Rules of the Road: When during the day must headlights be on?


Questions: I commute on the Mount Baker Highway and oftentimes three out of four people are not using their headlights when legally required to (raining, dusk, dawn). This is a problem countywide, but Highways 542 and 547 seem to be particularly affected. Talking to people I have found almost no one even knows the laws.

What laws pertain to using headlights in foggy conditions? Headlights don't help the driver see the road better, but they certainly help us see one another.

It is the time of year when daylight is short. It concerns me to see drivers all over Bellingham not using their headlights during the day when the weather causes makes daylight not bright enough. Can you remind drivers of the laws on this?

Answers: Chapter 46.37 of the Revised Code of Washington covers all things lighting. Here are some of the specifics.

RCW 46.37.020 When lighted lamps and signaling devices are required.

Every vehicle upon a highway within this state at any time from a half hour after sunset to a half hour before sunrise and at any other time when, due to insufficient light or unfavorable atmospheric conditions, persons and vehicles on the highway are not clearly discernible at a distance of 1,000 feet ahead shall display lighted headlights, other lights, and illuminating devices as hereinafter respectively required for different classes of vehicles, subject to exceptions with respect to parked vehicles, and such stop lights, turn signals, and other signaling devices shall be lighted as prescribed for the use of such devices.

So, if we all remember to turn on our headlamps from dusk to dawn, when it is foggy, raining hard, snowing, etc, it makes us all easier to be seen.

Q: The law states that all headlight bulbs are to be white in color. Why can those with blue headlights keep driving with them? What about yellow headlights?

A: This is more problematic than it may seem. The Washington State Patrol is charged with making sure that all of the lights that are used meet certain Federal Motor Safety requirements.All lights that are factory installed will meet these requirements. If you replace your headlamps with the same type, you will continue to be legal.

With the advent of the new headlight technology, the traditional yellowish-white color of headlights is changing. The xenon bulbs have a different "color" than the bulbs used in some of the higher-priced cars. All of them have a different "color" than what we grew up with (at least some of us old folks). The largest problem with any of the lights is having them improperly aimed, especially if a load is placed in a truck or trunk of a car that raises the front of the vehicle.

If you go to purchase aftermarket items for your vehicle, they should be legal for use. If the package says "For Show Purposes Only," they are not legal for use on the street. This includes things such as colored license plate covers, the smoke or black covers that fit over your headlights and taillights (not legal on the street), and even some of the window tints that you can install yourself.

Here are a couple of the appropriate legal sections:

RCW 46.37.180 Spot lamps and auxiliary lamps. This is the section that deals with how many (not more than two), how high or low they can be mounted, and when they are allowed to be used.

RCW 46.37.220 Multiple-beam road-lighting equipment. This section deals with the combinations of lights that are allowed and how they must be aimed.


Rules of the Road is an online forum with questions and answers on road laws, safe driving habits and general police practices. To ask a question, use this form.

David Wright is a retired officer from the Bellingham Police Department who is now on the Whatcom County Traffic Safety Task Force.

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