LIMITING ACCESS TO THE INTERREGIONAL ROUTES
The character of the interregional routes as main collectors of through traffic justifies the granting of preferential right-of-way to traffic moving on them over all crossing and entering traffic everywhere, throughout the system. A proper facilitation of the express traffic with due regard for safety and economy requires, moreover, a reduction of the number of access and crossing points to a practicable minimum. This, in the opinion of the Committee, makes it desirable, as promptly as possible, to provide for the legal designation of all routes of the recommended system, in both their urban and rural sections, as limited-access highways. This designation will empower administrative authorities, wherever and whenever necessary for the convenience of express traffic and the promotion of safety, to deny access to the interregional highways from abutting lands or control or limit such access as may be found desirable, and similarly to deny or limit access, as desirable, from other public roads.
Principles of Location and Design for Limitation of Access
The proposal to confer this essential power does not suggest that it be inflexibly or arbitrarily used. To deny access to the routes from all abutting properties will not be necessary invariably. On the more lightly traveled rural sections in sparsely settled areas, it may be reasonable to permit access from substantially all properties. But in any case the place and manner of access should be so defined and controlled as to preserve the character of the express route and, as completely as practicable, to prevent the occurrence of collisions.
In many cases it will be found that unimportant rural cross roads can be closed and their slight traffic directed to other points of crossing. And where, in rural areas, the traffic on the interregional highway is light or only moderately heavy, it may not be necessary, immediately at least, to go to the length of grade separation at all retained intersections But where a grade crossing permitted on the inter regional highway, the design of the intersection and its signing should enable and require operators of crossing vehicles to make a positive determination of the safety of crossing, and should reveal to operators of vehicles on the main highway the presence of vehicles about to cross or enter. All traffic should be required to halt before crossing the main highway at grade, but in no case will the simple posting of stop signs on crossing or entering roads be sufficient. The design of the intersection should additionally provide all physical safeguards, such as definite traffic channels and refuge islands, decelerating and accelerating space, etc., as may be necessary to afford a maximum of safety for both of the intersecting traffic streams and a maximum of facility for the traffic on the interregional highway. A suggestion of what this may mean at a crossing on a section of the system carrying moderately heavy traffic is shown in plate VII.
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