Form and minimum size of chicanes through which large fire engines can pass without difficulties were determined and their speed control effects were studied, in this paper. First, swept paths of a typical fire engine were drawn using a two-wheel-vehicle model and the length, lateral offset, and width of chicanes were determined. Second, several sets of chicane forms and sizes were selected and their speed control effects were investigated experimentally. When vehicle passes above photo-sensors stuck on road surface, the sensor sends electric signal to timer. Thus, the time when vehicle passed above the sensor was detected and vehicle speed was calculated. Measurements were repeated ten times for each chicane. It was found that the lateral offset of chicanes has greater effects on vehicle speed and that if the road is wide enough (width=5.5m), chicanes have few effects on speed.
