The data represented in plate 5 and table 1 have a double significance in relation to the estimation of potential traffic for the proposed highways with limited access.
1. They indicate that a considerable proportion of an existing traffic moving directly along the line of the proposed facility cannot be counted upon to use the facility unless the distances between access points are very short. Any given distance between access points must be considered as excluding from potential use of the facility all or practically all of the traffic found to be desirous of moving directly along the line of the facility for distances shorter than the access spacing.
2. The data also indicate that, as a rule, the amount of traffic that would be attracted by any of the proposed limited-access highways from other generally parallel routes will vary inversely with the distance separating the new highway from the parallel routes. Generally it must be assumed that for most of the traffic moving on a parallel route, diversion to the proposed highway would involve some indirection. The amount of such indirection that would overbalance other attractions of the new highway would vary with the length of the trip possible along the new highway before diverging to destination. As long trips are shown by plate 5 and table 1 to be a small percentage of all trips, and as only a traveler embarked upon a fairly long trip would accept any considerable lateral diversion from his direct course in order to enjoy superior highway facilities, it follows that the amount of traffic that can be counted as transferable to a limited-access highway from a generally parallel normal highway at a considerable distance must be quite small.
As indicated by table 1, residents of large cities, on the average, make longer trips than residents of small cities. Evidence that will be submitted hereafter (see pl. 8) shows that as a city is approached, the volume of traffic begins to increase at a greater distance from large cities than from small ones, which corroborates the stated rule. As New York is our largest city, the traffic diagram presented in plate 6 may be considered to represent the extreme condition in respect to average length of trip and ratio of numbers of long to short trips. Yet, even at New York, as plate 6 shows, an average daily traffic of 82,166 crossing the Hudson River by all facilities between the Battery and Tarrytown dwindles to less than a fifth of that amount within 20 miles. This dwindling occurs despite the existence of a ring of satellite cities which, by their local influence tend to keep the volume up.
It is of particular interest to note in plate 6 that only 3,100 of the 82,166 vehicles crossing the Hudson River are bound from or to points in States west and south more distant than New York, Pennsylvania, and New Jersey.
MAJORITY OF AUTOMOBILE OWNERS HAVE LOW INCOMES
A survey recently made by the Bureau of Foreign and Domestic Commerce, United States Department of Commerce, shows that the majority of family passenger cars are owned by families of very moderate income. As indicated in the table below more than half of all family cars are owned by families that have an annual income of $1,500 or less. Less than 5 percent of all family cars are owned by families that have an annual income of more than $5,000. Less
