Road Safety

The Works Department has implemented many traffic and safety programs designed to improve road safety and efficiency. The Ontario Ministry of Transportation is a good resource to learn more about road safety.

The Canadian Safety Council has produced a video with the support of the Canadian Wireless Telecommunications Association entitled, "Driven to Distraction". This 10-minute video is a discussion on how we all might be safer drivers. To obtain a free copy of the "Driven to Distraction" CD, contact the Canada Safety Council by fax at 613-739-1566 or by email at csc@safety-council.org.

Durham Safety Improvement Program

For many years, road authorities, including the Region of Durham, have used collision rates as the benchmark for identifying problematic road sections and intersections. Collisions rates are a function of the number of collisions at an intersection or along a section of road and the volume of entering traffic. The use of collision rates has always been viewed with some scepticism as the volume of traffic can often skew the results.

In 2001, the Region of Durham Works Department completed work on an application that has replaced the use of collision rates and the resultant difficulties involved in identifying sites with potential for improvement. The Region of Durham's Safety Improvement Program (DSIP) is now the tool that identifies locations with a high degree of potential for safety improvement. The key differences between using the results of DSIP and collision rates are the inclusion of collision severity and the ability to compare locations to others with similar characteristics. DSIP uses a network screening process that is based on the Region’s collision database, traffic volume data, and a road inventory database for all road segments and intersections.

This process identifies sites with potential for safety improvement. The sites are ranked in descending order of their potential for safety improvement. The sites are then studied in conjunction with additional information, such as collision types and other factors; the aim being to determine the causes of the collisions, if any. The findings of this diagnosis are analysed and potential improvement measures are proposed. On the basis of effectiveness and the cost of implementation, it is possible to determine the most effective measure or combination of measures.

Traffic Operations Studies

Based on the results of the Durham Safety Improvement Program and/or other sources and requests, the Works Department undertakes traffic studies to confirm problems and identify solutions to traffic-related concerns. The studies can involve intersection control, signing, pavement marking, pedestrian activity, and collision investigations. The solutions improve the safety and efficiency of the road network.

Speed-Zone Studies

There is a common misconception that the greater the prevailing speed, the more dangerous the roadway. While it is true that a collision occurring at a higher speed is more severe than one that occurs at a lower speed, one of the biggest problems on our roads is the difference in travel speed. If every motorist drove at the same rate of speed, very few conflicts would result; however, as the range of speed increases, so does the chance of conflicts and thus, collisions.

One of the primary mandates of Traffic Engineers is to identify a safe, posted speed limit. Speed-zone studies are one of the tools used to determine if the posted speed limit is appropriate for the road environment, as the average speed is one of the best indicators of what motorists "feel" is the safe travel speed. Artificially lowering the speed limit creates greater speed variations, as the majority of motorists will continue to drive at the speed at which they are most comfortable. Installing signs is no deterrent to speeding, as enforcement is the key to ensuring compliance. The Works Department maintains an open line of communication with the Durham Regional Police Service to identify locations where enforcement will be beneficial, and contribute to a safe and efficient road network.

New Traffic Signals

The Region of Durham receives many requests during the year for new traffic signals, including intersection pedestrian signals [see photo]. Since the cost to install a signal is significant, and the impact on traffic flow can be detrimental, criteria are used to determine if the signal is warranted. The warrant criterion, as established by the Ontario Ministry of Transportation, is based on overall volume of traffic, delay to side street traffic, vehicles and pedestrians crossing the major road, intersection geometry and spacing and the collision experience over a three (3) year period. Warrants are used as a basis to prioritize potential candidate locations to ensure uniformity in the application of traffic control devices.

Traffic Calming

To reduce vehicular speed and/or traffic infiltration, traffic calming measures can be effective. Since a Regional road, by definition, promotes safe and efficient travel, "traffic calming" is typically contradictory. Traffic calming measures work best on lower speed roadways, such as minor collector roads and local residential streets. The Region of Durham constructs and operates arterial roads with posted speed limits based on the safe travel speed. Other than changing road characteristics/environment and enforcement, no other measure has proven to be effective at reducing average speeds.

Roadside Protection

Roadside protection is the engineering of the roadside to prevent vehicles from striking an immovable object within the clear zone, the area between the edge of the travel lanes and the lateral point to which an errant vehicle would encroach. When speeding, inclement weather, and many other factors come into play, there is an increased chance of vehicles leaving the roadway. Roadside protection, such as steel beam guide rail [see photo], is a tool to protect the motorists from immovable objects, unrecoverable slopes, etc., beyond the road.

Improving the relative safety of roadways from the standpoint of design relies on numerous factors. Engineers are continuously applying new techniques to make the next roadway safer than the last. However, there is no such thing as a completely safe roadway, open to traffic. Mobility, by its nature, involves an element of risk. As such, the treatment of roadside hazards is usually considered in the following order of preference:

  1. Remove the hazard.
  2. Relocate the hazard outside of the clear zone.
  3. Minimize the hazard by making it traversable or, in the case of sign supports, poles and posts, use crashworthy (breakaway) devices.
  4. Shield the hazard with barriers or energy attenuators.
  5. In the absence of other options, improve awareness of the hazard (positive guidance) through the provision of delineation or other warning devices.
  6. Reduce the posted speed limit.