Page:Interregional Highways.pdf/123

Rh Other than the sections mentioned, there are few if any of the more heavily traveled existing highways approximating in location the routes of the interregional system, that approach in their present state the standards proposed for the system. On most of these non-conforming heavily traveled roads, there is present need for major improvement which would generally be associated with those features of design essential for the provision of free traffic flow and only to a lesser degree with the structural quality and condition of pavements.

Among the more lightly traveled of existing highways approximating the location of sections of the system, substantial conformity to the less exacting standards Proposed for such sections of the system is more common. But of these more lightly traveled highways, even, a large mileage cannot be regarded as an acceptable addition to the system without major improvement—improvement which again involves the provision of features of free traffic flow to a greater extent than the provision of adequate road surfaces.

CONDITION OF ROADS

Surfaces or pavements.—Regarding the condition of the existing rural roads, the nearest approach in any particular to the recommended standard of adequacy is reached in the character of the surfaces or pavements, as shown in table 16 which records the type of surface improvement existing in 1942 in relation to traffic densities. Of the rural roads included only 99 miles were unsurfaced. Untreated gravel and stone surfaces existed on only 168 miles or 0.6 percent of the total rural] mileage. All other sections of the rural roads included were improved with some form of dustless surface or pavement, ranging from bituminous surface-treated gravel or stone surfaces to the highest types of pavement.

Bituminous-treated surfaces existed on 2,074 miles or 7.0 percent of the total rural mileage, mixed bituminous surfaces on 8,247 miles or 28.0 percent of the total mileage, and bituminous penetration surfaces on 1,772 miles or 6.0 percent of the total mileage. Lengths