A stabilized construction entrance (or construction exit) is a stabilized pad where vehicles leave the site, designed to knock mud off tires before they reach a paved road. Tracked-out sediment on streets washes into storm drains with the next rain.
What the EPA Construction General Permit requires
Under EPA's 2022 CGP, operators must minimize sediment track-out:
- Restrict vehicles to properly designated exit points.
- Use appropriate stabilization at all points that exit onto paved roads (the permit's examples are aggregate stone over geotextile or non-woven filter fabric, and turf mats).
- Add track-out controls as necessary so sediment is removed before vehicles exit.
- Where sediment is tracked onto paved roads, sidewalks or other paved areas, remove it by the end of the same business day, or by the end of the next business day if it occurs on a non-business day, by sweeping, shoveling or vacuuming.
- Don't hose or sweep tracked-out sediment into storm drains, drainage features or waters.
Typical specifications
State and local BMP manuals set exact specs. Common practice includes:
| Item | Typical practice |
|---|---|
| Stone | Clean, coarse crushed aggregate (often 2 to 3 inches, or per the state's gradation) |
| Thickness | Several inches deep (commonly at least 6 inches) |
| Length | Long enough for several tire rotations on the stone (often 50 feet or more) |
| Width | Full width of the exit, wide enough for the largest vehicles |
| Geotextile | Under the stone to keep it from sinking into the subgrade |
| Drainage | Runoff from the pad directed to a sediment control, not the street |
Extra track-out controls
- Rumble strips and rattle plates: steel grates that shake mud loose (both named as examples in the CGP).
- Wheel washing (also a CGP example): with the wash water routed to a sediment trap or basin, never to the street.
- Construction mats: reusable mats for short-term or tight exits.
- Street sweeping: scheduled and on-call, especially in wet weather.
Maintenance
- Top-dress with fresh stone when the voids fill with mud and the pad stops cleaning tires.
- Keep vehicles from bypassing the exit.
- Inspect at every SWPPP inspection and after storms, and check the street at the exit daily.
- Repair washouts and potholes in the pad.
See sediment control BMPs for the full system.
Sources and official references
Last reviewed: October 25, 2026 · Free general education based on the Clean Water Act, EPA NPDES rules and the EPA Construction General Permit. Your governing permit (EPA, state, tribal or local) controls. This is not legal advice, not EPA-approved, and not a California QSP/QSD or other state credential, and it does not issue a certificate. Nothing you enter on this page is saved or sent.