Page:America's Highways 1776–1976.djvu/141

 A roadside park in Connecticut, 1958.

Landscaping and erosion control were not the only reasons for adopting wider rights-of-way. By the mid-1920’s, the main roads near and between large cities were getting seriously congested. The easiest way to relieve this congestion was to add another lane, and several State highway departments did this extensively, despite a growing realization that three-lane roads might increase the possibility of head-on collisions. By the middle thirties, three-lane roads were practically obsolete, but hundreds of miles of highways had been widened to four lanes, especially in Cook County, Illinois, and Wayne County, Michigan.

However, these too proved to be dangerous, and many highway administrators began to believe that the only safe way to build multilane highways was to completely separate the opposing lanes of traffic, as had been done for years on city boulevards. In 1929, Milwaukee County, Wisconsin, rebuilt a part of the Blue Mound Road as a “split-slab highway” with “neutral ground” between the opposing lanes of traffic, leaving the remainder with an undivided four-lane pavement. After this road was opened to traffic, the commissioners were pleasantly surprised to observe that the divided part of this highway was able to carry more traffic at 10 to 20 miles per hour greater speed than the undivided part.

Despite their superior safety characteristics, acceptance of divided or “dual” highways was slow, and by 1937 there were only 1,200 miles of nonurban divided highway in the United States.

In that year, Chief MacDonald reported:

The large volumes of traffic that now flow between densely populated localities have created a demand for wide, multiple-lane highways, built according to the highest standards of grade and alinement, with opposing traffic separated by a center parkway, bypassing all cities, with structures separating streams of traffic at all highway and rail crossings, and with access from side roads permitted only at carefully selected points. Such highways offer great savings in time and in vehicle-operating costs to commercial vehicles, and to the drivers of private vehicles they offer freedom from dangers of the highway and from other vehicles as nearly complete as it is possible to attain.

That large volumes of traffic would flow constantly over such highways between densely populated localities there is no doubt—a traffic large enough to justify the high cost of such improvement with reasonable assumptions as to the value of the savings in fuel and time and those resulting from greater safety and freedom of travel. However it is not readily apparent how any large mileage of such highways might be financed.

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