In late 1993 Perth's main gateway from the east, Greenmount Hill was the site of a serious accident involving a 64 tonne heavy combination vehicle (HCV). A primary investigation suggested the use of arrester beds as a means of capturing such runaway vehicles; however, no data to support the use of such beds by HCVs was available. Trials were carried out in 1994 using two arresting mediums, a synthetic aggregate (Lytag) and a natural laterite gravel. A number of vehicle configurations were trialed, ranging from an unladen semi-trailer of 18 tonne gross vehicle mass to a 79 tonne Double Bottom Road Train and with entry speeds up to 112 km/h. Results demonstrated the potential for direct entry beds to capture all vehicles trialed, with no significant difference between Lytag and laterite gravel arresting materials. Vehicle configuration and overall length as well as the number and spacing of axles influenced the overall bed effectiveness. Mean deceleration varied depending on entry speed, with vehicles showing a tendency to plane at higher speeds and in the denser laterite gravel arresting material. (A)
Abstract