DOT Window Tint Regulations Explained

October 6, 2025

DOT window tint regulations are explained.

Trying to make sense of DOT window tint regulations can feel like driving through thick fog. But let’s cut through the haze. The core federal rule is actually pretty simple: your windshield and front side windows need to let at least 70% of light pass through.

This isn’t an arbitrary number. It’s a critical safety standard designed to give you a crystal-clear, unobstructed view of the road ahead.

Breaking Down the DOT Window Tint Regulations

When it comes to keeping your commercial vehicles on the right side of the law, knowing the foundational rules is step one to avoiding expensive tickets. The main federal regulation you need to have on your radar is FMCSA 393.60.

This rule establishes a clear benchmark for what the industry calls Visible Light Transmission, or VLT. A 70% VLT means the tint is very light, allowing the vast majority of visible light into the cab. The whole point is to guarantee you can see clearly in all conditions, from a bright summer day to a rainy night.

Why 70 Percent VLT Is the Magic Number

The 70% requirement is so important for a couple of key reasons. First and foremost, it ensures you can spot hazards, read road signs, and see other vehicles without your vision being impaired. It also allows law enforcement officers to make eye contact with you during a traffic stop, which is a big deal for their safety.

Now, this federal standard is just the baseline. This is where things get tricky. While the federal rule sets the national standard, your trucks must also comply with the tint laws in every single state they operate in. This creates a real headache for fleet managers, because a truck that’s perfectly legal in one state could get a violation the second it crosses into another.

The bottom line is this: your trucks have to follow whichever rule is stricter—federal or state. If a state demands a higher VLT percentage than the federal 70%, your vehicles must meet that state’s tougher requirement.

Key Considerations for Your Fleet

Staying on top of these regulations is a non-negotiable part of any solid fleet safety program. It’s about more than just picking a tint off a shelf; it’s about making smart choices that protect your people, your equipment, and your business.

Here’s what you need to keep in mind:

Federal Rule is the Floor: The 70% VLT is the absolute minimum for clarity on windshields and front side windows. You can’t go darker.
State Laws Add Layers: Every state has its own rulebook, and some are much stricter than the federal mandate.
Driver Vision is Everything: At the end of the day, these regulations all come back to one thing: preventing accidents by ensuring you can see what’s happening around you.

Beyond just staying compliant, there are plenty of good reasons to install window tint. To learn more about the upsides, check out this guide on the 6 Key Car Window Tinting Benefits from Fortress Security Films.

And remember, getting a handle on tinting rules is just one piece of the compliance puzzle. For a bigger picture, it’s worth reading up on overall DOT compliance for trucking companies to keep your entire operation running smoothly.

What VLT Means for Your Trucks

When you’re dealing with DOT window tint regulations, the single most important term to get your head around is Visible Light Transmission, or VLT.

Simply put, VLT measures the percentage of light that can pass through your window. A higher VLT number means a lighter tint. Think of it like a pair of sunglasses: a light yellow lens has a high VLT, while dark “limo tint” has a very low one.

The feds have set the magic number at 70% VLT for commercial trucks. This isn’t a suggestion—it’s a hard line that inspectors check for at every roadside stop.

How Inspectors Measure VLT

During a traffic stop or a weigh station check, officers don’t just eyeball your tint. They pull out a small, handheld device called a tint meter.

This gadget clamps onto the window and shoots a beam of light through it, instantly measuring the exact VLT percentage. If that reading dips below the legal limit—70% federally and often the same at the state level—you’re getting a violation.

It’s just one of the many things an officer will check. To get a better feel for what else they’re looking for, check out our guide on the Level 2 DOT inspection.

Here’s a common mistake that trips up a lot of people: assuming your truck’s factory glass is 100% clear. It’s not. Most factory glass already has a slight tint from the manufacturer, typically around 80-90% VLT, and you have to account for that.

This “hidden” factory tint can easily push a legal-looking aftermarket film into non-compliant territory.

The Hidden Math of DOT Window Tint Regulations

This is where fleets get into serious trouble. You might buy a tint film that’s rated at 75% VLT, thinking you’re playing it safe and staying well above the 70% federal minimum.

But that’s not how it works. You have to combine the VLT of the film with the VLT of your factory glass.

Let’s do the math:

Factory Glass VLT: Assume your truck’s glass is 85% (0.85).
Tint Film VLT: You apply a film with a 75% VLT (0.75).
Final VLT: You have to multiply these two numbers: 0.85 x 0.75 = 0.6375.

Your final VLT is actually 63.7%. That’s well below the legal 70% limit, and it’s a guaranteed violation waiting to happen.

This is exactly why the market for tinting films is shaped by these strict rules. In places like California and Texas, laws directly impact what tint you can legally install. For instance, California’s firm 70% VLT requirement on front side windows dictates which products are even viable for your fleet.

Federal Rules vs State Tint Laws

Just like with DOT mud flap regulations (or lack thereof), a compliance headache you’ll run into is the constant tug-of-war between federal and state tint laws. It’s a classic case where what’s perfectly legal on an interstate can suddenly become a violation when you exit onto a state highway. This confusion can lead to some expensive tickets for your fleet.

The key is really understanding how these two sets of rules play off each other.

The federal regulation, FMCSA 393.60, sets the baseline for dot window tint regulations. It establishes the absolute floor for window clarity at 70% VLT for the front side windows and the windshield (specifically, above the AS-1 line). Think of this as the non-negotiable, nationwide minimum your trucks must always meet.

But here’s the major catch with the federal rule: it also requires your commercial vehicles to comply with the laws of any state they are operating in. This is where things get really complicated, especially for long-haul operations.

Navigating the Patchwork of State Window Tint Laws

If a state law is stricter than the federal rule, you have to follow the state law. A truck that is perfectly compliant with the 70% VLT federal standard could cross a state line and suddenly be in violation. This creates a huge challenge when your routes span multiple states, each with different tint allowances.

For instance, some states might line up perfectly with the federal 70% rule. Others might have their own unique restrictions on tint color, reflectivity, or exactly where the tint can be placed. This patchwork system means you can’t just pick one standard and hope for the best.

The safest play here is to always default to the strictest rule in your operating area. If just one state on your route has a tougher standard than the federal one, that tougher standard becomes your new baseline for compliance across the board.

Staying on top of these details is crucial, as a simple tint violation can easily trigger a wider, more thorough inspection.

A Clear Comparison for Key States

To give you a practical tool, let’s compare the federal standard against the regulations in a few key states your trucks probably travel through. This table really highlights how quickly compliance can change from one border to the next.

Federal vs Key State Window Tint Regulations (VLT %)

Window Location	Federal FMCSA Rule	California	Texas	Florida
Windshield	Non-reflective tint above AS-1 Line	Non-reflective tint above AS-1 Line	Non-reflective tint above AS-1 Line or top 5″	Non-reflective tint above AS-1 Line
Front Side Windows	70% VLT	70% VLT (if combined with factory tint)	25% VLT	28% VLT
Rear Side Windows	No federal restriction	Any darkness allowed	Any darkness allowed	15% VLT
Rear Window	No federal restriction	Any darkness allowed	Any darkness allowed	15% VLT

As you can see, while California aligns perfectly with the federal rule for front side windows, Texas and Florida allow for significantly darker tints. This table just underscores how important it is to know the local rules for every single mile of your route.

States that are stricter than the DOT Window Tint Regulations (front windows)

Some states prohibit or severely limit front window tint beyond a narrow visor band. Notable examples include:

New Jersey: No aftermarket tint on the windshield or front side windows (medical waivers only).
Vermont: No tint on front side windows; windshield limited to the upper visor area.
New Hampshire: No tint on front side windows (medical waivers only); windshield limited to the upper visor area.
Michigan: Only a top band is allowed (generally the top 4 inches) on the windshield and front side windows; the rest must remain untinted.

Fleet window tint best practices

Standardize to no aftermarket film on the windshield and front side windows; use OEM glass that meets or exceeds 70% VLT.
For lanes touching NJ, VT, NH, or MI, spec no front tint (visor band only where allowed).
Keep proof of VLT (OEM glass specs or film certificate) with vehicle records.
Train drivers to understand that “legal at home” may not be legal across state lines.

How to Navigate Windshield Tint and the AS-1 Line

When it comes to DOT window tint regulations, your truck’s windshield is in a class all its own. It’s the most heavily regulated piece of glass on your entire vehicle, and for a very good reason—it’s the primary window you use to stay safe on the road.

Getting the windshield rules right is non-negotiable. The single most important term you need to burn into your memory is the AS-1 line.

What Is the AS-1 Line?

Go take a look at the upper corner of one of your truck’s windshields. You should see a small set of letters and numbers printed right on the glass. That AS-1 marking is a big deal—it indicates the highest point where any tinting is legally allowed under federal rules.

This line isn’t just some random marking. It’s a standardized benchmark across the entire auto industry that clearly designates the area above your main line of sight. This is also a key consideration for window crack violations as well.

Federal rules say you can apply a non-reflective tint in the area above this AS-1 line. The goal is simple: help you cut down on sun glare without putting a dark film directly in your field of vision. This is a critical detail that inspectors will zero in on during a roadside stop, and getting it wrong is an easy—and completely avoidable—violation.

Think of the AS-1 line as a strict boundary. Anything below it has to meet the 70% VLT requirement, which effectively means no aftermarket tint. Anything above it can have a darker, non-reflective film to help with glare.

Common Myths About Windshield Films

One of the most common myths out there is that “clear” UV films are perfectly legal to apply to the entire windshield. This is a dangerous assumption that can get you in hot water fast.

Even a film that looks totally clear to the naked eye can slightly lower the VLT of the glass. Let’s say your factory glass is at 85% VLT and you add a “clear” film that reduces it by just a few percentage points. When combined, you could easily dip below the legal 70% threshold. This is exactly the kind of nuance that trips up well-intentioned fleet managers during a Level 1 DOT inspection.

Another practical issue to watch out for is the dot matrix. That’s the border of small black dots you see on the edges of most modern windshields. When tint film is applied over this area, it can sometimes create a hazy or silvery border if the installation isn’t perfect. Not only does this look unprofessional, but it can also catch an inspector’s eye, prompting them to take a closer look at your tint. Mastering these small details is a key part of keeping your fleet compliant.

Understanding Tint Exemptions and Special Cases

While the DOT window tint regulations can feel pretty black and white, there are a few important exceptions to the rule. The most common one you’ll run into involves medical exemptions for people who have legitimate, diagnosed light-sensitive conditions.

But getting a waiver isn’t a free pass to slap on any tint you want. These are tightly controlled and always require official paperwork signed by a physician. If you have a driver with a medical need, they absolutely must keep that documentation in the cab at all times, ready to go for any inspection.

Medical Waivers and Interstate Challenges

Here’s where it gets tricky for fleets running across the country. A medical waiver that’s perfectly valid in your home state might not be worth the paper it’s printed on in the next state over. This creates a huge compliance trap for your interstate routes.

It’s on you to verify that a medical exemption is recognized in every single state your people operate in. Just assuming one state’s waiver is good everywhere is a risky gamble that can easily lead to violations and hefty fines.

Making sure all your paperwork is in order and planning routes with these details in mind is a core part of good fleet safety management.

More Flexibility for Rear Windows

Fleets like yours are trying to balance driver comfort with the hard realities of DOT window tint regulations. Fortunately, the rules are a lot more relaxed for windows that aren’t in your direct line of sight. This is where you can legally add some serious comfort for the person behind the wheel without cutting corners on safety.

The windows in the sleeper berth and the rear cab windows typically don’t fall under that strict federal 70% VLT rule. This opens the door to applying darker tints in these areas, which gives you:

Real Privacy: It turns the sleeper into a more comfortable, private space for mandatory rest periods.
Better Climate Control: Darker tints do a fantastic job of blocking solar heat, making the cab cooler and rest more restorative.
Less Glare: It cuts down on annoying glare that can hit screens or bounce around in the sleeper area.

Answers to Common Questions About the DOT Window Tint Regulations

Even after you get a handle on the basics, you’re probably still juggling a few questions about DOT window tint regulations. It’s totally normal.

Let’s walk through some of the most common questions fleet managers and safety directors ask. Getting these answers locked down can save you a world of headaches down the road.

Are Reflective Tints Allowed on My Trucks?

This one’s a hard no. Reflective or mirrored tints are pretty much banned across the board on the windshield and front side windows of commercial trucks. Federal and state rules are crystal clear and very strict on this point.

The reason is simple: safety. That mirror-like finish creates a blinding glare for other drivers, which is incredibly dangerous. It also makes it impossible for a law enforcement officer to see into the cab during a traffic stop, and that’s a major officer safety issue.

Your best bet is to stick exclusively to non-reflective tint films for every truck in your fleet. It’s always smart to double-check the film’s specs with your installer before it ever touches the glass.

What Are the Penalties for a Tint Violation?

Getting popped for illegal tint is more than just a minor inconvenience. The fallout can be surprisingly expensive and leave a mark on your company’s safety record.

While penalties differ from state to state, here’s what you can generally expect:

Fix-It Tickets: This is the best-case scenario. You’ll be required to remove the illegal tint and show proof that you’ve fixed the problem.
Hefty Fines: Fines can run anywhere from a hundred bucks to several hundred, depending on the state and how serious the violation is.
CSA Points: Despite only being a 1 Severity point violation, these do get logged against your CSA score, falling right into the Vehicle Maintenance BASIC. Rack up enough of these, and you’ll find yourself flagged for more inspections or even a full-blown DOT audit.
Forced Removal: Sometimes, an officer will make you scrape the tint off right there on the side of the road. This means frustrating downtime and potential damage to the window.

The only real way to dodge these headaches is to make sure every truck is compliant before it pulls out of the yard.

Do These Rules Apply if My Trucks Never Leave the State?

Yep, they sure do—but there’s a small catch. If your fleet runs exclusively within one state (intrastate), you’re mainly subject to that state’s commercial vehicle tint laws.

But don’t make the mistake of thinking local routes give you a free pass. Many states just adopt the federal FMCSA rules as their own standard anyway.

The safest, simplest strategy for any fleet, whether you’re running local or cross-country, is to just follow the strictest rule you might face. For tint, that almost always means sticking to the federal 70% VLT standard. This approach keeps your trucks ready for anything and prevents compliance issues, no matter where a load takes you.

What if I Get a Tint Violation Anyway?

Hey, it happens. Maybe you bought a used truck that wasn’t up to snuff, or someone decided to make a little “custom” modification without asking. If you get hit with a tint violation, the key is to act fast.

Get that illegal film removed immediately and document everything. Keep the repair order as proof that you corrected the violation. More importantly, treat it as a training moment. A violation is a flashing red light that your pre-trip inspection process or driver policies need to be tightened up to make sure it doesn’t happen again.

FAQ: DOT Window Tint Regulations for Commercial Motor Vehicles (CMVs)

What is the federal window tint rule for CMVs?

The windshield and the driver/passenger front side windows must allow at least 70% visible light transmission (VLT). There is no specific federal VLT limit for rear side or rear windows.

Does 70% VLT mean 70% tint?

No. VLT measures light that passes through. A higher number means clearer glass. To comply, the combined glass + film must be ≥70% VLT on the windshield and front side windows.

Are some states stricter than the federal rule?

Yes. Several states prohibit front window tint altogether or allow only a narrow visor band. If you run interstate, spec to the strictest state on your routes.

Do rear windows on CMVs have limits?

Federal rules don’t set a VLT for rear glass, but some states do. For a hassle-free national spec, many fleets keep rear glass near 70% VLT as well.

How do inspectors check VLT?

Officers use handheld tint meters. Compliance is based on the measured VLT of the installed glass/film—not what the product box claimed.

Does factory (OEM) glass count as “tint”?

Yes. OEM glass has its own VLT. Adding film lowers total VLT. Ensure the combined value still meets the ≥70% VLT requirement on the windshield and front side windows.

Do medical exemptions apply to CMVs?

Medical waivers are state-specific and may not apply to CMVs. If applicable, the driver must carry documentation and the vehicle must still meet any remaining safety rules.

Do pickup/van/hotshot rigs have to follow these rules?

If the vehicle is a CMV, the same federal requirements apply to its windshield and front side windows, regardless of body style.

What are the risks of noncompliance?

Expect citations, possible fix-it orders, delays at inspection, and audit exposure. Some jurisdictions can restrict operation until corrected.

What’s the best fleet spec to avoid problems?

Use OEM glass meeting ≥70% VLT and avoid aftermarket film on the windshield and front side windows. Keep proof of VLT (OEM specs, film certificates, or meter readings) with vehicle records and train drivers for interstate differences.

Regulatory References

These federal rules set the baseline window glazing and tint standards for CMVs and require compliance with stricter state laws where applicable.

Staying on top of complex DOT window tint regulations is just one piece of the massive safety puzzle. At My Safety Manager, we sweat the compliance details so you can focus on what you do best: running your business. Discover how our expert services can protect your fleet and your bottom line.