What speed limit is often found in narrow residential streets?

20 mph zones

Some traffic-calmed areas are indicated only by a 20 mph (32 km/h) speed-limit sign.

This speed-limit sign, in addition to advising the maximum speed, indicates that there may be traffic-calming features within the signed zone; these may not be individually signed.

You should drive at a steady speed within the speed limit, and avoid frequent acceleration and deceleration within these areas.