Washington State Headlight Laws: Requirements, Modifications, and Fines

Washington State headlight laws require every motor vehicle on a public road to have at least two working headlights that produce white light, offer both high and low beams, and meet federal safety standards. You must turn them on from half an hour after sunset until half an hour before sunrise, and any time visibility drops below 1,000 feet. Most violations are traffic infractions with a base fine of $48, but penalties climb quickly if faulty or illegal lighting contributes to a crash.

Required Headlights on Your Vehicle

Every motor vehicle must have at least two headlights, one on each side of the front. The center of each headlight must sit between 24 and 54 inches above the ground.¹

The light itself must be white. Washington ties its lighting rules to Federal Motor Vehicle Safety Standard (FMVSS) No. 108, which governs headlight performance, aiming, durability, and color for every vehicle sold in the United States.²³

Every vehicle must offer both a high beam and a low beam. The high beam must reveal people and vehicles at least 450 feet ahead. The low beam must illuminate at least 150 feet ahead, and none of its high-intensity light may be aimed at the eyes of an oncoming driver.⁴

Bulbs are not the only thing that has to work. RCW 46.37.010 makes it an infraction to drive a vehicle that is not equipped with lamps “in proper working condition and adjustment.” A heavily oxidized, cracked, or moisture-filled housing that cuts your light output falls under that rule even if the bulb technically lights up.⁵

When You Have to Turn Them On

Headlights are required from half an hour after sunset to half an hour before sunrise. They are also required any time weather or other conditions reduce visibility to less than 1,000 feet, which covers fog, heavy rain, snow, and smoke.⁶

Washington does not require standard passenger vehicles to run headlights during daytime driving. Many newer cars have automatic headlights or daytime running lights, but the law does not mandate them, and it is still your responsibility to confirm the lights actually come on when conditions get worse. An officer can cite you regardless of what the automation was supposed to do.

High-Beam Dimming Rules

You must switch from high beams to low beams when an oncoming vehicle is within 500 feet, and when you are following another vehicle within 300 feet. The statute treats the low beam as glare-free regardless of road contour or vehicle load.⁴ The rule applies everywhere, not just on highways.

Modifications That Will Get You Cited

Washington’s rule on aftermarket lighting comes down to one principle: you cannot change a headlight’s original design or performance unless the replacement part has been approved by the Washington State Patrol. RCW 46.37.310 requires that every aftermarket headlamp, fog lamp, rear lamp, signal lamp, or reflector be of an approved type and carry a legible trademark or name showing that approval. Headlamps meeting SAE or applicable United Nations standards are considered lawful.²

HID and LED Conversion Kits

Aftermarket HID and LED bulb kits are a common source of trouble. Dropping an HID or LED bulb into a housing designed for a halogen bulb usually changes the beam pattern and throws glare at oncoming drivers. If the kit does not meet FMVSS 108 and has not been approved by the State Patrol, it violates Washington law.³ Properly designed LED or HID assemblies sold as complete units with matching optics are typically fine if they carry the required approval markings.

Tinted and Smoked Covers

Tinted, smoked, or opaque headlight covers cut light output and change the beam pattern. RCW 46.37.030 prohibits adding any lamp or equipment that “impairs the effectiveness” of required lighting, and RCW 46.37.310 separately bars any modification that changes the original design or performance of a headlamp without State Patrol approval.² A smoked cover that drops your beam distance below the 150-foot low-beam minimum is a citable violation.

Prohibited Colors and Flashing Lights

Blue lights are restricted to law enforcement vehicles and certain fire department vehicles. Red emergency lights are limited to authorized emergency vehicles, law enforcement, emergency tow trucks, and school buses.⁷ Installing blue, red, or green headlight bulbs on a civilian vehicle can lead to a citation for illegal use of emergency equipment.

Flashing or strobing headlights on civilian vehicles are prohibited under RCW 46.37.190, which restricts those warning lights to school buses, private carrier buses, authorized emergency or law enforcement vehicles, and organ transport vehicles.⁸

Fog Lights and Auxiliary Lamps

You may install up to two of each of the following: spot lamps, fog lamps, auxiliary passing lamps, and auxiliary driving lamps.⁹

Fog lamps must be mounted between 12 and 30 inches above the ground and must be aimed so that, with the vehicle unloaded, the high-intensity portion to the left of center projects no higher than 4 inches below the lamp center at 25 feet ahead. They can be white or amber, and they may only be used alongside low-beam headlights, never in place of them.¹⁰

Auxiliary driving lamps must be mounted between 16 and 42 inches from the ground and follow the same dimming rules as headlights: turn them off or switch to low beam when approaching oncoming traffic within 500 feet or following within 300 feet. Neither auxiliary driving lamps nor auxiliary passing lamps can be used alone in place of headlights.⁹

Motorcycle Headlight Rule

Motorcycles and motor-driven cycles face a stricter rule than passenger vehicles: headlights and taillights must be on whenever the motorcycle is moving on a highway, regardless of time of day or visibility.¹¹

Fines and When Things Get Worse

Most headlight violations are traffic infractions, not criminal offenses. The base fine for a general equipment infraction under RCW 46.37.010 is $48. Illegal use of emergency lighting equipment under RCW 46.37.190 carries a higher base penalty of $93.¹² Statutory assessments and local court fees push the total you actually pay above those base figures.

Equipment infractions issued to commercial motor vehicle drivers do not count toward the accumulation threshold that can trigger a license suspension.⁵ For other drivers, Washington does not use a traditional points system, but the Department of Licensing tracks moving violations, and enough tickets within a short period can put your license at risk.

If an officer decides an equipment defect makes your vehicle unsafe, RCW 46.32.060 lets them stop you from driving it until the problem is fixed. The officer may direct you to a repair facility, or impound the vehicle on the spot if the defect is serious.

When Penalties Escalate

If a headlight violation contributes to a crash, the consequences get much worse. A driver whose illegal or missing headlights played a role in a collision could face reckless driving charges under RCW 46.61.500, which requires willful or wanton disregard for safety. Reckless driving is a gross misdemeanor carrying up to 364 days in jail and a fine of up to $5,000.¹³ Civil liability for injuries is a separate exposure on top of any criminal penalty.

Who Is Exempt

RCW 46.37.518 provides exemptions for street rod and custom vehicles registered under special classifications. These vehicles may keep original or modified lighting that would not meet current standards for a daily driver. Collector vehicles are generally restricted to exhibitions, parades, and similar limited use rather than everyday commuting.

Fire department vehicles may use red flashing lights, and in some cases rear-facing blue lights at emergency scenes. Law enforcement vehicles are authorized for both red and blue lights. Firefighters with approval from their department chief may display a green identification light on the front of their private vehicle when responding to an emergency, but that light does not give them any emergency vehicle driving privileges.¹⁴ None of these exemptions extend to civilian vehicles, even those used for similar purposes on private property.

1
Washington State Legislature. Revised Code of Washington 46.37.040 – Head Lamps On Motor Vehicles
2
Washington State Legislature. Washington Code 46.37.310 – Selling or Using Lamps or Equipment
3
eCFR. 49 CFR 571.108 – Standard No. 108; Lamps, Reflective Devices, and Associated Equipment
4
Washington State Legislature. Washington Code 46.37.220 – Multiple-Beam Road-Lighting Equipment
5
Washington State Legislature. Washington Code 46.37.010 – Exemptions and Applicability
6
Washington State Legislature. Washington Code 46.37.020 – When Lighted Lamps and Signaling Devices Are Required
7
Cornell Law School. Washington Admin. Code 204-21-230 – Lighting Equipment Prohibited
8
Washington State Legislature. Washington Code 46.37.190 – Warning Devices on Vehicles
9
Washington State Legislature. Washington Code 46.37.180 – Spot Lamps and Auxiliary Lamps
10
Washington State Patrol. After-Market Vehicle Equipment Brochure
11
Washington State Legislature. Washington Code 46.37.522 – Motorcycles and Motor-Driven Cycles, When Head Lamps and Tail Lamps to Be Lighted
12
Washington State Courts. Monetary Penalty Schedule for Infractions
13
Washington State Legislature. Washington Code 46.61.500 – Reckless Driving, Penalty
14
Washington State Legislature. Washington Code 46.37.185 – Green Light on Firefighters Private Cars