This paper discusses the effectiveness of sight distance reduction on speeds at vertical and horizontal alignment on urban local roads in Melbourne. The evaluation was done in two phases. The first phase investigated speeds on thirteen crests of vertical curves while the second phase investigated speeds on three long and flat roads. The speed measurements were conducted using ARRB Transport Research's Vehicle Data Acquisition System (VDAS). The Road Geometry Data Acquisition System (RGDAS) was also used to measure sight distances on vertical curves. The results on speed and sight distance on vertical alignments showed that sight distance reduction was not effective in speed reduction. The design speed to design speed to satisfy the sight distance requirements for a car to see an approaching car was exceeded at thirteen sites by the 85th percentile speeds and at eight sites by the mean speeds. The design speed to satisfy sight distance requirements for a car to see a stationary object was exceeded at eleven sites by the 85th percentile speeds and at four sites by the mean speeds. The conclusion from the study of sight distance and speed on urban local roads is that speed reduction may be better achieved by more traditional traffic engineering means. (A)
Samenvatting