California's speed laws can be found in the state Vehicle Code. Section 22350 is the Basic Speed Law, which states that California drivers may not drive faster than is "reasonable and prudent and in no event at a speed which endangers the safety of persons or property."  How do you know what speed is "reasonable and prudent?" Sections 22348 through 22413 of the Vehicle Code establish "reasonable and prudent" speed limits for various types of roads. These default speed limits are also known as prima facie speed limits. For example, the maximum speed on most California highways is 65 miles per hour. On a two-lane, undivided highway the speed limit drops to 55 mph. The prima facie speed limit is 15 miles per hour in alleyways and approaching blind intersections or railroad crossings. It's 25 miles per hour in near schools or senior centers.

However, the prima facie speed limits can be altered as appropriate to fit local conditions. This is usually done through an engineering and traffic survey, where the speed that people naturally drive a particular stretch of road is measured. The government generally tries to set the speed based on the speed that 85% of drivers are traveling at or below-the goal is to set a speed limit that is both safe and comfortable for the majority of drivers. So, while it can be useful to know the default speed limits listed above, it's more important to keep an eye out for the posted speed limit signs.

It's also important to remember to adjust your speed based on conditions such as weather and traffic. Posted speed limits are maximum speed limits for ideal conditions. If conditions are less than ideal and you do not adjust your speed accordingly, you can still get a speeding ticket for violating California's Basic Speed Law.