Can You Overhang on a Step Deck Trailer? 5 Steps to Ensure Compliance

ATS step deck trailer

For experienced carriers and industry newbies alike, navigating the rules for overhanging cargo on step deck trailers can be especially tricky. 

While federal guidelines provide a baseline, specific limits vary widely from state to state, and step deck trailers themselves present their own set of unique challenges. 

These versatile trailers are designed to accommodate taller and more specialized freight, but can sometimes fall into a gray area when measuring overhang and complying with dimensional limits.

Whether you're a seasoned carrier or new to hauling on a step deck, understanding the federal and state rules regarding overhang — and how they apply to this specific trailer type — is critical to avoiding delays, fines, and safety issues. 

Anderson Trucking Service (ATS) has been helping shippers and carriers navigate the transportation industry for 70 years. We’re well-versed in the complexities of compliance, including those relating to overhang on open-deck trailers.

In this guide, we’ll break down the nuances of step deck overhang rules and offer practical tips for staying compliant on the road.

Can You Overhang on a Step Deck?

The short answer is yes: You can legally overhang on a step deck trailer in some states — but the specifics and limitations depend on trailer length, amount of overhang, load configuration, and the rules of the state(s) through which the load will move.

Like all freight that moves in the U.S., step deck loads are subject to federal transportation regulations as well as state-specific rules. They were designed to keep truck drivers, their loads, the motoring public, and infrastructure safe.

Due to a combination of regulatory subtleties, physical differences between the trailer types, and variations in how these rules are interpreted and enforced, there can be some confusion over how certain rules apply to open-deck trailers (like step decks) specifically. 

Of the two, flatbeds are the more common trailer type, so many carriers have a higher degree of familiarity with them. Step decks, by comparison, are more specialized and less commonly used. 

Related: Can I Overhang Freight on a Flatbed Trailer?

While flatbeds and step decks are both open-deck trailer types, there are a variety of design differences between them, including: 

  • One deck surface vs. two
  • Distance from the trailer kingpin to the rear axles
  • Distance from the axles to the end of the trailer
  • How far the deck extends
  • Placement of one or more items on the deck

These variables can create uncertainty about whether a step deck load’s rear overhang measurement is legal to haul without a permit — or,  in some cases, whether it’s legal to haul at all.

Furthermore, the complexity (and sometimes ambiguity) of federal and state-level regulations also complicate compliance for carriers. We’ll dive deeper into those nuances next.

General Federal Guidelines for Overhang

The minimum lengths (trailers and overhang) that states must allow on the National Network are regulated under the Federal Size and Weight Regulations for Commercial Vehicles set by the Federal Highway Administration (FHWA). 

The minimum semi-trailer length states must allow is 48 feet. Federal law also specifies that states must allow automobile and boat transporters a minimum of 4 feet of rear cargo overhang and a minimum of 3 feet of front cargo overhang. 

If your trailer is 53 feet or longer, you cannot legally overhang without a permit in most states. While there are some exceptions to this rule, the vast majority of states legally allow 53-foot trailers on designated roadways.

Whether front and rear overhang is allowed on 53-foot trailers also varies when freight is legally divisible, or when loaded end-to-end. 

The federal guidelines for overhang are a general point of reference, as there are exceptions to these rules that vary greatly depending on the state.

State-Specific Rules

While federal guidelines are universal to the National Network, state-specific rules for trailers, overhang, and roadways differ.

Some states have clear overhang allowances for truck-tractor semi-trailer combinations simply because they are common. Open-deck trailers, being more specialized, are not always explicitly addressed in state regulations, which leads to questions about interpretation and enforcement.

It’s important to be aware of the legal dimensions and rules for trailers with overhang in each state you will be traveling through on your route. The best, most reliable source for state-specific regulations is the state’s Department of Transportation (DOT).

The state’s Commercial Vehicle Enforcement (CVE) division, oversize permit office, and Department of Motor Vehicles (DMV) are also trustworthy resources.

Most states will have a permitting manual or rules documentation readily available online via its DOT website. As part of your regular route planning for any load you intend to overhang on a step deck, check the official rules for each state the load will pass through. 

This proactive step will help ensure you are not caught off-guard by variations from the federal guidelines, which could cause significant delays and unexpected costs associated with additional permitting. 

Green ATS step deck

Common State-Specific Variations

While states must adhere to the federal guidelines, there are many state-specific rules regarding overhang, trailer length, kingpin limits, overall length, and designated and non-designated highways.

If your freight exceeds a state’s overhang rules, it will need a permit to travel through that state legally. Permits for over-length freight allow overhangs beyond the standard limits, but may come with additional restrictions, such as daytime travel limits, flags, signs, or pilot escorts.

Here are some of the most common state-specific variations to overhang rules:

  • Rear Overhang Limits: While the federal rules require a minimum of 4 feet of rear overhang for specific equipment (which many states take as their maximum legal limit), some states choose to allow longer overhangs. Examples include but are not limited to:
    • Utah — 6-foot rear overhang
    • Arizona — 6-foot rear overhang
    • Colorado — 10-foot rear overhang

  • Front Overhang Variances: The federal rules allow a minimum of a three-foot front overhang (forward of the Truck Motor Vehicle), and many states adhere to this. How front overhang is defined varies by state; some states specify trailer and cargo length overhang separately, while others specify as a combination.

  • Special Cargo Exceptions: Some states provide exceptions for specific cargo types that can’t be easily shortened or divided, like metal poles, pipes, or lumber. These exceptions typically allow longer overhangs with appropriate markings like red flags or lights. Examples include but are not limited to:
    • California
    • Arkansas
    • Illinois
    • Ohio
    • West Virginia

  • End-to-End Loading Exceptions: Loading multiple pieces of freight end-to-end can change the way states apply overhang rules. For instance:
    • Most states will allow rear overhang on end-to-end flatbed loads up to a certain limit, particularly on 48-foot trailers. (Remember, a trailer 53-feet long or longer typically cannot haul two pieces end-to-end with rear overhang.)

    • Legal front trailer overhang on end-to-end freight is also commonly allowed, particularly on 48-foot trailers or to the state’s limit.

  • Overall Vehicle Length Limits: Some states choose to focus their regulations on limiting the overall length of the vehicle (including any overhang) rather than just the length of the overhang. Examples include but are not limited to:
    • Alabama
    • Florida
    • Indiana
    • Minnesota
    • North Dakota
    • Wisconsin

It should be noted that, even within this category, there are variances. Some states enforce both overall vehicle length limits and overhang length limits. Some impose trailer length maximums (from kingpin to end) but not overall vehicle length limits. Still others do the inverse, enforcing overall length limits only on trailers over a certain size.

These are just some of the common variations found in state overhang guidelines. To find a specific state’s overhang regulations, always check its official DOT and DMV websites.

Practical Steps to Ensure Overhang Compliance

Ensuring compliance with overhang limits on step deck trailers requires proactivity and attention to detail. From researching your routes to marking your loads properly, there are several simple measures that can help you stay on the right side of the law and avoid fines, delays, and safety risks. 

Apply for Permits

If your load exceeds the limits mandated by the states on your route, this step is non-negotiable. Many states offer online applications for oversize/overweight permits. While many permit applications are processed quickly, others can take days or even weeks to be approved — so submit in advance to avoid delays.

Related: How to Get Oversized Load Permits for Your Freight (3 Easy Steps)

Check Your Specs

Overhang rules are often tied to the overall length of the trailer and cargo combined. Check your trailer’s specs and that of the load you’re hauling well in advance of hitting the road to avoid any last-minute issues.

Load Planning

Moving an interstate load? Plan for your load to comply with the strictest state regulations you’ll encounter as you travel. This will help you avoid fines or delays all along your route.

Mark Overhanging Loads 

Use red flags (daytime) and red or amber lights (nighttime) for loads extending beyond the legal limits. Not sure if the states on your route mandate flags or lights? Err on the side of caution. It’s better to use them and not need them than need them and not have them! 

Research State Regulations

Use state-specific DOT websites for each of the states you’ll be traveling through to better understand their unique requirements and ensure compliance.

Step Deck Overhang Compliance: What to Remember Before You Haul

Step decks are an invaluable tool for hauling tall and specialized freight, but they demand extra attention to detail when it comes to load placement, height, and overhang.

Overhang regulations for step deck trailers may feel like a maze of federal guidelines, state-specific rules, and unique exceptions, but with the right preparation, compliance doesn’t have to be a headache. 

The key to success lies in thorough route planning, accurate load measurements, and staying informed about the specific regulations in every state you’ll pass through. Whenever your load exceeds the standard limits, securing the proper permits and adhering to marking requirements, like flags and lights, are essential steps for both safety and legality.

By understanding the basic federal limits, researching state variations, and proactively planning your load and route, you can enjoy a smoother journey and avoid costly delays or penalties.

If and when your freight exceeds overhang limits, you may find yourself looking for a permit company to help you secure the necessary permitting.

Start with our article on 6 Oversize/Overweight Permit Companies to Consider Using in 2025. You’ll come away with some great options and our top tips for making your permit company selection with confidence. 

Tags: Safety, Heavy Haul Shipping, Flatbed Shipping, Oversized Shipping, Specialized Flatbed Shipping, Over Dimensional Shipping, Carrier Resources, Trailer Types

Joanna Jungels

Written by Joanna Jungels

Joanna Jungels began her career with ATS in 2005 as a Fleet Manager. Soon after, she was promoted to oversee and enhance a growing OS/OW permitting team which created a system to retain and output rules and requirements for both state and local entities. Today, Joanna regularly attends state transportation meetings, and currently serves as chair of the Permit Policy Committee at the Specialized Carriers & Rigging Association, where she advocates for, and promotes the importance of, creating useful resources to better understand and increase awareness around the complexities of oversized freight. In her role at ATS, Joanna enjoys working with others to brainstorm, solve problems and learn new things while continually striving to improve the processes and resources available to ATS' customers.

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