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Basic Speed Law and Speed Limits
    "No person shall drive a vehicle on a highway at a speed greater than is reasonable and prudent under the conditions and having regard to the actual and potential hazards then existing."
    -Revised Code of Washington

A commitment to establishing speed limits is the foundation of the nationally recognized Basic Speed Law. This law focuses on the responsibility of drivers to modify their driving behavior in response to changes in roadway conditions. For more information on the actual speed limits in Pierce County, view our Speed Limits document.

Realistic Speed Zones are Desirable
Realistic speed zones preserve uniformity of speed, which reduces the possibility of conflict between faster and slower drivers and provides a higher level of safety. Uniformity of speed maintains consistency in traffic gaps and allows pedestrians and crossing traffic to more accurately judge the speed of oncoming vehicles. In addition, realistic speed zones provide law enforcement an effective enforcement tool by distinctly separating violators from the reasonable majority.

Citizens are more supportive of enforcement of reasonable regulations. Also, drivers are more likely to comply to the behavior of the majority and gives a clear reminder to violators.

Common Misconceptions About Speed Limit Signs
Speed limit signs do not influence traffic behavior to the extent that people commonly assume:
  • Speed limit signs don't slow the speed of traffic
  • Speed limit signs don't decrease the accident rate, nor increase safety
  • Higher posted speed limits don't cause higher traffic speeds than unposted limits
  • Posted speed limits don't ensure a safer roadway environment than unposted limits

In fact, studies have shown that most drivers will drive the speed suggested by roadway and traffic conditions regardless of the posted speed limit.

How Speed Limits are Determined
State law allows counties to set standard speed limits for roads where no limit is posted. Our county has set the standard limit at 25 miles per hour (mph). The speed limit for local roads is set at 25 mph. Higher speed limits for arterials are determined through traffic investigations.

Each arterial classification has a range of speed that is assigned on an individual basis. Major arterials tend to have a higher range of speed while collector arterials have a lower range of speed.

Within the established ranges, several factors determine the actual speed limit on a particular road:
  • Road surface and shoulder characteristics, grade, curves and sight distance
  • The 85th percentile speed, the speed at or below which 85 percent of traffic is moving
  • Influence of driveways, side streets and adjacent land uses along the road
  • Reported accident experience

The Pierce County Council officially adopts changes in speed limits into Pierce County Code. The speed limits are considered implemented when the speed limit signs are installed. The process includes public hearings and can take up to four months to complete.

Common Speed Limit Sign Locations

Arterials are signed by segment, which is a section of the road between two other crossing arterials. If a segment is longer than 1.5 miles, additional signs may be installed to remind motorists of the maximum speed allowed.

Speed limit signs are also installed on arterials where the speed limit changes and at points where traffic is leaving established 20 mph School Zones. Local roads are signed at entrances to neighborhoods so that drivers cannot come into an area without encountering a 25 mph sign.

Lowering the Speed Limit in Your Neighborhood

For local roads, a 25 mph speed limit is in effect. State law prohibits speed limits below 20 mph. We reserve 20 mph speed limits for:
  • Established school zones
  • Roadways within county parks and heavily used recreation areas

Use of the 20 mph speed limit in only these circumstances aids motorists in recognizing and reacting to these unique conditions. Our goal is to promote a safe roadway environment through consistent and realistic speed zones and signing procedures. Find out what can be done about neighborhood speeding concerns.