Page:John Nolen--New ideals in the planning of cities.djvu/55

CITIES, TOWNS AND VILLAGES A graceful curve or a well-planned fork will tend to break the monotony of endlessly long, straight streets. In the planning of main thoroughfares, topographical conditions should not be permitted to exercise an undue influence. Detours which would materially lengthen the route should be made only to avoid excessive grades. Heavy cutting and filling is to be preferred to many windings in a great traffic route which may be required to carry the trade of a large city for centuries. The first plan for such a thoroughfare must usually be considered its permanent one, for it is seldom, and then only at great cost, that its capacity can be increased after the abutting property has been built up. Among the fundamental principles in the planning of main thoroughfares which are generally accepted as sound, are the following:

1. That some central city authority should undertake the planning of all main lines of communication,

2. That arterial streets and roads should be taken seriously as highways for intercommunication, and enough direct routes preserved from being blocked to provide for considerable future increase of road traffic.

3. That we should recognize that streets now carry've hicles of at least three distinct speeds, and that wherever possible, efficiency requires separate lines and tracks for the useV of each.

4. That the danger and delay caused by the crossing of main thoroughfares should be reduced, so far as possible, by gathering up the minor roads into secondary streets, and by bringing the latter into main thoroughfares only at fairly long intervals.

5. That where these junctions occur, ample space for the circulation and distribution of traffic should be provided to facilitate passing and crossing and to make it safer.

6. That the location of main thoroughfares should not be