Trucks & Bridges: Know Your Truck's Height and Weight

Tips to navigate over and under bridges safely

A large white box truck drives over a bridge through a lush green forest.
It only takes one slight miscalculation near a bridge to put yourself — and your truck — in serious peril. Disobey low-clearance warnings and you could suffer a bridge strike that damages your vehicle and its cargo. Ignore posted bridge weight limits and you could endanger yourself and other motorists.

Use these tips to navigate over and under bridges safely.

1. Know your truck’s height

Check your vehicle for decals listing clearance height. On Penske trucks, these stickers are located on the front windshield and the side of the truck. They’re viewable from the driver’s side mirror, so drivers can check their clearance before proceeding under an overpass.

2. Know your truck’s weight

Look for the decal on the driver-side door jamb that lists the Gross Vehicle Weight Rating (GVWR), which is your truck’s maximum weight. For exact weight measurements based on load, use weigh stations, Certified Automated Truck (CAT) scales at truck stops, or the CAT Weigh My Truck app.

3. Watch for signs

Low-clearance bridges are typically marked with signs listing the height of the overpass. Weak bridges are also marked with signs. Some list maximum GVWR limits. Others show specific weight limits for 2-axle, 3-axle and 5-axle combination vehicles. Always read warning signs to ensure you can proceed safely.

4. Allow for some leeway

Add at least a half-foot buffer to your truck height. This will account for things like road resurfacing and hard-packed snow and ice, which can add inches to pavement. For truck weight, add about a 5% buffer to your total GVWR for variables like the amount of fuel in your tank and the amount of air pressure in your tires.

5. Use a truck driver-specific GPS to plan your main route & backup routes

Newer commercial GPS systems let you filter routes based on your truck’s height and weight. They’ll also give you trucker-specific information and alerts about road closures and detours.

6. Stay on truck-friendly routes if possible

Interstates follow federal standards for high clearances, and bridges on interstates are built to handle CMV weights. The same is not true for back roads and side streets. Eighty percent of the nation’s bridges with weight restrictions are on local roadways, according to the U.S. Department of Transportation. DOT-specific GPS’s can help keep you on the correct route, allowing you to enter your truck dimensions keeping you clear of low overhangs. Check with the manufacturer and know the features and limitations of your unit.

7. Keep your cool

Rushing and fatigue can cause you to make a crucial mistake on or near a bridge. Reduce your speed and stay calm behind the wheel to avoid problems. And never drive distracted.

8. When in doubt, don’t cross

If you’re not sure you can proceed safely, pull over to a safe spot and double-check your height or weight.

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