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Structural Practices ACCESS ROAD (Urban) Urban access roads are needed to provide access from a township, county, or state highway to a development, or to provide travelways within the planned area. Roads should be located to serve the purpose intended, to facilitate the control and disposal of water, to utilize topographic features, and to include scenic vistas where adaptable. The recommended minimum width ofthe roadbed is 14 feet for one-way traffic and 20 feet for two-way traffic. The two-way traffic width shall be increased approxi- mately 4 feet for trailer traffic. The recommended minimum tread width is 10 feet for one-way traffic and 15 feet for two-way traffic. The tread width for two-way traffic shall be increased ap- proximately 5 feet for trailer traffic. The recommended minimum shoulder width is 2 feet on each side of the tread width. Erosion Control Measures Needed erosion control measures should be provided for road ditches, cut slopes, fill slopes, and cross drains. This will usually require a combination of struc- tures and vegetative cover. All cuts and fills should have side slopes that are stable for the soil or soil material involved, and flat enough so that they can be vegetated and maintained with adapta- ble equipment. In some cases, slopes may need to be gravelled or riprapped. Culverts, bridges, or grade dips should be provided at all natural drainageways. Design of these structures must be in keeping with sound engineering principles for the class of vehicle or equipment used on the road. Roadside ditches must be adequate to provide surface drainage for the roadway and deep enough, as needed, to serve as outlets for subsurface drainage. Surfacing Access roads must be given a wearing course or surface treatment when required by traffic needs, climate, ero- sion control, or dust control. The type of treatment will depend on local conditions, available materials, and the existing road base. Where these factors or the volume of traffic are not a problem, no special treatment of the surface is required. Sound engineering principles shall be followed to insure that the road will meet the re- Land grading should be done in such a way to prevent erosion. quirements of its intended use and maintenance re- quirements will be in line with operating budgets. Traffic safety is a prime factor in selecting the angle of intersection with public highways. Preferably the angle should be not less than 85 degrees and the clear sight distance to each side shall be not less than 300 feet where site conditions permit. Construction Construction operations shall be carried out in such a manner that erosion and air and water pollution will be minimized and held within legal limitations. The com- pleted job shall present a workmanlike finish. Consid- eration will be given to the following: 1. Removal and disposal of trees, stumps, roots, brush, weeds, and other objectionable material from the work area. 2. Removal of unsuitable material from the roadbed area and replacement with approved material. 3. Grading, subgrade preparation, and compaction re- quirements. After the roadbed is graded to the re- quired elevation for the subgrade, that portion of the roadbed in which subgrade is to be prepared shall be loosened to a depth of 6 inches and all stones, roots and other objectionable material removed and dis- posed of. No subgrade shall then be compacted to the required density. 4. Surfacing requirements. Placement of the surface course shall be in accordance with sound highway construction practice for the surface material used. 5. Aesthetics. 6. Vegetation of all exposed earthen surfaces with adapted species. 40