ROAD WIDTH LIMITS HIGHWAY TRAFFIC
ROAD WIDTH LIMITS HIGHWAY TRAFFIC
George C. Diehl
The New York Times
February 16, 1919
Engineers Preparing for New Construction Era to Meet Increasing Motor Truck Demands
BUILT FOR EFFICIENT SERVICE|
New 3½-ton Republic truck model especially constructed for heavy highway transportation. Wheelbase 165 inches.
By George C. Diehl, Chairman Good Roads Committee, American Automobile Association.
Never was intelligent study of highway problems more necessary or has there ever been greater need of public support of a comprehensive road building program. Transportation is one of the greatest reconstruction problems and highway transportation is its most acute phase. That cost of highway improvement, construction, and maintenance bears a definite relation to the amount of tonnage carried is apparent. Ultimately the justification of any road building program must rest on a saving in the cost per ton mile.
The passenger automobile gave the first general indication of the advisability of better roads, but the rapidly increasing use of motor trucks is emphasizing as never before the necessity of wider, more durable and safer roads, and also the impossibility of proceeding further without a sound fiscal policy.
New York State authorized in 1905 and 1912 two $50,000,000 bond issues for road purposes. Seven or eight thousand miles of roads have been improved and a few years ago it was generally believed that the end of the construction period was in sight and that in the future the problem would be principally one of maintenance. So widespread was this opinion among road enthusiasts that a suggestion of future bond issues would have been ridiculed.
The effect last Winter of the motor truck convoys on certain parts of the main improved road across the State was a real awakening to many who had studied road building superficially. It was admitted without argument that a more durable and expensive construction was required.
It was also recognized that the rapidly increasing tonnage of freight carried over highways would entail increased expenditures per mile, and it seems not only probable but certain that the tonnage would so increase that the two previous bond issues would prove inadequate, and could not keep pace with the ever-increasing demands. These facts were accentuated by the increasing cost of building materials and by difficulties in the labor market.
There are a few who still believe, or rather hope, that a decrease in road costs and easier labor conditions may put the problem back to the old stage, and that with Federal funds and with slightly increased local support the original program of a connected and well-developed State system of highways could be finished without radical change in style of construction and without greatly augmented State road funds. Owing to the many diverse questions that enter into a thorough consideration of road building, it is difficult to briefly state the matter even generally.
That highways have a definite carrying capacity will at once be conceded—that this capacity is dependent upon the width of roadway, weight and speed of motor vehicles is certain. Formerly great objection was made even to moderate speeds. Now, in considering speed as an economic problem, it cannot be denied that, other conditions be unchanged, a motor vehicle operated at an average speed of fifteen miles per hour will carry 50 per cent. more tonnage than at a speed of ten miles an hour, and likewise if the average speed is increased to twenty miles then the capacity of the highway will be doubled. Similarly three-ton trucks will increase highway capacity 50 per cent. over two-ton trucks. Five-ton trucks will make an increase of 150 per cent., and six-ton trucks will triple the amount that can be carried.
If there were twenty-five trucks to the mile they would be only 200 feet apart, and that is probably as near together as they could be spaced on the average to maintain even the lower speeds. A sixteen-foot improved surface is generally known as a double or two-track road, and fifty vehicles, that is, twenty-five operating in each direction, would completely fill such a road. This number, it is believed, will not be unusual in the comparatively near future on a number of cross State roads. Of course, assuming that these are all motor trucks, it is not difficult to definitely say that any extensive passenger motor business must travel on another road, unless the policy is adopted of building four-track roads, and it will be equally impossible to carry the future freight and passenger business on a two-track highway as it would for the New York Central Railroad to move its traffic over a two-track railroad.
Greater weights and faster speeds will on many highways obviate, for a long time at least, the necessity of extensive widening, and even this remedy would not be required on many highways in the less populated sections of the State or in locations where parallel roads have been constructed.
The main highway from Buffalo to New York is about 450 miles long. To widen with the most durable construction this important thoroughfare to twenty-four feet in open country and thirty feet near the thickly populated sections would cost at least $10,000,000, and probably a great deal in excess of that figure, which does not include much necessary rebuilding, and does not take into account the widening and strengthening of bridges and the separation of grades at railroad crossings.
It can be safely stated that an enormous extension and revising of present plans can only be accomplished after it has been positively demonstrated that the entire cost is more than offset by the saving in the cost of transportation. If 2,000 tons were transported daily over a mile of highway and an improvement would save 5 cents per ton, then there would be a daily saving of $100 on an annual amount of $35,000, which, if spread over a period of five years, would justify a large expenditure. Such statistics can be gathered by the Highway Department while the amount remaining in the existing bond issue is being expended.
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