shown by the figures appearing at the end of the tentacles running to the respective States. The sum of the numbers of cars bound to or from points in States bordering on or near the Atlantic coast is 300. This figure represents substantially the total volume of average daily passenger-car traffic moving over all main-traveled highways between the east and west coasts. By a similar reckoning the average daily passenger-car traffic between the west-coast States and all points east of the Mississippi River over all main east-west highways will be found to be less than 800 vehicles. These vehicles could not be attracted to a single east-west route under any circumstances.
Plate 2 shows by a similar diagram the origins and destinations of motortrucks and busses observed at the same Idaho, Nevada, and Arizona points and indicates that the range of travel by such vehicles is much shorter than the passenger-car range represented in plate 1.
Similarly plates 3 and 4 show the origins and destinations of all passenger automobiles and motortrucks, respectively (other than vehicles of Florida registration), passing on an average day over the Florida State line. The traffic data represented are the results of counts made throughout the year 1937 on all main highways crossing the State line. Plate 3 shows that there is a well-developed movement between Florida and the Middle Atlantic and New England States that might conceivably be accumulated on one properly located free highway between the Potomac River and the Florida line. It shows also that there is another well-developed movement that might be accumulated on a single properly located free highway between Chicago and Florida.
It may be observed that the number of passenger cars of other than Florida registration shown, in plate 3, as bound to or from the three Pacific Coast States is 23. Cars of Florida registration, not included in the graphed totals, similarly bound to or from the three West Coast States add an average of 3 daily to this number, making a total of 26, as counted at the Florida line. It is interesting to compare this total with the 20 cars shown in plate 1 as having been found in Idaho, Nevada, and Arizona to be bound to or from Florida points. The close agreement of these figures, resulting from counts made independently at points separated by almost the width of the continent, is indicative of the high accuracy of the highway planning surveys.
HIGHWAY TRIPS ARE PREDOMINANTLY SHORT
Plate 5, based upon planning survey data from 11 representative States, shows the range in frequency distribution of the lengths of all one-way trips of passenger cars extending beyond the limits of cities. The States represented are Florida, Kansas, Louisiana, Minnesota, New Hampshire, Pennsylvania, South Dakota, Utah, Vermont, Washington, and Wisconsin. For each range of trip length, represented horizontally in miles, the graph shows by the height of the vertical bar to the bottom of the shaded areas the lowest percentage in which trips of that length are found in any of the 11 States. To the top of the shaded area the height of the bar for each range of trip length represents the highest percentage in which trips of that length were found in any of the 11 States. The vertical length of the shaded bands, represents to the percentage scale at the left the range between the maximum and minimum percentage in which trips of each range of length were found in the 11 States.
