The National Academies

NCHRP 03-136 [Active]

Evaluating the Performance of Right-Turn-On-Red Operation at Signalized Intersections (with single and dual right-turn lanes)

  Project Data
Funds: $300,000
Staff Responsibility: Leslie C. Harwood
Research Agency: Iowa State University
Principal Investigator: Christopher Day
Effective Date: 8/13/2019
Completion Date: 6/13/2022
Comments: Research In Progress

Right-turn-on-red (RTOR) is permitted as an effective approach to reduce delay at signalized intersections, especially where there is a high volume of right-turn movements. The conflicting intersection movements of motorized and non-motorized users constitute a critical issue that affects both signal operation and safety. A method is needed to estimate the RTOR flow volume and its effect on delays because current RTOR estimates are not reliable for planning- or operational-level applications. Gaps in the Highway Capacity Manual (HCM) method include:
1. The lack of guidance on whether RTOR should be implemented or not.
2. The current signal timing model that does not adequately reflect the true operational effects of RTOR.
3. No volume estimation model for right-turn delay. The suggested default value for right-turn volume on red is 0 vehicles/hour, due to the difficulty in estimating it without the support of field data. This conservative estimate may lead to inaccurate performance estimations.
4. The pedestrian method that does not consider RTOR flow rate as an input nor does the existing RTOR guidance adequately consider non-motorized users.
As a result, agencies throughout the country have applied different RTOR techniques, which may lead to confusion. The development of an HCM method, therefore, will provide guidance on RTOR implementation, and the research findings will assist agencies and practitioners by providing a consolidated body of knowledge on RTOR analysis.
The objectives of this research are to (1) evaluate methods for evaluating right-turn-on-red (RTOR) at signalized intersections (right-turn configurations including shared, single, and dual right-turn lanes); (2) develop methods and tools that consider all modes and inform planning and operational decisions; and (3) provide potential modifications to standard references in the Highway Capacity Manual (HCM), NCHRP Report 812: Traffic Signal Manual, and the Manual on Uniform Traffic Control Devices (MUTCD).
The final report shall summarize the work performed on the previous tasks, along with significant conclusions and recommendations for implementation. It should include the following at a minimum:
         Methods for estimating RTOR flow rate;
         Methods for estimating the effect of RTOR flow rate on approach vehicular delays;
         Evaluation of any effects to motorized and non-motorized safety that may derive from the proposed methods.
         Recommendations on motorized and non-motorized criteria regarding the implementation of RTOR;
         Guidance for operations on both pre-timed and actuated signal controls;
         Case examples of the proposed method application; and
         Suggested modifications to standard references in the HCM, MUTCD, ITE: Guidelines for Determining Traffic Signal Change and Clearance Intervals, Traffic Engineering Handbook, and NCHRP Report 812: Traffic Signal Timing Manual, written in an appropriate format for review, revision, and concurrence for future updates and included as an appendix. 
Phase II interim report under review.

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