Speed Limit Increase

What do speed limit increases actually do?

Evidence that I've seen confirms my suspicion, that increasing speed limits that are too low, does not influence significantly the actual traffic speeds, instead having mostly beneficial effects. The 85th percentile defines what's "too low".

Despite many engineering (i.e. rigorous) studies, the safety extremist movement would have you believe that higher speeds are bad in any circumstances: http://www.safety-council.org/info/traffic/speed.html

Since they provide not a shred of evidence, but mostly unrelated data and assumptions, find below all the "evidence" I could find, time permitting.


Wikipedia articles on speed mention and have linked many studies, see http://en.wikipedia.org/wiki/Speed_limit

Saskatchewan '04



  • On June 1, 2003 the maximum speed limit on select sections of Saskatchewan twinned highways was increased from 100 km/hr to 110 km/hr.
  • Data collected at the study sites before the increase indicated that the 100 km/hr speed limit was well below the average driver speed and 85th percentile speed.
  • Data collected after the speed limit increase showed only a minimal increase in average driver speeds, 85th percentile speeds, and pace speeds, while the average increase in speed differential was found to be minimal.
  • The speed limit increase appears to have created a higher driver compliance rate, at least in the short term.
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