APWA Book Review

North American Design Guidelines for Traffic Calming Measures
57 pp * 2006 * APWA

According to the APWA Transportation Committee, the purpose of APWA's publication North American Design Guidelines for Traffic Calming Measures is "to provide an easy-to-use, comprehensive and concise set of engineering procedures, including calming measure selection guidance information, for public works professionals. Much has been written with regard to traffic calming, so it has become important to provide local practitioners, who may not have the time for extensive research, the latest information and state-of-the-art standards in a format suitable for local government. This book provides tools for local decisions, explanatory tools for local elected and senior management officials by public works professionals, as well as guide local engineering designs, whether the work is done by in-house staff or consulting engineers."

In the spirit of improving the environment, promoting pleasant conditions for all road users and discouraging cut-through traffic, traffic calming measures are encouraged. The term "traffic calming" is often described as the combination of mainly physical measures that reduce the negative effects of motor vehicle use and improve conditions for non-motorized street users. However, the term "traffic calming" also applies to a number of transportation techniques developed to educate the public and provide awareness to unsafe driver behavior.

So, in the interest of the common good, the Transportation Committee came up with the idea of assembling the best practices in traffic calming in one publication called the North American Design Guidelines for Traffic Calming Measures.

The chapters in this full-color book cover:

  • Design Considerations - presents the general considerations that should be addressed when traffic measures are being considered and designed: grades, surface drainage, desired vehicle speed and streetscaping/landscaping, to name a few.

  • The ADA & Traffic Calming Issues - presents the issues under consideration by the Public Rights-of-Way Access Advisory Committee (PROWAAC) related to traffic calming measures. It is recommended these be implemented as a best management practices approach to new or retrofitted traffic calming facilities throughout North America.

  • Vertical Deflection - includes raised crosswalks, raised intersections, sidewalk extensions, speed humps and tables, and textured crosswalks. Reducing traffic speed is a more likely result of vertical deflections than is a reduction of traffic volume.

  • Horizontal Deflection - addresses the engineering principles that state the more acute the horizontal curvature of a traffic circle, chicane or curb extension, the greater number of motorists will reduce their speed.

  • Obstructions - traffic calming devices that intrude onto a roadway to reduce traffic volumes and/or traffic speeds. This chapter covers directional and full closures, diverters and star diverters, intersectional channelization, raised medians at intersections and right-in/right-out islands.

  • Traffic Calming Signs - these signs are the common usage signs to alert street users to traffic calming measures.

The purpose of this guide is to standardize the design procedures of traffic calming measures wherever possible in order to ease the implementation of effective traffic calming strategies in communities throughout North America. The information contained in this guide is not a strict set of standards because of certain instances where specifications may not be able to be met. The specifications presented are optimal, based on various research projects throughout North America, and should be used wherever it is possible and feasible to do so.

In addition to the above chapters, this full-color publication contains a glossary, online traffic calming resources and a selected bibliography. This document is intended as a best practices guide for North American traffic calming design and application when such measures are needed. It is presented as a general guide rather than a regionally specific set of codes or standards.

For more information on purchasing this publication and other American Public Works Association books, please call the APWA Bookstore at (800) 848-APWA, ext. 5254, or visit the bookstore online at www.apwa.net/bookstore.

Tim Haynes, APWA Transportation Committee member, contributed to this article.