California has a “Basic Speed Law.” This law means that you may never drive faster than is safe for current conditions. For example, if you are driving 45 mph in a 55 mph speed zone during a dense fog, you may be cited for driving “too fast for conditions.”
Regardless of the posted speed limit, your speed should depend on:
- The number and speed of other vehicles on the road.
- Whether the road surface is smooth, rough, graveled, wet, dry, wide, or narrow.
- Bicyclists or pedestrians walking on the road’s edge or crossing the street.
- Whether it is raining, foggy, snowing, windy, or dusty.
Maximum Speed Limit
The maximum speed limit on most California highways is 65 mph. You may drive 70 mph where posted. Unless otherwise posted, the maximum speed limit is 55 mph on a two-lane undivided highway and for vehicles towing trailers.
Other speed limit signs are posted for the type of roads and traffic in each area. All speed limits are based on ideal driving conditions. Construction zones usually have reduced speed zones.
High speed increases your stopping distance. The faster you go, the less time you have to avoid a hazard or collision. The force of a 60 mph crash is not just twice as great as a 30 mph crash; it’s 4 times as great!
Heavy Traffic or Bad Weather
You must drive slower when there is heavy traffic or bad weather. However, if you block the normal and reasonable movement of traffic by driving too slowly, you may be cited. If you choose to drive slower than other traffic, do not drive in the “Number One Lane” (fast lane) (refer to “Choosing a Lane”). When another driver is close behind you and wishes to drive faster, you should move to the right.
Towing Vehicles, Buses, or Large Trucks
When you tow a vehicle or trailer, or drive a bus or 3 or more axle truck, you must drive in the right most lane or in a lane specially marked for slower vehicles. If no lanes are marked and there are four lanes or more in your direction, you may only drive in either of the two lanes closest to the right edge of the road.