Winter changes everything - road conditions, visibility, traffic flow, and most importantly, permit-approved routes for oversize and overweight loads.

A route that was safe in September can become unusable or legally restricted in December when frost laws, black ice, and high-wind corridors come into play. One bad routing decision can mean hours of delays, safety risks, and even a rejected OSOW permit.

Here’s why smart winter route planning matters more than any other season — and the roads oversize carriers should avoid when temperatures drop.

Why Winter Route Planning Is Critical for Oversize Loads

1. Weather Can Close a Legal Route Overnight

Snowstorms, freezing rain, and black ice can force DOTs to:

• Shut down mountain passes

• Restrict travel hours

• Ban oversize movement temporarily

• Require pilot cars where they weren’t needed before

Winter is unpredictable - your routes can’t be.

2. Frost Laws Reduce Weight Limits on Key Roads

When the ground thaws and weakens, many northern states enforce Seasonal Weight Restrictions (frost laws). These impact:

• County roads

• Secondary highways

• Non-designated state routes

Even permitted loads must follow restricted weight rules. If your haul crosses frost-law states like Minnesota, North Dakota, Michigan, or Wisconsin, your regular route may no longer be legal.

3. Mountain Passes Become High-Risk Zones

Winter conditions make certain passes extremely hazardous, especially for wide, tall, or heavy loads.
High-risk examples include:

• I-70 through Colorado

• Snoqualmie Pass in Washington

• Donner Pass in California

• Montana’s Homestake Pass

Steep grades + snow = rollover risk, brake fade, and jackknifes.
A safer detour is almost always faster than a dangerous shortcut.

4. Wind Corridors Are More Dangerous in Winter

Oversize loads catch more wind — and winter produces stronger, more unpredictable gusts.
High-risk wind corridors include:

• Wyoming (I-80 and US-287)

• New Mexico & West Texas plains

• Oklahoma panhandle

Loads over 12 ft wide or 14 ft tall are especially vulnerable.

5. Construction Zones Don’t Go Away in Winter

Even in cold states, bridge and road projects continue through winter.
With narrower lanes and limited shoulder space, oversize vehicles often cannot safely pass these areas.
Winter reduces maneuvering room even more due to snow accumulation.

High-Risk Roads to Avoid in Winter (Oversize Edition)

1. Narrow Rural County Roads

Often untreated, unplowed, or weight-restricted.

2. Mountain Passes Above 5,000 ft Elevation

High risk of ice, heavy snow, and whiteout conditions.

3. Long Unprotected Bridges

Crosswinds + oversize height = immediate rollover danger.

4. Roads Without Adequate Turning Radius

Snowbanks reduce space for wide-swing turns.

5. High-Traffic Holiday Corridors

Especially around major cities — congestion delays permit schedules.

How Proper Route Planning Avoids Winter Delays

✔ Prevents permit rejections

DOTs deny OSOW permits if your selected route is unsafe during winter months.

✔ Avoids forced detours

Changing a route mid-trip often requires a completely new permit.

✔ Reduces safety risks

Black ice, blowing snow, and visibility drops demand pre-planned safe paths.

✔ Saves money

Every hour stuck in weather or at a closure burns fuel, wages, and time.

Psychology trigger: Control — Winter is unpredictable, but your plan doesn’t have to be.

Winter Route Planning Tips for Oversize Carriers

1. Check Weather + DOT updates daily

Conditions change fast — especially in mountain states.

2. Use professional routing services

Permit providers like OSOWPermits use systems that check:

• Height restrictions

• Bridge weights

• Frost zones

• Road closures

• Escort requirements

• Construction maps

3. Build a “Plan B” route

Always have one alternate route ready in winter.

4. Avoid tight schedules

Winter delays are normal — pad your delivery windows.

5. Confirm escort requirements

Some states require escorts only during winter months.

6. Keep drivers winter-ready

Chains, emergency kits, warm gear, and extra securement checks.

Winter isn’t the time to gamble with your oversize routes. Snow, ice, frost laws, and surprise closures make winter hauling far more dangerous — but also completely manageable with the right planning.

👉 Let OSOWPermits build your winter-safe route
Our team monitors weather, restrictions, frost laws, and DOT updates in real time — ensuring your permit and route stay legal from start to finish.