Elements Governing the Development of Highway Traffic

The purpose of this paper is to discuss the amount of future traffic upon American highways and to compare this with the traffic capacity of a two-lane road.

In order to do this, it is necessary to project what the progress is to be in the future, and this is always fraught with many uncertainties. Even if the physical facts on which to base a prediction are known, social forces may not continue to act as in the past, and thus new conditions arise that affect vitally the results. If the facts are known, and the forces, both social and economic, do not sensibly change, then one may predict with considerable assurance what the future may be expected to bring forth.

The physical facts upon which highway traffic rests are the number of vehicles using the road in a given time, the road mileage made by these vehicles during some definite period, and the mileage of the system of highways upon which the traffic moves. If, through a considerable period of time, these quantities have persisted at concordant rates, then future values may be predicted. In the instance of highway use, the values thus found will be approximately true, provided the causes that create a desire for the use of the motor vehicle do not change. For the present purpose, it is assumed that such will be the case; that people will not tire of the motor vehicle as a form of recreation; that, due to further congestion, increased traffic will not become the means that will strangle itself. All that is favorable to the continuance of travel by highway is to be assumed. With these conditions imposed, it is useful to endeavor to see what the future holds in store for the highways.