This paper describes work undertaken as part of a recent ARRB study that examined the relative effectiveness of a variety of sign types in slowing traffic from high speed (100 km/h) to low speed (60 km/h) at the approaches to rural cities and towns (see IRRD 849587). The different signs tested were: (i) an 80 km/h sign erected 300 metres in advance of the 60 km/h sign at the edge of the development (buffer zone); (ii) an advance warning sign comprising a 60 km/h sign with an `ahead' plate attached underneath erected 300 metres in advance of the 60 km/h sign; and (iii) different sized 60 km/h signs without additional signing. The sizes tested were B size (600 mm x 800 mm), C size (900 mm x 1200 mm) and D size (900 mm x 1200 mm) and D size (1350 mm x 1800 mm). Vehicle speeds were collected at each of five sites for each sign type and a detailed statistical analysis was then carried out. The study showed that: (i) none of the treatments was particularly effective at slowing traffic to 60 km/h as vehicles passed the 60 km/h sign, but use of either the advance warning sign or the buffer zone slowed traffic by a significantly greater amount than use of only a 60 km/h sign; and (ii) there was no significant difference in vehicle speeds measured when an 80 km/h buffer zone was installed compared to speeds measured when an advance warning sign was erected. (A)
Abstract