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Few resources provide information related to selecting the most appropriate traffic signal phasing for the various geometric and operational situations encountered in the field. This is especially true for left-turn signal phasing decisions with respect to the level of control for the left-turn movement and whether left turns should precede or follow the main through movement.

The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 284: Decision-Making Guide for Traffic Signal Phasing is designed to give professionals designing or operating signalized intersections the tools they need to provide safe and efficient overall operations, considering both crash risk and movement delays.

Suggested Citation

National Academies of Sciences, Engineering, and Medicine. 2020. Decision-Making Guide for Traffic Signal Phasing. Washington, DC: The National Academies Press.

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Publication Info

83 pages |  8.5 x 11 |  DOI:

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