Traffic calming : have we given everyone the hump, or is it just a load of chicanery ?

This paper outlines the history of traffic calming, and discusses some of the traffic calming projects introduced in the county of Kent in England. Kent County Council (CC) developed its first traffic calming sites in 1987, but was always critical of the original 4m long 100mm high blacktop 'rollover' hump. It soon developed the lower, more user-friendly 'flat-topped' or 'Kent-style' road hump. As the number of clamped areas expanded, Kent CC developed other types of scheme, including: (1) one-way ramped narrows, with traffic having to give way at alternating pinch-points; (2) half and full chicane on primary and secondary roads in rural villages and on some urban streets; and (3) an urban safety management project covering a zone with 3500 houses. Although these schemes reduced speeds by up to 10mph, accidents by up to 80%, and through traffic by 30-50%, many residents considered that the schemes adversely affected their local environment; criticisms also came from bus and emergency services. As a result, Kent CC conducted trials of specialist vehicles over various forms of traffic calming. Humps and ramps were then flattened, and further alternatives sought. Calming schemes using only horizontal deflections are now being applied to main roads passing through small towns and villages.