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.

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

Background (Show)

Lesson 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.

Lesson Comments

No comments posted to date

Comment on this Lesson

To comment on this lesson, fill in the information below and click on submit. An asterisk (*) indicates a required field. Your name and email address, if provided, will not be posted, but are to contact you, if needed to clarify your comments.


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

Lesson Contacts

Lesson Analyst:

Brian Philips


Average User Rating

0 ( ratings)

Rate this Lesson

(click stars to rate)

Lesson ID: 2010-00515