AP-G84/04 Best practice in road use data collection, analysis ... - WIM

Accessed by AR - ARRB TRANSPORT RESEARCH on 04 Feb 2005
Austroads 2004
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Best Practices in Road Use Data Collection, Analysis and Reporting
Figure 10 shows the distribution for six-axle Class 9 (‘123’) vehicles in all WIM sites surveyed. It
has two peaks, one at around 16 tonnes most likely for an unladen vehicle. Another peak is at 42
tonnes most likely for a fully laden vehicle (the maximum mass limit is 42.5 tonnes).
Figure 11 shows a similar bi-polar distribution of GVM distribution for B-doubles (‘1233’ or nineaxle
Class 10 vehicle). The first peak is at 26 tonnes and the second at 58 tonnes (the maximum
mass limit of a B-double is 62.5 tonnes).
Note that the y-axis showing the distributions were not scaled in the original document (Ramsay et
al. 2001). This omission is due to the sensitive nature of the data.
Peters (2002) showed similar results for all heavy vehicles entering and exiting the Port of
Fremantle in WA (Figure 12). He also reported that 8% of six-axle vehicles, 13% of B-doubles and
4% of double road-trains were overloaded. The majority of overloading occurred on the in-bound
route into the Port. The degree of overloading varied and static weighbridges are needed for
enforcing compliance.
Distribution of ’123’ vehicles
0 10 20 30 40 50 60 70 80
Gross Vehicle Mass (t)
Figure 10 – Total mass of three-axle prime movers and three-axle semi-trailers
(Source: Ramsay et al. 2001)