The use of road humps for the control of traffic on residential streets

With greater interest being centred on the management of traffic in residential areas, to improve both safety and amenity, many authorities are showing great interest in the use of road humps as a means of slowing or diverting traffic. This paper brings together much of the recent Australian Road Research Board work on road humps. Matters of legal liability are discussed, and a series of controlled tests is described which established the suitability of a hump, 100 mm high by 3.7 M long (in direction of vehicle travel), for trials on Australian public roads. The results of these on road trials generally confirmed the suitability of the device, with both speeds and volumes being considerably reduced in the treated streets. Residents, and to a lesser extent road users, agreed that humps were effective and served a useful purpose. The loading of the road structure in the vicinity of the humps has been examined and load increases found to be only modest when compared to an untreated street with a rough surface. The work carried out in Australia has provided considerable input for the development of warrants as well as to both device and installation design, all of which is outlined in the paper. Although the general efficacy of road humps has been established, they are a severe form of traffic control device and the paper concludes by pointing out that humps should only be considered when all other forms of traffic control have been explored, and only then within the context of an overall traffic management scheme for the area concerned. The development of such a scheme will often remove the need for humps in favour of some less extreme solution (a).