Dynamic weigher asses the test
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THE DYNAMIC weigher, tested on the Staines by-pass, meets the desired performance for enforcement of weight limits under the Road Traffic Acts, and would be an asset for any enforcement authority.
This was the conclusion of a report to the Department of Transport by the Surrey Trading Standards Department, this month.
Six Weighwrite weighers were tested during the summer and autumn to give experience under differing climatic conditions.
The vehicles used — 12 in all — range from a two-axle lightweight boxvan to a fiveaxle articulated tipper with twin steering axles on the tractive unit; some had semiautomatic gearboxes.
A five-axle Army transporter with a three-axle trac tive unit and two-axle drawbar trailer grossing 36.70 tons also figured in some of the tests.
After proving the gross weight of the vehicles on a static weighbridge of known accuracy, the vehicles were weighted statically on the Weighwrite equipment and then checked by 10 test runs at 2.2mph in the dynamic mode, followed by two test runs at speeds in excess of 2.2 mph to check that the equipment printed the overspeed runs in red.
Specification for the equipment allowed a tolerance of plus or minus 50kg per axle but regulations to be framed for the use of the equipment for enforcement purposes envisages a tolerance of plus or minus 100kg per axle.
The tests, therefore comprised a number of runs with each vehicle, taking into account both tolerances at the laid down speed of 2.2mph and at higher speeds.
The tests at the laid down speed at the lower tolerance showed accuracy of up to 98 per cent within specification; in some cases 100 per cent accuracy with specification was achieved.
Operators can take some comfort in the fact that where the equipment deviated from that performance the weights shown were lower than the checked weights in the main.
The DTp told CM this week that it was encouraged by the results of the Surrey trials but would not make a firm decision on the use of the equipment till the results of the trials still being conducted at Barham, in Kent, were known; possibly about March.
Nevertheless, preparation of draft regulations under Section 14 of the Road Traffic Act 1974 were going ahead on the assumption that the results of the Barham trials would be equally satisfactory.
Both the Road Haulage Association and the Freight Transport Association have been represented at the Staines site to see how the trials were progressing.