Document Type

Article

Publication Date

2022

DOI

10.33492/JRS-D-21-00062

Publication Title

Journal of Road Safety

Volume

33

Issue

2

Pages

56-73

Abstract

Left turn crashes can impact the safety of the drivers due to the speed and angle at which they occur. Left turns are specifically reported to affect older drivers more than the other types of crashes. This paper provides a review of the existing engineering countermeasures that have been evaluated to improve driver safety at left turns. Twenty- eight studies on left turn signal displays (protected left turns, flashing yellow arrow, and digital countdown timers), intersection geometry (offset left turn lanes, diverging diamond interchange, roundabouts, exit lanes for left turn, left turn bay extension, and contraflow left turn lanes), and driver warning systems (infrastructure warning systems, and in-vehicle warning systems) are reviewed. Eighteen studies were evaluated in the field, nine in laboratory environments, and one online. All countermeasures demonstrated varying levels of effectiveness. We found protected left turns, roundabouts, and warning systems to be the most effective engineering countermeasures. Advantages and disadvantages of each countermeasure and research shortcomings of the evaluation studies are discussed. Review findings may help practitioners and researchers guide more effective countermeasures for left turns for older drivers.

Comments

© The Authors 2021

This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.

Original Publication Citation

Samuel, S., Singh, A., & Yamani, Y. (2022). Engineering countermeasures for left turns at signalized intersections: A review. Journal of Road Safety, 33(2), 56-73. https://doi.org/10.33492/JRS-D-21-00062

ORCID

0000-0001-8990-0010 (Yamani)

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