Speed Limits

Speed limits are often taken for granted and, until a problem arises, most people pay little attention to them. The following information will help you understand how speed limits are established, and what they can and cannot do.

All 50 states base their speed regulations on the Basic Speed Law:

"No person shall drive a vehicle . . . at a speed greater than is reasonable or prudent . . . and in no event at a speed which endangers the safety of persons or property."

Under California law, the maximum speed limit in urban areas is 55 mph. All other speed limits are called prima facie limits, which are considered by law to be safe and prudent under normal conditions. Prima facie limits established by State law are as follows:

  • 55 mph is the maximum speed limit in urban areas
  • 25 mph is the speed limit in business/residential districts and school zones (with children present)
  • 15 mph is the speed limit in alleys, railroad crossings, and intersections - where visibility is limited

How are speed limits determined between 25 and 55 mph?

Speed limits are established on a basis of traffic engineering surveys. These surveys include an analysis of roadway conditions, accident records, a sampling of the prevailing speed of traffic, amount of side traffic access, and traffic volumes.

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.

How can I get a speed limit sign placed on my street to slow traffic?

The most common misconception about speed limits is that putting up a sign will slow the speed of traffic, reduce accidents, and increase safety.

The truth is, most drivers drive at a speed that they consider to be comfortable and safe, regardless of the posted speed limit. The County of Shasta does not usually install signs on most residential streets, but instead relies on the California Vehicle Code 25 MPH limit. Studies have shown that there are no significant changes in average vehicle speeds following the posting of new or revised speed limit signs.  Furthermore, there is no direct relationship found between posted speed limits and accident frequency.

However, there are ways to slow down drivers on your street:

Increased Enforcement: This requires an officer to ticket those drivers driving at excessive speeds.

Speed Monitoring Awareness Radar Tool (Smart Trailer): Access to a radar device, mounted on a small trailer, is available to clock vehicles and exhibit their speed on an oversized display board. The device has helped control chronic speeding problems by letting motorists know when they are exceeding the limit. This device is set up by the Sheriff's Department upon request and availability.