Like studies by Coverdale & Colpitts, made at the same time on the other main routes approaching Baltimore, showed a similar distribution of the entering traffic.
The conditions which these examples describe are not peculiar to Baltimore and Washington. They are typical of the conditions that exist at all large cities. On all main highways approaching such cities, a very large proportion of the traffic will be found upon investigation to have originated in or to be bound to the city as its ultimate or inter mediate objective.
In general, the larger the city the larger is the proportion of the traffic on the main approach highways that is thus essentially concerned with the city.
As evidence supporting this generalization, reference is made to table 14 and figure 29 which record the results of origin-destination studies made at 27 cities of various population classes, from 6 of less than 2,500 persons to one of a population between 500,000 and
