Implement infrastructure-based collision avoidance technology to mitigate risks at crash prone intersections.
A research project based on literature reviews and working with Virginia, California, and Minnesota.
Made Public Date
02/10/2010

124

California
United States

966

Virginia
United States

17

Minnesota
United States
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Identifier
2010-00515

Intersection Collision Avoidance Study

Background

In 2003, the U.S. Department of Transportation sponsored a research project 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.

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 was 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.

Lessons Learned

This research project that was conducted to define and evaluate infrastructure-only Intersection Collision Avoidance System (ICAS) concepts, produced a number of important findings and lessons learned, as presented below.

  • Consider implementing an infrastructure-based collision avoidance technology to mitigate the risks to stakeholders.
  • Implementing infrastructure-based collision avoidance technology is one method to mitigate the risks (to government agencies, manufacturers and drivers) of deploying in-vehicle and cooperative technologies. Implementing infrastructure-only components (e.g., roadside signs, vehicle sensors, modifications of existing traffic control devices, etc.) will demonstrate the potential benefits of intelligent collision avoidance technology. Then, the infrastructure-only systems can be enhanced and updated to support in-vehicle and cooperative technologies.
  • When investigating the feasibility of implementing infrastructure-based collision avoidance technology, incorporate testing of motorist response to roadside communication devices.
  • To test for feasibility of implementing a countermeasure concept at each of the six candidate sites in the study, vehicle data (turning times, free-flow speeds, braking rates, refused gaps) were collected to determine if the intersection met the requirements of the suggested concept. The data showed that at all of the six candidate intersections, the suggested concept was feasible, based on the vehicle data collected on site. However, motorist response to roadside communication devices still requires extensive testing, as this is a critical requirement of several concepts in this research study.
  • When testing the feasibility of Intersection Collision Avoidance Systems (ICAS) concepts, carefully consider the main causal factors for crashes.
  • 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 was 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.
  • Conduct human factors research before adopting collision countermeasures.
  • Collision countermeasures were developed based on crash data analyses. This project showed that implementing infrastructure-based intersection collision avoidance technology is feasible and can be cost effective. But effectiveness of each measure on preventing crossing path crashes is still undetermined. Motorist response time to and acceptance of dynamic roadside communication devices is the last major requirement unmet. Accordingly, significant human factors research must be conducted before the proposed countermeasures are adopted.

The knowledge and experience from this research project demonstrate that implementing an ICAS to address each of the three most prevalent types of intersection crashes was feasible. Accordingly, this work also provides evidence for the feasibility of infrastructure-only Intersection Collision Avoidance System (ICAS) concepts. It also provides evidence that the approach of implementing an infrastructure-only Intersection Collision Avoidance System (ICAS), and then enhancing and updating it to feature in-vehicle and cooperative technologies, is a sound one.

Intersection Collision Avoidance Study

Intersection Collision Avoidance Study
Publication Sort Date
09/01/2003
Author
Battelle
Publisher
U.S. Department of Transportation Federal Highway Administration, Office of Safety

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Goal Areas

Focus Areas Taxonomy: