Intersection collision avoidance systems deployed at intersections with high crash frequencies or high rates of severe injury are projected to recoup initial costs within one year, through a reduction in crashes.

September 2003
Statewide,California,United States; Statewide,Minnesota,United States; Statewide,Virginia,United States

Summary Information

In 2003, a research project was conducted to define and evaluate infrastructure-only Intersection Collision Avoidance System (ICAS) concepts aimed at reducing the number of intersection crashes. System engineering analyses were performed to define and evaluate the feasibility and effectiveness of alternative infrastructure-based advanced technology concepts. This included development of functional requirements, conceptual designs, and testing the feasibility of those designs at high crash intersections in three states.

A literature review of human factors studies, crash studies, and countermeasures identified to reduce intersection crashes was conducted. The review resulted in a general description of crossing path crashes at intersections and the factors causing those crashes. The project identified certain parameters required for characterizing traffic flow based on current Intelligent Transportation Systems (ITS) applications/concepts for traffic management. Information on human factors issues important to the selection and design of infrastructure-based technology was identified. These included the driver age, vehicle gap acceptance, and response to emergency events.

The contractor worked closely with Virginia, California, and Minnesota (The Infrastructure Consortium) to select high-priority candidate intersections where the feasibility of different ICAS concepts could be evaluated. Crash reports for crashes at candidate intersections were analyzed to identify types of crossing path crashes that were occurring and potential causes of those crashes. It was determined that Left Turn Across Path of Opposite Direction (LTAP/OD); Straight Crossing Path (SCP); and Left Turn Across Path of Lateral Direction (LTAP/LD) crashes were the most frequent types of crash, regardless of whether or not the intersection was signalized.

Operations concepts were developed based on crash scenarios and causal factor patterns obtained from crash reports for the candidate intersections. Six of the original candidate intersections were chosen for further study to determine the feasibility of implementing an ICAS at each location. Data were collected on-site for each intersection. Based on that data, conceptual designs for an ICAS were developed to address the crashes observed at each intersection. Based on this work it was determined that implementing an ICAS to address each of the three most prevalent types of intersection crashes was feasible.

In addition, the benefit-cost analysis showed recouping of ICAS implementation costs to be quick. For example, intersection collision avoidance systems deployed at intersections with high crash frequencies or high rates of severe injury are projected to recoup initial costs within one year, through a reduction in crashes. These benefits are calculated using a benefit cost analysis (BCA) where the measure of potential benefit assumes a 100% reduction of applicable crashes. If a more realistic effectiveness rate of 50% reduction of applicable crashes is assumed, it is projected to take less than one and half years to recoup the initial ICAS costs.


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Intersection Collision Avoidance Study

Author: Battelle

Published By: U.S. Department of Transportation Federal Highway Administration, Office of Safety

Source Date: September 2003

EDL Number: 14105

Other Reference Number: FHWA-JPO-05-030


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Goal Areas


Related Metropolitan Integration Links

Link 25: Incident Management intra-component

Typical Deployment Locations



Intersection Collision Avoidance System, ICAS

Benefit ID: 2008-00573