Before you hitch up and hit the highway, there’s a set of rules that most towing guides never talk about: the law. Towing regulations vary significantly from state to state, and many drivers are genuinely unaware that what’s legal at home may be a violation the moment they cross a state line. Speed limits, safety chain requirements, lighting, brake laws, length and width restrictions — all of it varies, and the consequences for violations range from a fix-it ticket to a significant fine to being ordered off the road entirely. This guide breaks down the most important towing laws by state and where to find the information that applies to your route.
Want structured, step-by-step training? Check out our guide to online towing courses to learn everything you need to tow with confidence.
Important note: This guide is intended for informational purposes and provides a general overview of common towing regulations. Laws change and enforcement varies. Always verify the current requirements for each state you plan to travel through using the official resources linked below. When in doubt, consult your state’s DMV or a legal professional.
Why Towing Laws by State Matter Beyond Just Safety
Towing compliance isn’t just about safety — it’s about liability. If you’re in an accident while towing and investigators find that your trailer wasn’t compliant with state law (wrong ball size, missing safety chains, non-functioning lights), your insurance company may use that as grounds to reduce or deny a claim. In some states, a trailer that’s not properly equipped is considered an illegal vehicle, and liability for any resulting accident may fall squarely on you. This is another reason why the basics — lights, chains, brakes, and proper hitch setup — aren’t optional.
Speed Limits While Towing
Most states have either a universal speed limit that applies to all vehicles, or a separate lower speed limit for vehicles towing trailers. California, for example, has a maximum speed limit of 55 mph for any vehicle towing a trailer — even on interstates where cars travel at 70. Texas has no separate towing speed limit in most zones, but some local and construction speed limits apply. Montana, Wyoming, and Nevada tend to have higher or uniform speed limits. The key takeaway: don’t assume the posted limit applies to you when towing. Check the state’s towing speed rules before your trip, especially if you’re crossing multiple states. For a quick state-by-state breakdown, see our guide to maximum towing speed by state.
Safety Chain Requirements
Nearly every state requires safety chains between the tow vehicle and trailer — but the specific requirements vary. Most states require crossed chains under the tongue (the X-pattern that cradles the tongue if the trailer detaches). Some states specify minimum chain strength relative to trailer GVWR. A few states require a minimum of two independent chains. The X-crossing requirement is both a legal standard in most states and simply the safest configuration — it’s the right way to attach safety chains regardless of local law. For more on proper hitch setup and safety chain attachment, see our guide on The Pre-Trip Towing Checklist Every Driver Needs.
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Trailer Lighting Requirements
Federal law establishes baseline trailer lighting requirements — tail lights, brake lights, and turn signals — that all states adopt. However, longer trailers (typically over 30 feet) require additional side marker lights and reflectors. Trailers over 80 inches wide require side marker lights as well. Most states require that trailer lighting match the tow vehicle’s signals — if your truck signals right, the trailer must also signal right. Electrical failures that leave a trailer running without brake lights or turn signals are both dangerous and illegal in every state. Keep your trailer wiring in good condition and test lights before every trip. Our guide on How to Wire Trailer Lights covers diagnosis and repair.
Trailer Brake Requirements
This is where state laws vary most significantly. Most states require trailer brakes when the trailer’s loaded weight exceeds a threshold — typically between 1,500 and 3,000 lbs depending on the state. California requires brakes on any trailer with a loaded weight over 1,500 lbs. Texas requires them over 4,500 lbs. Washington state requires them over 3,000 lbs. Some states also require a breakaway brake system — a battery-powered emergency brake that activates if the trailer separates from the tow vehicle. If you’re towing a trailer that weighs more than a few thousand pounds and you’re not using trailer brakes, you’re likely in violation of the law in multiple states — and creating a genuinely dangerous braking situation. See our complete guide on Electric Trailer Brakes and Brake Controllers for setup and compliance guidance.
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When Are Trailer Brakes Required?
Most states require brakes on the trailer once its gross weight (trailer plus cargo) passes a set threshold. The most common thresholds fall between 1,500 and 3,000 lb. California, for example, starts at 1,500 lb. A few states set the line higher.
- Electric brakes need a controller. If your trailer has electric brakes, your truck needs a working brake controller mounted in the cab.
- Breakaway systems: many states also require a breakaway switch and battery on braked trailers. It applies the trailer brakes automatically if the trailer comes off the hitch.
- Use the loaded weight. A light empty trailer can cross the threshold once it is loaded. Go by the GVWR or the actual scale weight, not the empty weight.
- Multi-state trips: if any state on your route has a lower threshold, set up your rig to meet that one.
DMV caveat: thresholds and wording (gross weight vs. GVWR, brakes on one axle vs. all wheels) differ by state. Confirm with your state DMV before you tow.
Length, Width, and Height Restrictions
Most states follow federal guidelines that limit combination vehicle length (tow vehicle plus trailer) to 65 feet on most roads, with some exceptions for specific configurations. However, trailer-only length limits also apply — typically 40–53 feet for single trailers. Width is almost universally restricted to 8.5 feet (102 inches) for non-permit loads. Height limits are typically 13.5–14 feet for unpermitted loads. For recreational towing (typical utility trailers, boat trailers, travel trailers, fifth wheels), these limits rarely come into play. But if you’re hauling an oversized load — a wide equipment trailer, a long flatbed — you need to research permit requirements for every state on your route well in advance.
Maximum Towing Length by State (Combined Truck + Trailer)
For a regular (non-commercial) pickup towing a trailer, 65 feet of combined length is the most common limit, measured bumper to bumper from the front of the truck to the back of the trailer.
| Rule | Typical figure |
|---|---|
| Combined truck + trailer (most states) | 65 ft |
| California, combined | 65 ft |
| Some states (often Western states) | Up to 70–75 ft |
| Trailer width (nearly all states) | 8.5 ft (102 in) without a permit |
What this means in practice: a crew-cab long-bed pickup is roughly 20–22 ft long. A 25 ft travel trailer plus its tongue keeps you well under 65 ft. Length limits mostly matter for big fifth wheels, long toy haulers and “triple towing” (truck + fifth wheel + boat), which many states restrict or ban.
Verify with your state DMV. Limits change, and states measure differently (overall length vs. trailer-only length). Some states also set separate limits for the trailer alone. Check the DMV or DOT site for your home state and every state on your route.
Mirror Requirements
Many states require that a driver have an unobstructed view to the rear of the vehicle — and specifically require towing mirrors when the trailer is wider than the tow vehicle. If your trailer blocks your rear view with standard mirrors, you’re legally required to use extended or towing mirrors in most states. Beyond the legal requirement, towing without adequate rear visibility is genuinely dangerous. See our full guide on Towing Mirrors for recommendations on the right mirror setup for different trailer widths.
Are Towing Mirrors Required?
Usually, yes, when your trailer blocks your view to the rear. Most states do not name a specific mirror. Instead they require a clear view of the road behind you, typically about 200 feet back, on both sides. Once a trailer is wider than your truck, factory mirrors usually cannot give you that view, so extended towing mirrors become the legal and practical fix.
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- Simple test: sit in the driver’s seat. If you cannot see down both sides of the trailer and the lane behind it, you need extended mirrors.
- Clip-on vs. replacement: both can comply. What matters is a stable, vibration-free view.
- Do not over-extend: some states limit how far mirrors may stick out past the trailer’s width. Fold or retract them when you are not towing.
Requirements vary, so check your state DMV.
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Trailer Registration: The Rule People Forget
Most states require trailers to be registered and plated, and the rules vary: some require annual renewal, others offer multi-year or permanent registration for certain trailer types. Registration makes your trailer identifiable after an accident or theft. Keep it current and carry proof with you whenever you tow.
Preparing for a Cross-State Trip
Your trailer is registered in your home state, but on the road you must follow the laws of every state you drive through. Speed limits, brake thresholds and mirror rules can change at the state line. Before a multi-state trip:
- Look up the towing rules for each state on your route (DMV or state transportation department).
- Confirm your vehicle and trailer registrations are current.
- Check that trailer lights, brakes and the breakaway system work and comply.
- Carry your registration and proof of insurance where you can reach them.
Where to Check State-Specific Towing Laws
The most reliable source for current towing regulations in each state is that state’s Department of Motor Vehicles (DMV) or Department of Transportation (DOT) website. Search for “[state name] trailer towing regulations” or “[state name] DMV trailer requirements” to find the relevant statutes. For multi-state trips, the American Automobile Association (AAA) publishes a digest of state towing laws that many members find useful. The Federal Motor Carrier Safety Administration (FMCSA) website covers federal regulations that apply to commercial towing and provide baseline standards that most state laws build on.
The Most Common Violations to Avoid
Based on what law enforcement most commonly cites during towing stops, these are the violations to be most aware of: trailer lights that don’t work (especially brake lights), exceeding towing speed limits (particularly in California), towing a trailer that requires brakes without a brake controller, using safety chains that are too long or improperly attached, and towing a trailer wider than the tow vehicle’s mirrors without extended towing mirrors. All of these are preventable with proper equipment and a quick pre-trip inspection.
The Bottom Line
The law varies by state, and the responsibility for knowing those laws before you cross state lines falls on you as the driver. The good news is that most of the legal requirements — proper lights, working brakes, correct safety chains, adequate mirrors — are also simply the safest way to tow. If your rig is set up correctly for safety, you’re probably already in compliance with most of the law. The areas to double-check before a multi-state trip are speed limits, specific brake weight thresholds, and any size or permit requirements for your trailer type.
TowPro Academy’s truck towing course teaches you the right way to set up and operate a towing rig — which also happens to be the legal way. 51 video lessons for $79 through Oct 31 (regularly $99).
Further Reading
- The Pre-Trip Towing Checklist Every Driver Needs
- Electric Trailer Brakes and Brake Controllers: What Every Tower Needs to Know
- Towing Mirrors: Do You Need Them and Which Type Is Right for Your Truck?
- How to Wire Trailer Lights: A Step-by-Step Guide
Wondering whether a heavy camper or fifth wheel needs a different license class? See our guide: Do You Need a Special License to Tow a Trailer?
Read Next
- What Is GVWR?
- Complete Beginner’s Guide to Towing
- Towing Glossary: A–Z Definitions for Every Tower
- New to Towing? Start Here
- Complete Beginner’s Guide to Trailer Towing
Laws Cover the Rules, Not the Skills
Knowing your state’s towing speed limit or license threshold won’t teach you how to load for correct tongue weight, set your mirrors or back into a campsite. Those are hands-on skills. The TowPro Academy online towing course teaches them step by step. It ends in a certificate of completion, not a government license, so always check your state’s DMV for the legal requirements.
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Frequently Asked Questions
Do towing laws vary by state?
Yes. States differ on maximum trailer width and length, towing speed limits, braking requirements, safety chain rules, and whether passengers may ride in a towed unit. Always check the laws for every state on your route.
When does a trailer need its own brakes?
Most states require trailer brakes once the trailer’s gross weight passes a set threshold, commonly around 1,500 to 3,000 pounds. The exact weight and brake type required depend on the state.
Are trailer safety chains required by law?
In nearly every state, yes. Safety chains must be crossed under the coupler and rated to hold the trailer’s weight if the hitch fails. Some states also mandate breakaway systems on heavier trailers.
Can passengers ride in a towed trailer or fifth wheel?
It depends on the state. Some allow occupants in fifth wheels with certain safety features, while many prohibit riding in any towed trailer. Confirm the rule in each state you’ll travel through.
Do I need to register my trailer in every state I travel to?
No. You register in your home state, but you must follow the towing laws of each state you drive through.
How often do I need to renew my trailer registration?
It depends on the state. Some require annual renewal, while others offer multi-year or permanent registration for certain trailers. Check with your state’s DMV.
What is the maximum towing length in most states?
65 feet of combined truck and trailer length is the most common limit, including in California. Some states allow 70–75 feet. Check your state DMV for the exact figure.
Are towing mirrors required by law?
In most states, yes, if the trailer blocks your rear view. You must be able to see the road behind you on both sides. If your factory mirrors cannot do that, you need extended towing mirrors.
At what weight are trailer brakes required?
Commonly when the trailer’s gross weight passes 1,500 to 3,000 lb, depending on the state. California’s threshold is 1,500 lb. Many states also require a breakaway system. Verify with your DMV.
Is a 25 ft trailer legal to tow without a permit?
Almost always. A 25 ft trailer behind a full-size pickup typically totals 45–50 ft, well under the common 65 ft limit. You still need to meet your state’s brake, lighting, mirror and registration rules.
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