Ten roadside surveys of goods vehicles (over 3.5 tonnes maximum permitted gross weight) were conducted by TRRL between 1980 and 1986 on motorways and trunk roads in Great Britain. Over 12000 vehicles were weighed and photographed and each driver was interviewed. Eight per cent of these vehicles had gross weights greater than the permitted maximum (1.8 per cent by a margin of more than 5 per cent) and a further 5.4 per cent did not exceed the gross weight limits but had overloaded axles, bogies, tractors or trailers (3.9 per cent by a margin of 5 per cent or more). Overloading contributed directly to 5.7 per cent of the road wear attributable to all goods vehicles. The use of vehicles with plated gross weights greater than 32.52 tonnes was compared with that of 4-axle articulated vehicles (maximum plated weight 32.52 tonnes). Whilst the proportions of vehicles overloaded with respect to the gross weight limits were similar for these two groups, when axle and bogie overloading was also considered, overloading was greater for the heavier rated vehicles. The road wear associated with each tonne of goods moved by the heavier vehicles was lower than that for the lighter vehicles. The operations of foreign registered vehicles and of vehicles used to move heavy indivisible loads were also examined.

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