The National Academies

NCHRP 17-109 [Pending]

Crash Modification Factors for Automated Traffic Signal Performance Measures

  Project Data
Funds: $400,000
Contract Time: 30 months
Staff Responsibility: Roberto Barcena


Automated traffic signal performance measures (ATSPM) offer an alternative approach to traditional signal timing. ATSPM have been shown to help state departments of transportation (DOTs) and local transportation agencies improve operations at signalized intersections through reduced split failures, arrivals on red, red light running, and delays.


The right-of-way time allocated to different modes and movements can significantly impact behavior – drivers willing to take smaller gaps, pedestrians waiting for the walk signal, or bicyclists clearing an intersection. While not a true adaptive solution, ATSPM allow agencies to make near-real-time adjustments based on data from the field.


Research is needed to assist DOTs and local transportation agencies with quantifying the safety benefits and reductions in crash frequency and severity resulting from the deployment of ATSPM signal timing and developing crash modification factors (CMFs)

The objective of this research is to develop CMFs for ATSPM signal timing for all modes and various conflict types and severity.

The accomplishment of the project objective will require at the minimum the following tasks.
Phase I - Planning
Task 1. Literature review of research related to the development of CMFs for ATSPM and other traffic signal technologies. The review shall include published and unpublished research conducted through national, international, state, and pooled-fund sponsored research as well as the literature generated within the public sector. Targeted surveys of agencies and practitioners should be considered to learn about the status of practice and current challenges.

Task 2. Identify the required data to be collected in Phase II to achieve the research objective.

Task 3. Synthesize Tasks 1 and 2 to identify the knowledge gaps related to ATSPM and related CMFs, and the data availability and quality. These gaps should be addressed in this research as budget permits or in the recommendations for future research.

Task 4. Propose a methodology to achieve the research objective, to be fully developed in Phase II. At the minimum, Task 4 shall include proposed methodologies to:

  • Develop a detailed plan to collect and evaluate the data necessary to achieve the research objective, including how to address any identified deficiencies in the available data or encountered problems with the data collection effort;

  • Analyze the collected data to develop CMFs;
  • Quantify the benefits and associated costs for the deployment of ATSPM signal timing and develop safety benefit/cost ratio case studies. The case studies shall be approved by NCHRP; and

  • Develop a roadmap for possible inclusion in the AASHTO Highway Safety Manual or Crash Modification Factors Clearinghouse. The roadmap should consist of a strategy including goals, necessary steps and their timing, and a rationale for its deployment.

Task 5. Prepare Interim Report No. 1 that documents Tasks 1 through 4 and provides an updated work plan for the remainder of the research no later than 6 months after contract award. The updated plan must describe the process and rationale for the work proposed for Phases II and III.

Phase II – Development of Methodology

Task 6. Execute methodology proposed in Task 4 according to the approved Interim Report No.1.
Task 7. Prepare Interim Report No. 2 that documents Task 6 and provides an updated work plan for the remainder of the research. The updated plan must describe the process and rationale for the work proposed for Phase III.
Phase III – Final Deliverables
Task 8. Develop and conduct webinars to present the CMFs and other key findings of the research to the AASHTO Committee on Transportation System Operations, AASHTO Committee on Safety, and the AASHTO Technical Committee on Roadside Safety.
Task 9. Revise the presented materials to the AASHTO committees taking into account feedback gathered during the webinars and submit a recorded webinar as a deliverable.
Task 10. Prepare final deliverables including: (1) conduct of research that documents the entire research effort, (2) the recorded webinars from Task 8, (3) a stand-alone technical brief for the use of ATSPM and related CMFs, and a roadmap for possible inclusion in the Highway Safety Manual or Crash Modification Factors Clearinghouse, and (4) a stand-alone technical memorandum titled “Implementation of Research Findings and Products.”

Proposals have been received in response to the RFP.  The project panel will meet to select a contractor to perform the work.

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