Setting Credible Speed Limits
February 13th, 2010Without doubt, the laws that drivers fail to follow the most often must regard the speed limit. Everyone has a justification for doing so. They range from being in a hurry, which is selfish, to the limit is set too low which is either a reasonable observation or a result of failing to take all factors into consideration.
In the past, speeds were set according to engineering design standards. This was often varied by the 85th percentile rule. The logic behind this was that the limit was most likely to be followed if it was set at what the majority of drivers chose.
More recently, collision data was introduced to the equation. A higher incidence of collisions called for a reduction in the speed limit. This will likely be supplanted by tending toward speeds that will mean road users will survive and injury will be minimized if a collision does occur.
What does the future hold? Perhaps we will factor in the production of greenhouse gases. Fuel consumption rises rapidly with speed and this is directly related to what comes out of the tailpipe.
Obviously, setting a credible speed limit that drivers will accept and follow is a difficult task. However, if it is accomplished there will be a high degree of voluntary compliance and perhaps a safer driving environment.
Cst. Tim Schewe (Ret) is the author of the Behind The Wheel column. He has been writing the column for most of the 20 years of his traffic enforcement service in the RCMP. In January 2006, Schewe retired from the force and resides in Vancouver Island. You can visit his website at http://www.drivesmartbc.ca/
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There are a few places where i think that the speed limit should be changed. Glenmore Trail is my biggest concern. It must be one of the few roads that the speed decreases when the road expands into a closed access highway. Then the speed limit increases when the road narrows, is in bad condition, and has multiple access roads leading into it. I have never understood why it does this, but it is freaking annoying.
I get that speed limits should be followed, but i am WAY more concerned about the people traveling under the speed limit than going over. A good example is Deerfoot Trial. Never have I understood why one car on the road needs to go 20km/h under the limit while everyone is going 10-20 over. When you look at the speed difference between the 2, you can understand why there are a lot of collisions on that damn road. There are signs everywhere that state the speed, tell slower traffic to move right, and say that no slow moving vehicles are permitted. You hear stories all the time of people being ticketed for speeding, but i haven’t heard of anyone being ticketed for going too slow. Would i be out of line when I say that i would like to see photo-radar vans ticket those going more than 10kms over the limit AND 10-20kms under? Do police ticket the guy holding up traffic in the far left hand lane? Speed uniformity and free-flow design of roads are the easiest way to combat high collision rates and ease congestion. When is the city of Calgary going to realize it?
agreed traffic lights are a big part of traffic congestion but drivers also play a major role. not paying attention when lights turn green, failing to yield to faster traffic, merging at drastically lower speeds then the rate of traffic, and even ignoring your surroundings cause traffic congestion. it’s everyone responsibility to keep traffic moving and everyone has the mentality to blame everyone else.
Changing driver habits is near impossible unless there is strict driver training enforced. for instance, if I get my license when I am 16, I do not have to go for another drivers test until i am senior. Imagine how often the rules change over a 40-year period. Not to mind that the privatized driver training programs seem to be handing out class 5 licenses like they are coming from cereal boxes. No wonder there are so many problems on the road!
There are only 2 options that i can see that could solve the problem:
1. Change road system designs to more free-flow design.
2. Re-structure licensing program
“speeds were set according to engineering design standards” if this is true than why aren’t speed limits being raised? Cars of today are engineered to a higher level take for example the stopping distance of today’s cars compared to cars just 15 years ago (significantly shorter). Also consider technological aids that are more and more often coming as standard equipment on new vehicles and continuously being improved; Traction Control, Stability Control, Electronic Brake Distribution, Smart All Wheel Drive, Antilock Brakes, Superior Tire Compounds….. These systems are not the end-all-be-all however they do help a vehicle’s handling. Also if speed limits were increased it would not be difficult for vehicle manufacturers to adjust the gearing of vehicles to improve fuel efficiency at the new higher speeds.
it’s ROAD engineering design standards, i.e. curvature radii, lane width, bank angles… not car standards
I think they mean the how fast the engineers intended the cars to be moving, ie. deer foot was designed for 125km/h, things like corner radius, ditches, guard rails, on/off ramps, hills and line of sight will affect this number.
like tomaz said many of todays drivers aren’t taught common sense so we’ll always see some dick doing 80kmh/ on deerfoor, rasing the speed limit would just allow the variation of speeds and collisions to be greater.