Page:Interregional Highways.pdf/116

90 increase the effectiveness of maintenance processes and lower the cost of adequate upkeep.

Without sacrifice of distance or economy it will often be possible to bring the highway into view of a lake or river, an interesting rock formation or wooded hill. At no greater expense one location will provide frequent opportunities for distant vistas of natural charm that are unobtainable in an alternate location. For such enduring investments as the interregional routes there should be no sparing of whatever thought and care may be necessary to place these roads in locations of utmost fitness from every point of view, and this includes the fullest practicable development of scenic possibilities, consistent with the primary requirements of traffic service.

In the acquisition of right-of-way, thought should be given not only to the width required for the physical highway facility, but also to that required for protection against encroachment and protection and enhancement of the view from the highway.

The former will involve the creation of a space barrier Between the highway and roadside activity of any character whatever—space in which to screen from view disturbing or objectionable activity and space in which to control access to gasoline stations, restaurants, wayside stops, and other similar service facilities of an essential character.

The latter will involve the obtainment of space in which to screen the view of signboards and objectionable and unsightly objects, to blend the road verge into the natural landscape, to frame pleasing vistas, and to accommodate historical markers, overlooks and other halting and resting places in attractive surroundings.

The planning of clearing operations should provide for the conservation of desirable existing vegetation and trees and the saving of topsoil to the greatest practicable extent; and the grading should provide the flattened lateral slopes and rounded contours that are necessary to mold the highway into its natural surroundings.

On two-lane sections, the width of roadway and shoulders will be determined by traffic considerations, and the necessity of long sight distance to permit maximum facility of passing will limit the use of curvature for landscape effect. On such sections an ample right-of-way, variously and appropriately treated, can do much to relieve the monotony of driving over long, smooth stretches of straight highway, and will contribute largely to the safety as well as the pleasure of travel. Under these conditions the value of land is likely to be relatively low and the need of a reserve of space for future road widening will supplement the requirements of appropriate landscape treatment in support of the economy of a present liberal acquisition of right-of-way.

On divided, four-lane sections in rural areas, variation of the width of the median strip, a permissible more liberal use of curvature, and separate adjustment of the grades of the divided roadways to the natural slopes of the terrain will add interest to the landscape treatment and often reduce the cost of construction. Where the location lies on the side of a hill or a gentle cross slope, for example, construction cost will usually be substantially lowered by building the separate roadways at different levels, and travelers on both roadways will have an unobstructed view of the countryside (see plate VII). A similar divergence in the alinement of the two roadways to take advantage of natural topographic conditions, such as location on the