal Rate of Return

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Evaluation of Transit Bus Turn Warning Systems for Pedestrians and Cyclists: Draft Final Report

Author: Pecheux, Kelley (AEM); James Strathman (PSU); and Jason Kennedy (AEM)

Published By: U.S. DOT Federal Transit Administration (FTA)

Prepared by Applied Engineering Management Corporation for the FTA

Source Date: May 2015

Other Reference Number: Report No. 0084



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Benefit ID: 2015-01002