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Show MOTOR TRUCK ROAD AYEAR There is a special field of transportation trans-portation in which the motor truck is the only logical means of conveyance. convey-ance. How large a field it .is, is shown by the fact that 300,000,000 tons of material ere shipped by the truck in 1919. Suppose this freight were transported in one-ton trucks. It would mean that 900,000,000 tons of traffic (including weight of vehicles vehi-cles and cargo) would pass over the roads of the country. If transported in 7 1-2 ton trucks the roads would have to bear only 600,000,000 tons of traffic. This is because the average aver-age one-ton truck carries two tons of vehicle weight, while in 7 1-2 ton truck, this ratio is reduced to less tha,n one ton of vehicle weight for each ton of freight capacity. Regardless Regard-less of what form restrictive legislation legisla-tion may take the total amount of ma terial shipped in motor trucks in the, year 1920 will obviously be greater than the total of 1919. This country is suffering from various kinds of shorta.ges but they are almost all directly the result of inadequate ' transportation. Since no other transportation trans-portation agency can now take the place of the motor truck in its own recognized sphere, it is obvious that pvprv hpQW Hnttr tT-nlr f - i tv , the roads will be replaced by several smaller ones. The result will be increased in-creased road wear and ii creased cost transportation. As practically all the products of the farm and factory make some part of their journey from producer to consumer in motor trucks, it is necessary to make sure there is no other alternative before framing legislation which will increase in-crease motor transportation costs. There are many fields of short dis-trnce dis-trnce light delivery in which the 11 ghter truck is better adapted. However, How-ever, when bulk hauling is considered, consider-ed, the light truck's greatest asset in comparison with its big brother is its speed. For a two-ton truck to transport material as economically as a heavy duty model it would be necessary nec-essary for it to travel as three times the speed of the larger - truck. Of course the light truck cannot do this but it does travel at considerable higher normal speed. Its increased speed, however, produces road wear in excess of that caused by the heavy truck in spite of the fact that the latter lat-ter is accomplishing far more. It has been definitely proved that increased speed causes more rapid road wear than increased weight. It is not necessary nec-essary that the heavy duty truck resort re-sort to destructive road speeds in order or-der to furnish economical transportation. transpor-tation. Tire width bears an equally impor ant relation to comparitive road wear A steam roller for example is about the heaviest vehicle which passes over ov-er a highway, yet because of its broad road bearing surface its effect on the roadway is beneficial rather than harmful. Likewise weight in a motor mot-or truck is destructive only when not accompanied, by a sufficient width wid-th of tire. The fact is well established establish-ed that a load of 800 pounds per in. of tire surface is not damaging to an ordinary roadway and the heavy duty du-ty truck is always built to1 conform to this requirement. A 7 1-2 ton truck has1 one inch of tire width for each 666 pounds of weight. If restrictive motor truck legislation legis-lation is necessary and it undoubtedly undoubted-ly is, why not proceed, on a basis which epnalizes actual road wear, 'olui l ii ti ii uiic rviiiv-u ircuauz,ea ulii- ity and determine by actual test and I far reaching analysis just where the blame for excessive road wear belongs? be-longs? Then, and only then will the judgment be a permanent benefit to the growth of highway transportation transporta-tion and its relation to public welfare. wel-fare. Scientific American. |
