Eight-tonners on decrease
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SE of vehicles of under eight ns gross weight is on the crease, says Mr A. W. awthorne, head of the mnsport and Road Research tboratory's engineering vision.
Economic pressures were fluencing the manner in hich the carriage of an creasing yearly tonnage was !ing met by road transport, r Crawthorn, told a meeting ' the FTA's Greater London 'vision.
The number ot vehicles ing licensed over the eightn gross mark was on the increase and would probably carry on growing.
Environmental and social influences were consideradons to be taken into account for the design of vehicles for the future.
On the environmental front, it would be desirable to reduce the noise levels for those working on the vehicle and those living alongisde the road.
Research at TRRL, MIRA and Southampton University, had shown this to be a practical proposition.
In experiments using sound absorbant material to enclose the engine and gearbox, redesign of the crankcase — plus improved silencing — reduced the noise level in the cab to a point where normal conversation could take place and at the road side was reduced by 10 dba.
Tyres play a large part in the overall contribution to vehicle noise, radial tyres with a highway pattern being the least offensive.
Fuel consumption was a very complex subject with many variable factors to be considered, including environments route and driver.
As far as the vehicle was concerned, streamlining and the use of airofoils for head on reduction in drag could help . _ but there was still a lot of work to be done in this area.
The automatic gearbox could be used to advantage in the fight to reduce fuel consumption. Low tyre pressures added to the drag on the truck so it was important that they kept the correct pressures. The work being done on _ suspension design was as yet incomplete, but the indications were that a soft suspension would cause less damage to the road surface.
On the safety side, there was still a lot of room to improve commercial vehicle brakes.
Under some circumstances a lorry could take up to twice the distance of a car to come to a halt.
Much of this was attributed to the tyres which were designed for a long life and this conflicted directly with the grip needed to give short stopping distances.
The meeting concluded with questions from the floor. One that was raised several times and seemed to interest the speaker more than most related to the ergonomics, from the safety angle, of loading a commercial vehicle.
As little research work had been done in this area, Mr Cawthorne promised to refer it back to his colleagues at TRRL.