Home >> A-treatise-on-roads-and-pavements-1903 >> Sheet Asphalt to Work Of Maintenance Gravel >> Width of Wheelway

Width of Wheelway

cross, ditches, feet and section

WIDTH OF WHEELWAY. The width of the right of way varies greatly, but is usually between 40 and 66 feet (see § 88). With a 66-foot right of way it is customary to reserve about 6 feet outside of the ditch on each side for a foot-way, and grade up the remaining 54 feet. With a 40-foot right of way it is customary to reserve 6 feet on each side for foot-ways, thus leaving 28 feet for ditches and wheel-ways. For equally good surface drainage, the greater width requires deeper ditches and more cost in con struction, but permits a wider distribution of the travel when the roads are muddy or rough. The deep ditches are harder to main tain, and as a rule• the native soil from the bottom of deep ditches is not so good for road building purposes as that nearer the surface. The cost of maintaining the road depends upon the amount of traffic, and is practically independent of the width. Therefore the width to be improved depends chiefly upon the width of the right of way, the character of the soil, and the climate. In a wet climate, with soil easily working into mud, a wide wheel-way is desirable; while in a dry climate, or with a soil not readily forming mud, a nar row wheel-way is preferable.

Cross Section.

The cross section or transverse contour of a road is an important matter with reference to the cost of con struction and of maintenance. The cost of construction is chiefly

dependent upon the form of the side ditch and has already been considered in § 110. The cost of maintenance depends upon the amount of crown of the surface, which has been discussed in § 114. Figs. 9 and 10, page 85, show two forms of cross section. The former has the smaller side ditch and a curved crown; the latter has a larger side ditch and an upper surface composed of two planes meeting at the center. Both may be constructed with the ordi nary scraping grader (§ 142), and in both cases the side ditches furnish sufficient earth to make the crown.

Fig. 12 shows a form of cross section sometimes adopted for earth roads an villages and towns. The gutter is usually made next to the sidewalk, which is objectionable, since horses must stand in the mud and water when hitched in front of the property. The form shown in Fig. 12 is free from this objection. A narrow berm is left between the sidewalk and the edge of the slope to prevent crowding the gutter too close to the shade trees, which are usually planted just outside of the sidewalk. The gutter shown in Fig. 12 decreases the available wheel-way, and consequently in some locali ties would be undesirable. This cross section also can be made and maintained with the ordinary scraping grader.