This paper summarises the main results of on-road trials of speed cushions in 1993, at four schemes in Sheffield and York, England. Speed cushions were used as traffic calming measures on residential roads with bus routes, whose traffic flows were between 800 and 4000 vehicles per day. The cushions were installed about 50m to 100m apart, and various cushion layouts were tested, sometimes combined with chicanes, carriageway narrowings and humps. The trials aimed to compare the performance of various cushion designs, together with their positioning within carriageway narrowings and chicanes. Some results are presented for: (1) overall speed reductions; (2) effects of cushion dimensions and layout on mean speeds; and layout on mean speeds; (3) effects of distance between cushion layout; (4) effects on driver behaviour and parked vehicles; (5) effects on buses and emergency vehicles; and (6) effects on cyclists and motor cyclists. Although it is too early to quantify accident savings, a 50% reduction in accident frequency seems possible on roads using wider cushions.
Samenvatting