Speed zones are often taken for granted until a problem arises. The following information will help you understand how speed zones are established, and what they can and cannot do.

Speed Zone Myths
Citizens frequently ask why we don't lower the speed limit in problem areas. Before and after studies have found no significant changes in speeds after posting new speed limits. There is no direct relationship between posted speed limits and accident frequency.

Did You Know? Despite the myths, speed limit signs do not slow the speed of traffic, reduce accidents or increase safety. Fact - Most drivers drive at a speed that they consider to be comfortable, regardless of the posted speed limit.

Speed Laws
All fifty 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. These speed limits do not need to be posted to be enforced.

What is prima facie? Prima facie (pronounced PRY-muh-FAY-shee; -shuh) is a Latin term meaning "at first appearance" or "obvious." Driving faster than the speed limit is "prima facie evidence" of unreasonable speed.

Prima facie limits include:

• 25 MPH in business and residential districts
• 25 MPH in school zones when children are present
• 15 MPH speed limit in alleys, at intersections and railroad crossings
• 15 MPH where visibility is very limited

Speed limits between 25 and 55 MPH are established on the basis of traffic engineering surveys. These surveys include an analysis of roadway conditions, accident records and a sampling of the prevailing speed of traffic. A safe and reasonable limit is set at or below the speed at which 85% of the drivers drive.

Benefits of Speed Limits
Traffic flowing at a uniform speed results in fewer accidents. Drivers are less impatient, pass less often, and tailgate less, which reduces both head-on and rear-end collisions.

The posting of the 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 asked to enforce and defend unrealistic and arbitrary speed limits.

Residential Streets 25 MPH speed limit signs may be posted on residential streets without conducting a speed survey. A local street which is not designated as an arterial or collector on the Federal System Map or in the City's Circulation Element per Section 40802(b) and 22352(b)1 of the California Vehicle Code, may have its residential streets posted at 25 mph. In order for a street to be designated as a local street on the City's Circulation Map and Federal System Map, the street needs to have the following characteristics: The width cannot exceed 40 feet. The interrupted length cannot be more than 1/2 mile; interruptions include official traffic control devices such as stop signs and traffic signals. There can be no more than one traffic lane in each direction.

Arterial Streets: Arterial streets are typically multi-lane roadways (existing or planned for the future) serving commercial and business land uses, carry the major traffic flow throughout the City and connect City streets to the State Highway or Freeway system. The speed limit on arterial streets are required to be posted based on speed surveys. Typical speed limits on arterial streets are 35 to 55 mph.

Collector Streets: Collector streets typically conduct local street traffic to the arterial street system. There are a number of streets in the City which are designated collector streets in order to receive Federal funds for maintenance. Although these streets are of a residential nature, they are not local streets and do require speed limits to be posted based on speed surveys. Typically, the streets have speed limits of 30 mph to 40 mph.

Questions?
If you have questions, requests or suggestions concerning traffic contact Public Works at 916.625.5500 or by email at Access Rocklin.