Wagoner County weighs flexible road standards for rural subdivisions

Wagoner County commissioners on Oct. 14 moved to send a draft amendment to the subdivision regulations to the planning commission that would let the county consider alternative pavement sections for lower-density, open-ditch subdivisions instead of applying a single structural-number standard across the county.

County planning and zoning official Casey Sanders told commissioners that current code sets a structural number of 3.9 and other uniform requirements (a 20-year minimum design life, a 10-trip-per-lot ADT assumption and a 5 percent truck assumption) that apply to every subdivision. Olson Engineering prepared a site-specific design for The Pines subdivision that uses a lower structural number (about 3.1) and different pavement-layer recommendations. Developer-hired and county-hired engineers disagreed about whether the county should keep a single minimum structural number or allow engineering flexibility.

The difference matters because the structural number drives pavement thickness and therefore construction cost. Marco Celestri of Building & Earth, the developer's pavement engineer, told the board that the…