How are speed limits set?
Speed limits are often taken for granted and, until a problem arises, most people pay little attention to them. When traffic problems occur, concerned citizens frequently ask why we do not lower the speed limit. There are widely held misconceptions that speed limit signs will slow the speed of motorists, reduce collisions, and increase safety. Most drivers drive at a speed which they consider to be appropriate, regardless of the posted speed limit. "Before and After" studies have shown that there are no significant changes in average vehicle speeds following the posting of new or revised speed limits.

Traffic engineers and police officers examine many traffic and road conditions to determine a reasonable speed limit. Speed studies are performed to determine the 85th percentiles speed, or the speed that 85 out of 100 vehicles travel at or below. Other conditions evaluated include number and type of crashes, number of cars, pedestrians, and bicycles, along with physical conditions of the road such as sidewalks, hills, curves, lanes, driveways, intersections, roadway surface, and traffic controls.

Generally speaking, a safe and reasonable limit is set at or below the speed at which 85% of the drivers drive. Posting an appropriate speed limit simplifies the job of enforcement officers, since most of the traffic is voluntarily moving at the posted speed. Blatant speeders are easily spotted, safe drivers are not penalized, and patrol officers aren't expected to enforce unrealistic and arbitrary speed limits.

For more information about speed limits, click here.

Show All Answers

1. How do I know if the stop light has a problem, or if I am doing something wrong?
2. How can I locate my property corners?
3. Are the Cascade Avenue crosswalks really safe?
4. What's the difference between a Court and a Circle, or a Drive and a Road?
5. Are marked crosswalks safer than unmarked crosswalks?
6. Why are roundabouts used instead of a signal light?
7. Why can't we see through the roundabouts in River Falls?
8. Why doesn’t the city use Children at Play signs?
9. Why don't they put in more stop signs to reduce speeding?
10. How are speed limits set?