What is the Max Height on a Flatbed? Semi-Truck Clearance Heights by State

Legal heights for flatbed loads are different in every state. In most eastern states, the maximum clearance height for a semi-truck and trailer is 13 feet, 6 inches. In many western states, the maximum clearance height can be up to 14 feet, 6 inches.

Before your shipment hits the road, it’s important you know when your shipment may be considered too tall for standard transport — and what options you have if it does exceed legal height limits.

Maximum Vehicle Height by State

Legal Semi-Truck Height Limits West of the Mississippi River

In general, legal freight height limits are often higher in states west of the Mississippi River, though there are a few exceptions. Limits also tend to vary more by state in the Western region, which makes it important to confirm the requirements for each state on your route.

Legal Semi-Truck Height Limits East of the Mississippi River

East of the Mississippi River, freight height limits are more standard. In most eastern states, the maximum legal height is 13 feet, 6 inches. However, shippers should still confirm the requirements for each state the shipment will travel through before assuming a load can move legally.

Why Do Maximum Load Heights Vary Between States?

Legal freight height limits vary between states because infrastructure, population density, and local regulations are different across the country. One of the clearest patterns is the difference between states east and west of the Mississippi River.

While these regional patterns can help explain why legal freight height limits vary, it’s still critical to still confirm each state’s maximum semi clearance height before your shipment travels through it.

How to Tell if Freight Exceeds Legal Height Limits

To determine whether your freight is within legal height limits, you need an accurate measurement of the full truck, trailer, and freight height.

How to Measure Freight Height

Freight height is measured from the ground to the tallest point of the load. This measurement needs to include the trailer, tires, freight, and anything the freight is sitting on, such as a pallet or crate.

The easiest way to measure freight height is by hooking a tape measure to the highest point of the load and then reaching the tape measure to the ground. If there is any question about the tallest point, measure multiple high points and take the highest measurement.

It is critical to measure precisely. This is not the time to estimate or make assumptions. A discrepancy of even a few inches could affect whether the shipment clears bridges or other overhead obstructions.

Tips for Measuring Freight Height

• Measure on level ground. Uneven ground can affect the accuracy of your measurement.
• Measure the loaded truck and trailer. Do not rely on specs, drawings, or estimated freight dimensions. Measure the secured shipment before the driver leaves the point of origin.
• Include pallets, crates, and platforms. Anything the freight rests on adds height and should be included in the measurement.
• Measure more than one high point. If the load is uneven, measuring multiple high points helps you identify the true tallest point.
• Do not round down. Even small inaccuracies can affect whether your load can move legally.
• Confirm all freight dimensions. Height is not the only measurement that matters. Accurate length, width, and weight are also critical for avoiding delays, added fees, permit issues, and safety risks.

What to Do if Your Freight Exceeds Legal Height Limits

If your freight exceeds legal height limits, it may still be able to move legally with the right planning. Depending on the shipment, your options may include:

1. Divide Your Freight

If possible, disassemble your freight into smaller pieces to reduce the total height.

Keep in mind that those pieces may need to move as separate shipments. They cannot be stacked on top of each other to fit on one trailer, because that would be considered divisible freight. Divisible freight cannot be permitted as an oversized load and must be split across multiple vehicles for transit.

2. Change Your Trailer Type

The type of trailer you use can affect the total height of your shipment. Choosing a trailer with a lower deck height may reduce how tall the freight sits once it is loaded, helping the shipment stay within legal height limits.

A standard flatbed trailer is typically 5 feet high. Freight up to 8 feet, 6 inches tall can be transported through any state via standard flatbed. Some freight, like shipping containers, are specially designed to meet legal load limits on a flatbed.

If your freight is taller than 8 feet, 6 inches, you may need more specialized trailer equipment, such as:

Keep in mind that specialized equipment typically costs more per mile than a standard flatbed trailer but sometimes is the only option for moving overheight freight.

Talk with an experienced transportation provider to determine the best trailer type for your shipment and confirm whether the equipment you need is available.

3. Obtain an Oversized Load Permit

Freight that is over-dimensional in height, length, width, or weight can often still be transported legally with the appropriate permits.

Because height limits vary by state, the point at which an oversize/overweight permit is required also varies by state. If your over-dimensional shipment is travelling through multiple states, you will need to obtain a permit for every state it travels through.

Note that in many jurisdictions, a load will not be permitted as oversize on a standard flatbed when a lower-profile trailer is available. The expectation is that the smaller trailer will be specified, rather than the full-height flatbed.

Oversize permits also only apply up to certain size limits. For height, that limit is often around 17 feet. Freight taller than that may be considered heavy haul freight, which may require even more specialized equipment and additional support.

4. Transport Your Freight by Barge

In some urban areas, especially along the east coast, there may not be a legal over-the-road route available for over-dimensional freight. In these cases, the shipment may need to travel most of the distance by barge before it is transloaded onto a truck for the final leg of the shipment.

Plan Ahead Before Moving Overheight Freight

Every shipment takes planning and coordination, but overheight freight adds complexity and requires extra attention. Bridges, power lines, and other overhead obstructions cannot simply be moved, so prior route planning is essential.

Overheight freight may also require permits, pilot cars, or specialized trailer capacity, which can make it more expensive to move than a legal load.

That’s why it’s so important to plan ahead to make sure:

1. Your shipment has the required permits to move legally.
2. Your route accounts for low-clearance obstructions before the load is in transit.
3. Any required pilot cars, specialized equipment, or other support can be arranged before the shipment moves.

While planning for overheight freight can be inconvenient, the cost of not planning can be much greater.

Frequently Asked Questions

Shipping an Over-Dimensional Load? Get Expert Guidance

Since 1955, Anderson Trucking Service (ATS) has helped shippers plan complex freight moves, including over-dimensional shipments that require state-specific permits, route planning, and additional coordination.

Have a load that exceeds legal height limits? Contact our experienced team before your freight moves!

Related Resources for Oversized Freight Planning

For more guidance on transporting complex freight, subscribe to our Learning Hub, where we regularly share trucking industry updates, shipping tips, and other helpful resources. To get started, here are a few related articles:

• Divisible and Non-Divisible Loads Explained
• Can I Overhang Freight on a Flatbed Trailer?
• How to Get Oversized Load Permits For Your Freight
• Common Flatbed Trailers