Washington Oversize / Overweight Permit Requirements
Legal-without-permit dimension limits, escort and pilot car thresholds, height pole rules, daylight-only windows, and holiday restrictions for Washington oversize moves.
Legal limits without a permit
In Washington, you can move a load without an OSOW permit up to these dimensions on the Interstate and designated highways. Anything over the limits requires a permit (and may require escorts — see below).
| Dimension | Without a permit | Permit required when |
|---|---|---|
| Width | 8′6″ (federal limit) | Anything wider |
| Height | 13′6″ | Anything taller |
| Combo length | 75′0″ | Anything longer |
| Gross weight | 80,000 lb | Anything heavier |
Escort and pilot car thresholds
When permitted, the following escort or movement-restriction rules apply in Washington. Thresholds are conservative — your specific permit conditions may impose tighter limits depending on the route.
| Trigger | Dimension | Threshold | Detail |
|---|---|---|---|
| Rear pilot car | Length | 125'0" | Rear pilot required on 4+-lane divided highways for overall lengths over 125'. Superload classification applies at this threshold (WAC 468-38-075). |
| Front pilot car | Length | 105'0" | Rear escort required for lengths over 105' on 2-lane roads. On 4+-lane, rear escort required over 125' (WAC 468-38-075). |
| Front pilot car | Width | 20'0" | Front+rear pilots required on 4+-lane divided highways for widths over 20'. Lead+chase both required on all routes at this width (WAC 468-38-075). |
| Front pilot car | Front overhang | 20'0" front overhang | Front pilot required when front overhang exceeds 20' on 2-lane highways (WAC 468-38-075). |
| Rear pilot car | Rear overhang | 20'0" rear overhang | Rear pilot required when rear overhang exceeds 20' on 2-lane highways or when rear overhang exceeds 1/3 of trailer/load length (WAC 468-38-075). |
| Height pole | Height | 14'6" | Front pilot with height-clearance pole required for loads over 14'6" on all highway types. On 4+-lane roads, chase also required when load is over 12' wide (WAC 468-38-075). |
| Rear pilot car | Width | 14'0" | Rear pilot required on 4+-lane divided highways for widths 14'1"–20'. Single chase position until 20' threshold; lead+chase both required above 20' (WAC 468-38-075). |
| Daylight-only movement | Width | 12'0" | Loads outside the 12'W / 14'6"H / 105'L nighttime envelope require permit notation 'Nighttime movement approved'. Commuter curfew applies in Seattle-Everett, Tacoma, Olympia, Vancouver corridors (WAC 468-38-075). |
| Front pilot car | Width | 11'0" | Front+rear pilots required on 2-lane undivided highways when width exceeds 11'. Conservative threshold; always confirm route in permit (WAC 468-38-075). |
| Certified escort required | Width | 11'0" | Washington requires Evergreen Safety Council certification for all escort drivers; 3-year renewal. Reciprocal with AZ, CO, GA, MN, NC, OK, UT, VA (WAC 468-38-100). |
| Weekend / holiday restriction | Width | 11'0" | No movement on New Year's, Memorial Day, Independence Day, Labor Day, Thanksgiving + day after, Christmas. Restrictions begin noon of preceding day for all oversize loads (WAC 468-38-095). |
Stop tracking these rules by hand.
OverSizeTMS encodes the per-state escort and dimension rules for every state plus DC. Enter the load dimensions and route, and the platform tells you which permits, escorts, and time windows apply automatically.
See how it works →Last updated 2026-06-06. Cross-checked against the state admin code.