Auxiliary lights are legal in most places, but “legal” depends on three things: the standard the light meets, how you wire it, and how you use it. A light that is perfectly legal as a high-beam supplement becomes illegal the moment you leave it on in oncoming traffic. Here are the actual rules, the actual numbers, and the actual decisions you need to make.
Auxiliary lights are legal for on-road use if they meet SAE J581 in the US or ECE R148/R149 in Europe and other ECE markets, are wired to only activate with high beams or a separate switch, and are aimed correctly. Off-road-only lights with no standard marking are illegal on public roads. Blue and red auxiliary lights are restricted to emergency vehicles in almost every jurisdiction.
The Quick Answer: When Are Auxiliary Lights Legal?
Auxiliary lights are legal for on-road use when all three conditions are met:
- The light meets a recognized standard. In the US, that means SAE J581 for auxiliary driving lamps. In Europe and many other markets, that means ECE R148 or R149 approval with an E-Mark. A light with no standard marking is off-road only.
- The wiring forces correct use. Many states require auxiliary driving lamps to be wired so they can only come on when high beams are on, with a separate switch to turn them off while high beams stay on. Some require a switch separate from the headlight switch.
- You use them correctly. You dim or extinguish auxiliary driving lights when approaching other vehicles. Illinois law, for example, requires drivers to extinguish all auxiliary driving lamps within 500 feet of an oncoming vehicle and within 300 feet of a vehicle ahead.
If a light has no SAE or ECE marking, treat it as off-road only. That is not a guess. No federal certification process exists for auxiliary driving lamps used solely as auxiliary lamps in the US. State law governs their use, and most states adopt SAE J581 as the benchmark.
The one thing most buyers get wrong: they buy a light that says “off-road use only,” mount it on a daily driver, and assume nobody will notice. You will fail a state inspection in states that check auxiliary lamps, and you can be ticketed in states that enforce lighting equipment rules. Buy the right standard from the start.
Two Questions That Decide Everything
Before you buy or install any auxiliary light, answer these two questions. They determine whether your setup is legal in 90% of jurisdictions.
Question 1: Does the light carry SAE J581, DOT, or E-Mark?
SAE J581 is the Society of Automotive Engineers standard for auxiliary upper beam lamps. It defines beam pattern, color, and intensity for lights meant to supplement high beams. A light that meets SAE J581 is designed for the same purpose as your high beams: use when no oncoming traffic, dim when traffic appears.
DOT compliance is a different thing. To be a legal replacement for a required lamp, like a headlight, a light must meet FMVSS 108. Auxiliary lights are not required lamps, so they do not need FMVSS 108 certification. But they still need to meet SAE J581 if your state adopts that standard.
In Europe, ECE R148 covers light-signalling devices, and ECE R149 covers road illumination devices. A light with an E-Mark and R148 or R149 approval is road-legal in ECE member countries.
The judgment: if the product page does not list SAE J581, DOT, E-Mark, or ECE R148/R149, assume it is off-road only. Do not install it on a vehicle you drive on public roads.
Question 2: How is the light wired?
Wiring is where most legal setups fail. Several states require auxiliary driving lamps to be wired so they can only activate when high beams are on. The light must also have a separate switch so the driver can turn off the auxiliary lamps while keeping high beams on.
This wiring requirement exists for a reason: it forces the auxiliary light to behave like a high beam. You cannot run it as a standalone always-on light. If your auxiliary lights come on with the parking lights or with a dash switch that works independently of the headlights, your setup may be illegal in states with this rule.
The judgment: wire your auxiliary driving lights through a relay triggered by the high-beam circuit. Add a separate switch to override. This satisfies the wiring requirement in states like Oregon, New Jersey, and Washington.
US Federal Rules: SAE J581 and FMVSS 108
The US does not have a single federal law that says auxiliary lights are legal or illegal. Instead, the rules work in two layers: federal standards that define performance, and state laws that govern use.
What FMVSS 108 Does
FMVSS 108 is the federal standard for vehicle lighting. It covers required lamps, reflective devices, and associated equipment. It does not regulate auxiliary driving lamps as a required function. Commercial motor vehicles regulated by FMCSA must meet FMVSS 108 for required lamps and SAE J581 for auxiliary driving lamps.
NHTSA does not “approve” lighting products. The DOT mark is the manufacturer’s certification that the equipment meets applicable federal requirements.
What SAE J581 Covers
SAE J581 is the standard for auxiliary upper beam lamps. It specifies beam pattern, color, white, intensity, and aiming. A light that meets SAE J581 is intended to supplement high beams, not replace them. Washington state law, for example, requires auxiliary driving lamps to meet SAE J581, be white, provide forward illumination, and be wired so they only operate with high beams.
What you should look for on a product page: the words “SAE J581 compliant” or “meets SAE J581.” If the page says “off-road use only” or lists no standard, treat it as off-road only.
State Rules: Number, Height, and Switch
State laws vary, but most follow the same pattern: a maximum number of auxiliary driving lamps, a mounting height range, and a wiring requirement. Here are concrete examples.
| State | Max number | Height range | Wiring / use rule |
|---|---|---|---|
| California | 2 auxiliary driving lamps | 16 to 42 inches | Must meet mounting and aiming specs in Title 13 CCR |
| Washington | 2 auxiliary driving lamps | 16 to 42 inches | Must meet SAE J581, be white, wired to only operate with high beams |
| Oregon | 2 auxiliary driving lamps | 16 to 42 inches | Wired so they only come on with high beams; separate switch required |
| Illinois | 3 auxiliary driving lamps | 12 to 42 inches | Must extinguish within 500 ft of oncoming vehicle, 300 ft of vehicle ahead |
| Iowa | 3 auxiliary driving lamps | 12 to 42 inches | Standard auxiliary lamp restrictions apply |
| New Jersey | 2 auxiliary driving lamps | Standard height rules apply | Must be controlled by a switch separate from the headlight switch |
| Texas | 2 driving lamps | Standard height rules apply | Limited to 4 simultaneously illuminated lamps if beam intensity exceeds 300 cp |
How to read this table: the pattern is consistent. Most states allow 2 auxiliary driving lamps, mounted between 16 and 42 inches, wired to high beams with a separate switch. Some allow 3. The 42-inch ceiling is the most common upper limit, because above 42 inches the light can glare into other drivers’ mirrors and windshields.
Your action: look up your state’s vehicle code under “auxiliary driving lamps” or “additional permissible lights.” The three numbers you need are: maximum count, height range, and wiring rule.
Motorcycle Auxiliary Light Rules
Motorcycles have separate auxiliary light rules in many states, and those rules are often more permissive than car rules. The reason is safety: motorcycle auxiliary lights are used to make the bike more visible, not just to see farther.
What Many States Allow
Several states explicitly permit LED pods and strips as motorcycle auxiliary lighting. West Virginia allows amber and white illumination, standard bulb running lights, or LED pods and strips. Illinois allows standard bulb running lights or LED pods and strips as auxiliary lighting with the intent of protecting the driver. Virginia allows standard bulb running lights or LED pods or strips as auxiliary lighting on motorcycles and autocycles.
Some states restrict motorcycle auxiliary lights to red or amber only. Virginia’s inspection rules, for example, reject auxiliary lights that are any color other than red or amber, are not directed toward the ground, or project more than 25 candlepower per bulb.
What This Means for You
If you ride a motorcycle and want to add auxiliary lights for visibility, white or amber LED pods aimed low and wide are the safest legal choice in most states. Avoid blue and red. Avoid any light that projects a beam straight ahead at eye level of other drivers.
The judgment: motorcycle auxiliary lights are generally treated as conspicuity lighting, not driving lighting. That means the legal test is different: can other drivers see you without being blinded? Low-mounted amber or white pods pass that test. High-mounted white spots aimed at eye level do not.
For LOYO motorcycle-specific options, see our Motorcycle Auxiliary Lights collection. Our 4-inch combo beam pod is E-Mark certified for on-road use in ECE markets.
Europe: ECE R148 and E-Mark
In Europe, the legal framework is different from the US. Instead of SAE standards, the relevant rules are UN Regulations (ECE). ECE R148 covers light-signalling devices. ECE R149 covers road illumination devices. A light with an E-Mark and approval under R148 or R149 is road-legal in ECE member countries.
ECE R148 approval means the lamp has been type-approved as a light-signalling device, typically for position light functions. ECE R149 approval covers the illumination function, such as a driving beam. A road-legal European auxiliary driving light usually carries both: R149 for the driving beam, and R148 for the integrated position light if it has one.
What you should look for: an E-Mark with the regulation number. The marking typically looks like “E1 148R00/06” or “E1 149R00.” If the product page says “E-approved” but does not list the regulation number, ask for it. “E-approved” alone is not enough detail to confirm road legality.
Mounting and Wiring in Europe
European rules also specify mounting position and wiring. Auxiliary driving lights must be mounted symmetrically and at a height that does not cause glare. Some European vehicles use CAN bus or vehicle control systems to manage auxiliary light activation, and the wiring must integrate correctly with those systems. If the installation does not comply with the permitted mounting position, the light is not legal even if it carries E-Mark approval.
India, UK, and Other Markets
India
India’s rules are strict. Rule 104 of the Central Motor Vehicles Rules requires all lighting to conform to prescribed brightness and beam pattern standards. Any lighting that does not conform is illegal. Rule 100(2) restricts the use of blue, red, flashing, and strobe lights to authorized emergency vehicles. Spotlights and search lights are prohibited on the front of vehicles except with prior approval from the registering authority.
Enforcement has tightened. Kerala’s High Court directed the Transport Department to act against modified vehicles with illegal auxiliary lights, including strobe lights. In 2026, authorities in Bangalore conducted a crackdown on unauthorized LED headlights, colored flashlights, and modified auxiliary lights on two-wheelers, cars, and goods vehicles.
The judgment for India: do not install auxiliary lights on a vehicle used on public roads unless you have confirmed compliance with Rule 104 and have the necessary approval. The enforcement risk is real and increasing.
United Kingdom
The UK follows ECE regulations for vehicle lighting. Auxiliary driving lights must carry E-Mark approval and meet mounting and use requirements. The Road Vehicles Lighting Regulations 1989 govern when auxiliary lights can be used. As in Europe, E-Mark approval with the correct regulation number is the benchmark.
Other Markets
Most countries that follow UN vehicle regulations accept ECE R148 and R149 approval. That includes much of Europe, the UK, Australia, New Zealand, and many countries in Asia and Africa. If you export or drive across borders, E-Mark approval is the most widely recognized mark. SAE J581 is recognized primarily in the US and Canada.
Color Rules: What You Cannot Use
Color is the easiest way to get stopped. The rules are consistent across most jurisdictions: white and amber are allowed for forward-facing auxiliary lights. Blue and red are restricted to emergency vehicles.
| Position | Allowed colors | Restricted colors | Notes |
|---|---|---|---|
| Front auxiliary lights | White, amber | Blue, red | Blue and red reserved for emergency vehicles in most jurisdictions |
| Rear auxiliary lights | Red, amber | Blue, white (forward-facing) | Rear lights must not show white toward the front |
| Motorcycle accent lighting | Amber, white, red (braking only) | Blue | Some states allow red only when brake is applied |
| Off-road only | Any | N/A | Off-road use only; not legal on public roads |
Maine law is a good example of how specific the color rules can be: white or amber on the front, amber or red on the rear. Blue interior auxiliary lighting is allowed only if no portion of the beam is visible at 42 inches above the ground at 20 feet from the vehicle.
The judgment: white for forward visibility. Amber for fog, dust, and snow. Red for rear-facing brake or marker functions. Never blue. Never flashing red or blue unless you are an authorized emergency vehicle.
How to Build a Legal Setup: A Checklist
Here is the direct version. Follow these steps and your auxiliary light setup will be legal in most jurisdictions.
- Buy lights with the right standard. SAE J581 for US on-road use. ECE R148 and R149 with E-Mark for Europe and other ECE markets. If the product has neither, treat it as off-road only.
- Mount within the legal height range. Most states allow 16 to 42 inches for auxiliary driving lamps. Fog lamps typically mount 12 to 30 inches. Check your state’s specific range.
- Wire through a relay triggered by high beams. The auxiliary lights should only be able to activate when high beams are on. Add a separate switch so you can turn them off while high beams stay on.
- Aim them correctly. Auxiliary driving lights should be aimed to supplement high beams, not to illuminate the sky or oncoming drivers’ eyes. Poor aiming is the most common cause of glare complaints and tickets.
- Use them correctly. Dim or extinguish auxiliary driving lights when approaching other vehicles. Illinois requires extinguishing within 500 feet of oncoming traffic and 300 feet of a vehicle ahead. Other states have similar rules.
- Keep the color legal. White or amber front. Red or amber rear. No blue. No flashing red or blue.
- Check your state’s maximum count. Most states allow 2 auxiliary driving lamps. Some allow 3. Do not exceed the limit.
If you only remember one thing: SAE J581 or E-Mark on the box, high-beam-triggered wiring, correct aiming, and correct use. Those four things make an auxiliary light setup legal in the vast majority of jurisdictions. Skip any one of them and you are taking a risk.
For step-by-step wiring instructions, including high-beam trigger wiring, see our guide: How to Install and Wire Auxiliary Lights.
Auxiliary Light Legal FAQ
Are auxiliary lights legal on cars?
Yes, if they meet SAE J581 in the US or ECE R148/R149 in Europe, are mounted within the legal height range, wired to only activate with high beams or a separate switch, and used correctly. Off-road-only lights with no standard marking are illegal on public roads.
How many auxiliary lights can I legally install?
Most US states allow 2 auxiliary driving lamps. Some states, like Illinois and Iowa, allow up to 3. Check your state’s vehicle code for the exact limit. Going over the limit can fail a state inspection or result in a ticket.
Can I use auxiliary lights as my main headlights?
No. Auxiliary lights are not designed to meet headlight standards for beam pattern, cutoff, and switching. Using them as headlights is illegal in most places and dangerous because they glare oncoming traffic. They supplement headlights; they do not replace them.
Are blue auxiliary lights legal?
No, in almost every jurisdiction. Blue lights are reserved for emergency vehicles. Red lights are also restricted to emergency vehicles in most places, though some states allow red for rear-facing brake or marker functions. Stick to white and amber for forward-facing auxiliary lights.
Do auxiliary lights need to be covered on public roads?
Some states require off-road-only auxiliary lights to be covered when the vehicle is on public roads. This is more common for large light bars and off-road-only spot lights. If your lights carry SAE J581 or E-Mark approval, covering is generally not required, but check your state’s rules.
What happens if I get caught with illegal auxiliary lights?
Consequences vary by jurisdiction. You may receive a fix-it ticket requiring you to remove or correct the lights, a fine, or a failed state inspection. In some jurisdictions, repeated offenses can lead to more serious penalties. The simplest approach is to install legal lights correctly from the start.
Are auxiliary lights legal in India?
India’s Central Motor Vehicles Rules require all lighting to conform to prescribed brightness and beam pattern standards under Rule 104. Blue, red, flashing, and strobe lights are restricted to emergency vehicles. Enforcement against illegal auxiliary lights has increased in recent years. Confirm compliance before installing on a road vehicle.
What is the difference between SAE J581 and ECE R148?
SAE J581 is the US standard for auxiliary upper beam lamps. ECE R148 is the UN regulation for light-signalling devices, used in Europe and many other markets. A light with SAE J581 is designed for US on-road use as a high-beam supplement. A light with ECE R148 or R149 approval is road-legal in ECE member countries. Some lights carry both.