What is the default speed limit in a residential area unless otherwise posted?

In California, the default speed limit in residential areas is set at 25 mph unless there are specific signs indicating a different limit. This speed is established to enhance safety for residents, especially children, pedestrians, and cyclists who may be present in these areas. The 25 mph limit is also reflective of the need to allow drivers adequate time to react to sudden changes, such as a child running into the street or a vehicle backing out of a driveway.

Although there may be variations in speed limits in certain areas, such as school zones or places with heavier pedestrian traffic, the standard speed limit of 25 mph effectively balances the need for vehicle mobility with the safety requirements of residential communities. The other potential options, like 30 mph, 20 mph, and 15 mph, represent different contexts or specific zones but do not apply as the general rule for residential neighborhoods.