The effectiveness of speed control humps on a range of five residential roads has been investigated. Details of construction and the effects of humps on accidents, flow, speed, pedestrians and residents are described. Humps were effective at these sites in reducing speed, flow and accidents whilst being acceptable to the majority of residents drivers. In some situations, however, part of the diverted flow was transfered to other residential roads causing a small increase in the number of casualities on the roads but this was not statistically significant.