Regulations for Establishing Speed Limits

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Regulations for Establishing Speed Limits2021-03-22T02:52:42-07:00

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The issue of controlling the traffic speed has existed longer than the automobile itself.In the 1800’s, many cities had laws established to regulate the speed and flow of horse drawn carriages. Speed limits continue to be a frequent area of concern where we must balance the need for mobility, the desires of the majority of citizens, and the rules and regulations for establishing speed limits.

Many are surprised to learn that setting speed limits is heavily regulated by the State Legislature. Procedures and regulations for establishing appropriate speed limits are specified in the California Vehicle Code (CVC) and the pertinent sections are summarized in Table 1.

As you can see from the list of regulations below, setting speed limits can be complicated.  The need to comply with the approved procedures in establishing speed limits is driven by the need for enforcement.  When a driver disputes a citation in court, which they frequently do, the regulations prohibit the police officer from presenting evidence, such as a radar speed measurement, unless these complex regulations are followed.  Furthermore, the courts are prohibited from considering the evidence unless the speed limit was established in accordance with the statewide regulations.  Without properly established speed limits, scofflaws are quick to realize that they are nearly immune from enforcement and speeds are left uncontrolled.

Traffic rules account for most of an average citizen’s contact with law enforcement and the courts.It is important to establish traffic regulations that most drivers will choose to follow. Enforcement of laws that are widely perceived as unreasonable breeds disrespect and even contempt toward those who make and enforce those laws and the devices themselves.

Traffic rules and regulations are based on the concept of “voluntary compliance”. These rules must be fair and reasonable for responsible drivers, who are the majority, to choose to comply. This knowledge is based on many studies by organizations including the Federal Highway Administration, State Departments of Transportation, universities, professional organizations, and the insurance industry. These studies invariably find that drivers comply with those rules with which they agree and ignore those which they find unreasonable. These types of studies also continuously report that the speed at which a street is posted, has little effect on the typical speed of traffic on that street. Posting a lower, or higher, speed limit may result in an overall change in speeds of 2 MPH, which is imperceptible.



235Defines “Business District”
240Establishes procedures for determining residence and business districts
360Defines “Highways” as used in the CVC as including “Streets”
515Defines “Residence District”
627Establishes procedures for conducting “Engineering and Traffic Surveys”


22349Sets maximum speed limit of 55 MPH on two-lane highways, and 65 MPH on multi-lane highways, unless Engineering and Traffic Survey is conducted.
22350Establishes the "Basic Speed Law", which requires motorists to drive at a reasonable and prudent speed.
22352Establishes “prima facie” * speed limits of 25 MPH in business and residence districts, school zones, and near senior centers. Establishes 15 MPH speed limits at blind railroad crossings and intersections.
22357Allows local jurisdictions to raise a prima facie speed limit above 25 MPH (except in school and senior areas) upon the basis of an engineering and traffic survey.
22357.1Allows a 25 MPH speed limit adjacent to public playgrounds when children are present.
22358Allows local jurisdictions to reduce a speed limit from the 55 or 65 MPH maximum, on the basis of an engineering and traffic survey.
22358.5Establishes that physical conditions such as width, curvature, grade and surface conditions, or any other condition readily apparent to the driver, in the absence of other factors, do not require a reduction in the speed limit.


40801Prohibits police officer from using a speed trap for enforcement.
40802Defines the characteristics of a speed trap.
40803Prohibits the use of radar in a speed trap.
40804Disqualifies police officer from testimony if a speed trap is used.
40805Requires courts to adhere to speed trap regulations.

* “Prima facie” as used in the CVC means “at first sight”

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