Car Mods: Street Legal, Locally Illegal?

Not only might an accessorized look that hits the mark in San Diego not play in Peoria, it might not be legal there. And take an off-road lifted, window-tinted, modified truck to quaint, coastal New England, and you might just get a ticket.

Local and state rules for accessories and vehicle modification vary greatly. States can’t issue regulations that conflict with federal standards (FMVSS), which set performance requirements, not design requirements for vehicles; but states are free to establish their own regulations and rules where ones from the federal government don’t already exist. And they certainly have.

Beyond obvious upkeep issues like rust, leaky exhausts, and headlights that don’t work, here are ten rather unexpected reasons why, within the U.S. your vehicle might be street-legal in one place and illegal in another.

This one’s frustrating. Almost every state law has its own rules on window tinting -- especially light transmittance, usually given as a percentage -- and they’re all over the place. Regulations typically range from 50 or 70 percent for the driver’s side in much of the upper Midwest and East Coast (a very light tint) to less than 30 percent in many Southern states. To complicate matters more, some states place more of a restriction on the driver’s side window. Get a lighter tint in the first place, and you’re much less likely to run into trouble when you move and re-register.

Your vehicle upgrade could be as simple as a new exhaust pipe or muffler, a resonator, or even an exhaust tip that’s mostly decorative, yet if the new setup is noticeably louder than the stock system you might be bait for a citation -- depending greatly on where you are. According to Steve McDonald, vice president for government affairs for the Specialty Equipment Market Association (SEMA), Massachusetts is among the most restrictive states in this respect, as the state has a law on the books that prohibits the use of exhaust-system components that increase sound output, and every year a law is introduced (and fortunately killed) that would prohibit the installation of any aftermarket exhaust components.

Even where the state restrictions aren’t as tight and you’ve installed an exhaust that’s fully legal, you can still get cited for an aftermarket exhaust. It’s really dependent on enforcement and at the officer’s discretion, said McDonald, who noted that some states rely on officers to judge whether an exhaust is significantly louder than stock (which means that they’re supposed to know how loud a particular model usually is). Others, like California, now rely a test-station system where decibels are objectively measured.

As if that’s not enough, even if you’re legal on the state level, some communities might essentially have rules stating that if there are multiple noise complaints, an owner/vehicle will be cited.

Under the tighter new emissions-check system employed by the state of California, if you’ve recently replaced your catalytic converter -- especially in another state -- with one that’s not official original equipment (OE), you might not be legal in the Golden State. Check CARB’s Web site to make sure that you are. If you have an aftermarket catalytic converter that was installed before January 1, 2009 and is otherwise functioning, you should be okay.

It’s a common and inexpensive modification, especially on four-cylinder import cars and muscle cars; cold-air intakes reach farther away from the engine, even above the hood, for colder intake air and allow the engine in some cases to produce more power. The unfortunate result of a cold-air intake, often, is increased fuel consumption and increased emissions, so even if you think the engine is running better you might be illegal and exceed emissions limits. California’s Air Resource Board (CARB) keeps a database of intakes, among other parts, that don’t appreciably alter emissions, and a number of other states, including Oregon, are beginning to follow CARB’s list. Make sure yours is on the list or you might not pass your next inspection.

You might be able to get a very functional, reliable, and sophisticated aftermarket installation of modern high-intensity discharge (HID) headlamps, but no matter how perfect, they’re not legal -- anywhere in the U.S. Even if you can adjust your added-on HID lamps to federal photometric standards, the National Highway Traffic Safety Administration (NHTSA) has determined that no HID headlamp can comply with the federal standard. Be forewarned, if you have a model that doesn’t typically have HID headlamps, you’ll get a ticket in most states.

Adding a few blue lights underneath your car to add a nighttime ‘aura’ might seem a harmless modification -- but you could quite easily end up with a setup that advertises itself, brightly, as street-illegal. According to SEMA’s McDonald, states still aren’t in agreement on which types of lighting -- neon or LED -- or even which colors, to allow. Technically any lighting that doesn’t interfere with the front and rear lighting required by the federal government is legal, but states have gone further by restricting certain colors and combinations that could be distracting, or misunderstood with traffic lights or emergency vehicles. Blue might be perfectly legal in one state and not another.

These powerful lights, often 100 watts or more each, are sometimes mounted in a bar on the roof or around the grille of a vehicle. Because of their high intensity, diffused light pattern, and long range, these beams can be dangerous to oncoming road traffic. You might have known that, but you might not have realized that in some states, if you don’t keep off-road lamps physically covered when you’re not off-roading, they’re technically illegal. Yes, even when they’re turned off.

Studded tires carry the federal government’s DOT rating and are great for getting a better grip on slippery winter roads -- especially where steep hills and ice render all-season tires and some standard winter treads inadequate. And for most modern studded tires, the metal studs embedded in the tread are much quieter than previous designs. But they also wreak havoc on pavement surfaces. “There are states that allow studded tires, and those that don’t,” summed Matt Edmonds, vice president of the Tire Rack, most of them in the Rocky Mountain region and West. “But even those that do have a specific time period.”

The plastic or metal frames that hold your license plate in place, keep it from rattling, and possibly advertise your dealership might be illegal in some states. Arizona just last year introduced new requirements -- partly because of the number of state-issued custom and vanity plates -- that specified that “Arizona” must be showing, not covered up by a top section of the frame. As for those tinted or reflective license-plate covers: they’re illegal in most states.

Most states (Wyoming is one exception we could find) place a limit on how high you can raise a vehicle -- whether it be through frame-and-body alterations or suspension modifications. Again here, it’s very confusing; some states have maximum headlight and taillight heights to meet, while others go by maximum bumper heights instead. For example, Rhode Island restricts light-vehicle truck or car owners from raising their vehicle more than four inches -- making the hardcore off-road look for trucks virtually impossible -- while Wyoming has no measurable limit. If you’re moving state to state in the wrong direction, your truck (or car) could quickly be illegal. This is one where you should consult your state’s DMV or DOT Web site.

Oddly, there are no federal regulations, and few state rules, that control what size wheels and tires you can put on a vehicle. Whether it be a low-riding off-road vehicle running dubs, or a sedan that’s been raised several feet with huge, skinny wheels, it’s your prerogative. “There really are no regulations ... unfortunately,” lamented Tire Rack’s Edmonds, pointing only to lift restrictions.

With respect to outrageous tires and wheels, it’s up to the owner to make sure that they’re fully compatible and it meets the load-carrying capacity for the vehicle. It’s a question that you’ll need to address with an expert when upgrading, but it’s nothing that you might be cited for.

Well ... perhaps by the style police.

Thanks To:

Specialty Equipment Marketers Association (SEMA), Summit Racing Equipment, MagnaFlow, RaceInspired, Tire Rack and RalliTEK