Last week, when we were interviewed by The Province News I was told by the reporter that our methodology sounded “too theoretical” or “radical”. Let us be clear there is nothing new, radical or theoretical about the proper setting of speed limits. If you want proof, you do not have to go far to find it. Two brief examples are set out below. Is there any place more conservative than Republican stronghold Arizona?

After you are done reading their speed limit setting methods, please check out BC’s very own speed limit review, that was commissioned in 2002, and see what the engineers told your provincial government.

From the Arizona Dept. of Transport Website concerning Establishing Speed Limits:

Speed zoning is based upon several fundamental concepts deeply rooted in our American system of government and law.

  1. Driving behavior is an extension of social attitude, and the majority of drivers respond in a safe and reasonable manner as demonstrated by their consistently favorable driving records.
  2. The normally careful and competent actions of a reasonable person should be considered legal.
  3. Laws are established for the protection of the public and the regulation of unreasonable behavior on the part of individuals.
  4. Laws cannot be effectively enforced without the consent and voluntary compliance of the public majority.

Public acceptance of these concepts is normally instinctive. However, the same public, when emotionally aroused in a specific instance, will often reject these fundamentals and rely instead on more comfortable and widely held misconceptions, such as:

  1. Speed limit signs will slow the speed of traffic.
  2. Speed limit signs will decrease the accident rate and increase safety.
  3. Raising a posted speed limit will cause an increase in the speed of traffic.
  4. Any posted speed limit must be safer than an unposted speed limit, regardless of the traffic and roadway conditions prevailing.
“Before and After” studies consistently demonstrate that there are no significant changes in traffic speeds following the posting of new or revised speed limits. Furthermore, no published research findings have established any direct relationship between posted speed limits and accident frequency, although short-term reductions have resulted from saturation enforcement efforts directed at speed and other traffic law violations.
And the following straight out of the independent review of speed limits commissioned by our very own BC provincial government in 2002:
Maximum speed limits enhance the safety objective by placing an upper limit on speed choice,
and to reduce the differences in vehicle speeds by drivers using the same road at the same
Based on years of experience and observation, the following fundamental concepts have been
used to establish realistic speed zones.
The majority of motorists drive at a speed they consider reasonable, and safe for road,
traffic, and environmental conditions. Posted limits which are set higher or lower than
dictated by roadway and traffic conditions are ignored by the majority of motorists.
The normally careful and competent actions of a reasonable person should be
considered legal.
A speed limit should be set so that the majority of motorists observe it voluntarily and
enforcement can be directed to the minority of offenders.
A speed limit should seem too fast for a majority of users or it is not a maximum limit.
A driver’s choice of speed can impose risks on other road users. Crash severity
increases with increasing speeds because in a collision, the amount of kinetic energy
dissipated is proportional to the square of the velocity. Crashes, however, appear to
depend less on speed and more on the variation in speeds. The likelihood of a crash
occurring is significantly greater for motorists traveling at speed slower and faster than
the mean speed of traffic.
As shown in Figure 1, maximum speed limits should be set for ideal road, traffic, and
environmental conditions. Drivers should adjust their speed for conditions that are less
than ideal, as shown in Figure 2.
Establishing safe and realistic uniform speed zones is important because it invites public
compliance by conforming to the behavior of the majority of motorists and provides a clear
reminder to violators.
It also assists the courts by providing a guide as to what constitutes a
reasonable and prudent speed and reduces arbitrary enforcement and conviction tolerances.
Furthermore, it ensures that the requirements and intent of Provincial and local laws and
ordinances are met.