Bob from Colorado Springs writes, “What’s driving you crazy? Hello Jayson. Maybe you could help shed some light on an issue I've had for many years. Why do drivers operate their vehicles with FOG lights on? I remember when two headlights were enough...now more and more drivers are using fog lights all the time. Fog lights are supposed to be dimmed, just like high beams, when approaching other vehicles...but no one does.”
You are correct Bob, drivers are not supposed to have their fog lights on at night if there isn’t any fog to drive through, but as you see every night, people do it anyway. Why? Most told me, “Why not?” I took a very non-scientific survey of drivers in the pickup line at my daughter’s school, asking if they drive with their fog lights on. The most popular answer of the people who said yes was “So I can see better.” Many admitted to me they think the additional lights makes their vehicle look better. One woman said she didn’t realize she wasn’t supposed to use them all the time and said she would turn them off. Keep in mind that these answers were coming from drivers who, some of which, didn’t have front license plates or had expired tags so conforming to the law didn’t seem like a concern for them.
The common problem caused by these fog lights for other drivers is the lights are annoying and can in some instances, blind on-coming drivers. According to the Colorado Division of Motor Vehicles, if you are driving with your high beam lights on or your low beam lights with fog lights on, you must dim them before coming within 500 feet of any oncoming vehicle so the oncoming driver is not blinded by the glare. They add that when following another vehicle, you must use your low beam lights, with your fog lights off, if you are within 200 feet of the vehicle ahead of you.
The state of Colorado also requires that vehicles do not have more than four front lamps on at any time when on a highway, and the brightness of any lamp on the front of a vehicle not exceed 300 candlepower or 3,770 lumens. That would be similar to the light output of a 250-watt LED bulb. The distribution of light that bright is so intense, it can reveal a person and vehicle at at least 350 feet ahead, according to the state.
The state also has specific requirements when operating fog lights. State statutes dictate a driver cannot add more than two fog lamps mounted on the front of their vehicle between 12-30 inches above the ground. Adjust the lights so the top of the projected fog beam pattern from 25 feet away is about 4 inches down from the light's center when the fog lamps face straight forward.
If someone uses their fog lights incorrectly or illegally and that causes an accident, the at-fault driver can be held responsible for the crash, according to Colorado’s Fang Law Firm. This means that his or her car insurance will have to pay for victims’ medical bills and property repairs. They said common headlight errors include driving at night without headlights, driving with broken or faulty headlights, using excessively bright or custom headlights, and driving with the high beams regardless of other motorists approaching.
As for how to drive in the fog, Les Schwab has a good article that goes through many of the best practices.
Denver7 Traffic Expert Jayson Luber says he has been covering Denver-metro traffic since Ben-Hur was driving a chariot. (We believe the actual number is over 25 years.) He's obsessed with letting viewers know what's happening on their drive and the best way to avoid the problems that spring up. Follow him on Facebook,Twitter or Instagram or listen to his Driving You Crazy podcast on any podcast app including iTunes, iHeartRadio, Spotify and Podbean.