California's "Basic Speed Law" states never drive faster than is safe for current conditions, regardless of the posted speed limit.
Maximum speed limit. The maximum speed limit on most California highways is 65 mph. However, for two-lane undivided highways and for vehicles towing trailers, the maximum speed limit is 55 mph, unless posted for a higher speed. On some highways the maximum speed limit is 70 mph, but only if there are signs posted showing 70 mph. All speed limits are based on ideal driving conditions.
Driving faster than the posted speed limit, or than it is safe for current conditions, on any road is dangerous and illegal.
When you drive too slowly. If you block the normal and reasonable movement of traffic by driving too slowly, you may receive a ticket.
When you drive a truck with three or more axles, you will be traveling slower than other vehicles. You must drive in the right-hand lane or in a lane specially marked for you. If no lanes are marked and there are four lanes in your direction, you may only drive in either of the two lanes closest to the right side of the road.
Special speed limits. Always drive more carefully near schools, playgrounds, parks, and residential areas. No matter what the speed limit sign states, you should never drive faster than 25 mph when the school ground has no fence and children are outside.
In business or residence districts the speed limit is 25 mph unless signs show other limits.
Slow to 15 mph for a blind intersection. Blind intersections are intersections where you cannot see for 100 feet in either direction during the last 100 feet before crossing. However, you may drive as fast as the posted speed limit if YIELD or STOP signs on the side streets give you the right-of-way.
The speed limit in an alley is 15 mph.
Speed and gasoline costs. If you watch your speed, you will save money. You can save gas if you drive at a steady, moderate speed. Start off slowly. Hot rod driving and quick starts decrease your gas mileage.
Never coast downhill in "neutral" to save gas. It is against the law because it is dangerous.