Traffic Calming Design Guidelines

Tim Haynes
Engineering Assistant IV
City of Regina, Saskatchewan
Member, APWA Transportation Committee

For the past few years or so, we have heard stories of people dying in car and motorcycle accidents caused by excessive speed. We have read stories of neighbourhood streets used as diverters of main arterials by drivers who re-route to avoid traffic congestion. This trend has influenced city administrations to take such actions as initiating traffic calming studies which will offer illustrated solutions to the excessive speed scenarios.

There are many engineering ways of traffic calming. Most are costly and require some kind of construction. The typical "engineered" solutions are:

  • Speed humps or bumps
  • Traffic circles for residential streets
  • Curb extensions to reduce the crosswalk distance and choke the width of the street
  • Traffic diverters (one-way, do not enter, and local traffic only signs)
  • Chicanes (type of traffic choker by inducing a curb in the street)

Although in some cases the engineered solution might be necessary, sometimes residents themselves may be able to solve some of the problems.

The problem begins when people try to make it home as fast as possible when they are in driver mode. Funny, isn't it, how we ask of others to slow down when we are in resident mode. People's historical retreat from residential streets began when parents started to take kids off the streets because of the speed of traffic. This retreat was an open invitation for drivers to speed...and it was followed by residents parking their cars in their driveways in order to protect their automobiles, which resulted/induced even more speed. Guess what then happened to streets that are now highway wide and car-interference free?

Parents became wary of their kids' safety using the sidewalks, so they brought them to their destination, using their cars, on empty streets, at high speed.

When I was a child I used to play hockey, baseball and soccer in the street. These days, residential streets are mostly empty. Reclaiming these streets lies in actions such as traffic calming—by sending a message to speeding drivers that this street is a residential street and as such it has a living community.

There are two factors that can induce drivers to slow down. You'll probably relate to this; the first is uncertainty and the second is something that will take brain power or require particular attention.

When I drive I must admit that, although very aware of my surroundings, I'm pretty focused on my destination. However, if there are children playing in the street, if there is an unusual event, a traffic jam around a school at the end of the day from parents picking up their kids or cars parked on both sides of the street causing a narrow funnel or a chicane, it makes me slow down right away. The idea is that if drivers engage traffic calming measures mentally while driving on your street, they will slow down.

It is without a doubt that if you retreat from the street, it will speed up traffic and people will stop using it as a play area, cycling or go for walks. On the other hand, if you induce interference and uncertainty, traffic will slow down, the community life will increase and it will continue to slow the speed of the traffic. The city's or municipality's role is to assess problems and to take action if an engineering solution is necessary. The driver's role is to slow down and respect other neighborhoods.

So in the spirit of improving the environment, promoting pleasant conditions for all road users and discouraging cut-through traffic, we encourage traffic calming measures.
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.

Traffic calming techniques often differ; techniques include police enforcement and education only in some areas. In others, it means the employment of speed humps only, while in others it means the possible use of a wide array of techniques and devices.

So in the interest of common good the APWA Transportation Technical Committee came up with the idea of assembling the best practises in traffic calming in one publication called the Traffic Calming Design Guidelines.

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.

One of the fundamental steps in designing a traffic calming program is to ensure that solutions are installed where they are most needed and can be most effective in improving neighbourhood safety. With cities receiving so many requests it's hard to determine which neighbourhood the city should work with first. One solution that many municipalities are using is a point system to determine where products should be implemented. The first step in employing a point system is to conduct a traffic study to determine which streets have the highest traffic volume, speed, and safety concerns.

Once streets are identified, the point system involves ranking each of the streets with a point value based on local priorities. Examples of the types of information that are ranked include whether the street generates pedestrian traffic; proximity to a school, park, church, or store; presence of a bike lane or bus lane; and volume of traffic.

By assigning different point values to specific indicators, community officials can clearly assess and rank a street's need for calming solutions based on distinct number values. Streets with the highest scores are identified as program priorities. This allows cities to focus on those streets with the greatest safety needs.

Once the highest ranking streets are chosen, there are two options a traffic calming program can choose. The first is to advance directly to installing permanent products based on information from the ranking system. The second is to test temporary solutions to assess their effectiveness and which products are most appropriate for the targeted streets.

According to the Transportation Committee, the purpose of APWA's publication of Traffic Calming Design Guidelines "is to provide an easy-to-use, 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 will provide 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. APWA is an international organization, and these tools are intended to be suitable for all APWA members worldwide."

At the APWA Congress this year the Traffic Calming Design Guidelines will be unveiled at a Transportation Committee educational session. If you have a need or require traffic calming information, be sure to attend this session. You can also stop by the Congress Bookstore to check out the new publication.

Tim Haynes is the Project Chair of the Traffic Calming Design Guidelines publication project. He is a current member of the APWA Transportation Committee, a Past President of the Saskatchewan Chapter, and a past Chair of the chapter's Newsletter Committee. He can be reached at (306) 584-8265 or thaynes@regina.ca.