Blackout-Readyby Crisis-Ready Society

Home / The guide / Land and site

Land and site · Master site plan and civil design · site-13

Design the access road and driveway

Plan an all-weather driveway that fire engines, delivery trucks and well drilling rigs can use. Grade, width, turnarounds and drainage matter more than surface finish.

How

  1. Get your local fire access rules. Example (Oregon adoption of IFC Appendix D): fire apparatus roads at most 10% grade, 20 ft wide for dead ends up to 500 ft, a turnaround for dead ends over 150 ft (such as a 120 ft hammerhead or 96 ft diameter cul-de-sac), and able to carry 60,000 lb.
  2. Example (Sedona, Arizona residential guide): a 12 ft driving surface for one- and two-family dwellings, 13 ft 6 in vertical clearance, and in wildland areas 10 by 30 ft turnouts on narrow driveways over 200 ft.
  3. Check grades with the slope calculator in this module. Follow contours to keep grades gentle and avoid long straight runs down the fall line.
  4. Keep the road out of drainage lines, and plan how water will leave the surface: crown or cross slope, roadside ditches and culverts at low points.
  5. Give the surface a 3 to 5% cross slope (outsloped, insloped or crowned) and add rolling dips or culvert cross drains. USDA Forest Service maximum spacings: on 0 to 3% grades about 120 m (non-erosive soil) or 75 m (erosive soil); on 7 to 9% grades 75 m or 40 m; above 12% grades 50 m or 30 m. Fine silts and fine sands count as erosive.
  6. Size culverts for a design storm; US Forest Service guidance recommends a 20 to 50 year storm for culverts on low-volume roads, with extra capacity where flows are uncertain.
  7. Plan vegetation clearance beside the road (PNNL guidance: trim branches 10 ft back from each side) and visible house numbers.
  8. Ask your local road authority about the connection to the public road; it may need a permit.

Do these first

Sources

  1. Defensible Space: Protection Against Wildfires. Pacific Northwest National Laboratory, Building America Solution Center (US DOE), accessed 2026-11
  2. Low-Volume Roads Engineering Best Management Practices, Chapter 5: Hydrologic Analysis. USDA Forest Service, accessed 2026-11
  3. Oregon Fire Code Appendix D: Fire Apparatus Access Roads. Linn County, Oregon, accessed 2026-11
  4. Residential Access Guide. Sedona Fire District, Arizona, accessed 2026-11
  5. Low-Volume Roads Engineering Best Management Practices, Chapter 7: Drainage of Low-Volume Roads. USDA Forest Service, accessed 2026-11

Open in the interactive guide