to recommend standards for the Interstate System by June 1945, and these were adopted by AASHO and approved by the Federal Works Administrator in August 1945.[N 1]
Of necessity, the Interstate standards were a compromise. A few States thought they were inadequate, pointing to the provision permitting three-lane highways for traffic volumes intermediate between those requiring a two-lane highway and those requiring a four-lane divided highway. Some criticized the weak provisions permitting grade crossings with railroads and other highways for low-traffic sections of the Interstate System. In these respects, the standards fell far below those for existing parkways and turnpikes which had been held up to the public by many people as the ideal for the Interstate System.
To get wide acceptance of the standards, the Committee equivocated on other elements of design by setting up “minimum” and “desirable” levels of de- sign. Thus, for level country, a State could elect to use either a 60- or 70-mile per hour design speed. For right-of-way, the “desirable” width for divided highways was 250 feet, but in a pinch the State could get by with the “minimum” of 150 feet.
- ↑ When the 1956 Federal-Aid Highway Act specifically called for adoption of uniform design standards for the Interstate System, these earlier standards were the basis for the new standards, permitting completion of the work in 2 to 3 months.
The lack of access control prevented free-flowing movement on this four-lane, undivided bypass of U.S. 101 in California.
Control of Access Recommended but Not Required for Interstate System
The most important deficiency in the standards concerned a matter over which AASHO had no control and little influence with the States. This was the control of access to the highway from abutting property. Two decades of experience had shown that new highways invariably attracted ribbon development by commercial enterprises catering to the traffic on the highway. Movements to and from these businesses disrupted the traffic stream on the highway and greatly increased accidents. Eventually, the ability of the highway to carry traffic was reduced far below its original capacity by the roadside activity. At the same time the cost of future widening was made prohibitive. Gradually, highway administrators began to realize that the only way to protect the capacity of the highway was to deny or restrict access to the road from the adjacent private property. This growing realization ran counter to the most deeply ingrained
