One of the most important considerations in highway design is the temporary highway detour and/or shoofly. See Section E 542 Preliminary Design Considerations. Detour considerations may affect the final alignment and grade of the intersection. It may also influence the underpass-versus-overpass decision, the use of walls or side slopes, the amount of right of way necessary, and the design and construction costs. As may be seen, temporary bypasses may represent a large percentage of the total project cost, and its design aspects should be thoroughly examined.
E 545.1 Design Criteria (Temporary Detours)
The temporary highway detour should follow the identical design standards that are required of the major highway. Deviations should be considered only in the case of extenuating or critical circumstances or situations involving excessive costs. Two of these deviations are as follows:
- Temporary pavement should be a minimum of 4 inches of asphalt concrete. An additional 4-inch minimum of select material base may be necessary.
- Temporary sidewalks may be a minimum of 3-inch-thick asphalt concrete.
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