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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883


Setting speed limits

I think we have all experienced speed limits that seem unreasonably low (45 mph “forever” leaving south Colfax, for example).  On the other hand, I occasionally encounter a limit high enough to make achieving it a challenge, and unsafe if you do (75 mph through the curves on I-90 west of St. Regis, MT).

Wondering about area speed limits, reader M.P. wrote, “I have driven the 395 route on a regular basis for 28 years.  The question arises from time to time:  Why when the speed goes from 50 to 45, then eventually 35 then 30, how does the DOT determine those speeds?  I have no problem with the 50 but the 45 seems too fast.  I have seen several accidents in that speed zone and many near misses.  I also notice that many cars and trucks slow to below 45 in much of that stretch due to all the people turning into businesses and driveways and roads.  It seems that stretch needs to be 35, not 45.  Very rarely does anyone go over 45 unlike the 35 and 30 zones where they go 5 over on a regular basis.  Has anyone else mentioned this situation?”

I have spoken of speed limit creation with Al Gilson (WSDOT Communications Manager, 509 324-6015) in the past. Limits are ultimately set, reduced, or increased by the Secretary of Transportation.  If state engineers, or local authorities within given city limits, determine on the basis of an engineering and traffic investigation that the speed limit is greater or less than is reasonable and safe under the conditions found to exist on a given roadway or part of one, increases or decreases are made.

They likely consider many safety issues, such as average speed tendencies, accident data, traffic volume, road configuration, traffic control devices, number of cross streets, and other surrounding characteristics, in making determinations.

I agree that the limit for the section of Division Street M.P described seems a bit fast (45 mph).  When I have driven that stretch over the years, however, I find that I can rarely attain that speed; it seems that the average actual speed driven there is more like 35-40 mph, so maybe the authorities feel that it’s self-regulating.  As M.P. wrote, it’s rare to see anyone exceeding the limit at that spot.  It would be interesting to see if any recent traffic studies have been done there; one would have to contact Al Gilson or Spokane city traffic engineers to find out.

Other times, drivers think speed limits are too low when they are not.  An example of that is the required 20 mph at school zones.  I conclude that many drivers believe 20 mph is too slow in those zones since so many of them exceed the limit there.

Numerous drivers are apparently experiencing time issues or are simply having difficulty operating their vehicles that slowly.  But here’s a good reason for the 20 mph limit in school zones:  children are present!

Excited and distracted kids are not always watching for vehicles, so it is important for drivers to do so.  Driving at 20 mph allows drivers to be more vigilant in school zones.  And besides that, in the event of human/vehicle collisions, survival rate of the human is exponentially better when the vehicle is travelling 20 mph than even at 25 mph.

One other location where humans are prevalent adjacent to traffic is in construction zones.  Statistical data reveals that these workers are in peril when exposed to the general motoring public.  That’s why speed limits are reduced in such zones, and why the fines for speeding infractions are doubled and mandatory when committed there (same for school zones).

In most normal driving locations (not special speed zones), the average flow of traffic tends to be 3-5 mph over the limit.  My experience is that the DOT and law enforcement understand this, and are generally tolerant of those averages.

Nevertheless, I learned a long time ago that a surefire way to avoid speeding tickets is to observe the speed limits.  The side benefit is enhanced safety and longevity for you and those within your driving proximity.

Readers may contact Bill Love via email at