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MANY large tractive units on Britain's roads today are plated for gross train weights of 38 and 40 tonnes. Among them are Volvo F86 — Ford Transcontinental — Scania 110— Mack — DAF 2800 — Leyland Marathon. Stand these against any 32-tonner and the difference is almost impossible to detect.
In the recent past there has been a vociferous anti-lorry lobby stirring up public opinion against the heavy goods vehicle. Their word pictures describing the hgv have produced varying degrees of emotive expression, from concern to panic.
Those who have allowed themselves to be influenced are not confined to little old ladies who run tea rooms in the Cotswolds, hill farmers in Wales or game keepers in the Grampians. The anti-lorry campaign has spread to District and Regional Councils, the Back Benches at Westminster and, who knows, it may soon reach the Cabinet Room.
Small increase
The time has come for facts: an increase in gross weight need not increase a vehicle's dimensions. Nor need the point load per wheel increase. One more axle with a 10-tonne loading limit will more than cater for the additional 8-tonne load on a 40-tonner.
The axle can be added to either tractive unit or trailer and this is where the marginal extra length enters the scene. If the extra axle is fitted to the tractive unit an increase in length must inevitably follow. Nevertheless, the amount of this increase will be relatively small at around 0.5m (19in). All this increase will do is to allow the vehicle manufacturers to fit proper sleeper cabs to the six-wheel units while still retaining full articulation between tractive unit and trailer.
To the man in the street then, the larger tractive unit will remain virtually indistinguishable from present 32-tonners. If the proposal is not to specify a tractive ratio of 3.5' then the extra axle could easily be fitted to the semi-trailer. In this case almost certainly there would be no increase in the total length of the tractor/trailer combination.
The reasons for this are simple. At present the standard 1S0 container lengths are 6.1m (20ft) and 12.2m (40ft) so an increase in platform length here would be superfluous. Most goods which are not transported by container do not occupy the full load space anyway, so again a longer platform would not really be necessary.
Finally, and from a cost point of view this is probably the most important. reason, loading bays and cargo handling areas have been designed to accommodate 12.2m (40ft) trailers. To alter these to accept the relatively few larger units which might appear would be totally uneconomic.
The move will almost certainly be for an extra trailer axle. On the question of size it looks as if there will be no really noticeable difference to the layman. The image of even higher, wider vehicles is an even wilder fantasy of the anti-lorry brigade.
The environmentalist arguments that heavier commercial vehicles will lead to greater damage to both roads and buildings have no real evidence to prove either point. Studies by the Government Transport and Road Research Laboratory have failed to prove that heavier weight vehicles have any greater effect than lighter vehicles.
To quote the Laboratory's Report no. 582 by D. R. Leonard, J. W. Grainger and R. Eyre: "No clearly defined relationship was observed between gross vehicle weight and dynamic loading or vibration.
"A true assessment of the effect of weights alone was generally not possible as other parameters also changed , for each vehicle a comparison of the two vehicles F & G (eight vehicles were used in the tests) with similar suspensions and axle spacing, showed that the heavier vehicle generated slightly higher loads and vibrations.
"Unfortunately, this is insufficient evidence for a generalisation to be made."
In fact the report went on to say that the most important influence on loading and vibra
tion are the dynamic properties of the vehicle suspension system. Finally, the report stated: "The experimental results have shown that 38-ton and even 40-ton vehicles need cause no greater dynamic loads or vibrations than some existing 32-ton vehicles."
The advantages
If 40-tonne vehicles are to be used, what then are their advantages? One 40-tonne vehicle or three -16-tonne vehicles will carry a similar payload of 28 tons. The larger vehicle has a gross weight of 10 tons less then the three 16-tonners, and would use two thirds of the fuel and would occupy only one litre of their road space.
For those who complain about trucks occupying too much of the road already, the latter point is probably the most important.
There are massive benefits to the community as a whole. Goods may not become much cheaper, that would be a wild claim, but prices could be stabilised.
Precious fuel oil would be conserved by using the larger vehicles, and fewer drivers would need to be employed. It is accepted that this would * cause other ills for which all cures would be sought. Additionally the weight burden on the roads by using one 40-tonner instead of three 16-tonners would also be reduced.
Finally, although hauliers, would not welcome an increase in road tax by whatever means it is collected, I've no doubt they, would like to see their money used for the purpose for which it was intended — building and maintaining the roads.
Operators do not want to drive through the main streets or small villages or large towns. It is hard work and time consuming lugging an artic through narrow twisting lanes of traffic, and to transport men as with all businesses time is money.
If more by-passes and motorways are built to accommodate the vehicles and take them away from towns and villages everyone will benefit. The operators' costs will stabilise, price rises will be less steep and the environment in which we all live will be protected.