In which area is it common to find a 20 mph speed limit?

A 20 mph speed limit is commonly found in school zones because this speed limit is designed to enhance safety for children and pedestrians in areas where they are likely to be present, such as near schools during drop-off and pick-up times. Lowering the speed limit to 20 mph helps to decrease the stopping distance for vehicles and gives drivers a better chance to react to unexpected situations, such as children crossing the street. This is particularly important since children may not always be aware of their surroundings and may run into the street unexpectedly.

Additionally, while residential areas and park entrances may also have lower speed limits, they typically do not specifically have a standard limit of 20 mph enforced as consistently as school zones. Highways, on the other hand, generally have much higher speed limits due to their design and intended use, which is focused on facilitating faster traffic flow.