How much extra gasoline would Americans use if daytime running lights were mandatory?

Since the gas price spike in 2008, drivers will do almost anything to increase fuel efficiency. Tips including keeping your tires inflated and turning off your headlights have been suggested to increase gas mileage. Adam Savage and Jamie Hyneman devoted an episode of The Mythbusters to determine whether AC or windows rolled down would save on fuel consumption (if you didn’t see that one, the answer is windows down, believe it or not). With the emergence of more countries requiring the use of daytime running lights (DRLs) which automatically run whenever a vehicle’s ignition is started, you may be concerned about how much more you’ll pay at the pumps if the United States eventually joins the club. How much extra gasoline do you think it takes to run DRLs? 

Why do other countries require DRLs?

Transport Canada claims the mandate for DRLs reduces daytime collisions by 11.3 percent. Detractors debate that DRLs distract oncoming motorists and lessen the visibility of cars without DRLs which could lead to more accidents. It’s still debatable, but, various countries have chosen the route of DRL use for improved road safety. Denmark, Sweden, and others purport the use of DRLs lowers the number of daytime accidents by enhancing visibility.

How DRLs use gasoline

Anything requiring power on or in your vehicle obtains that energy from gasoline. Like any other bulbs, you have options for different wattages for your car lights from 160 watts halogen lights to 16 watt LED lamps. The lower the wattage, the less drain on your gas tank. The development of higher efficiency lamps (more lumens per watt) and emerging LED technologies will use less gasoline while providing the safety feature of enhanced visibility.

Brass Tax: How much will it cost to implement the use of DRLs?

The United States National Highway Transportation Safety Administration claims DRLs decrease fuel efficiency by a "fraction of a mile per gallon." A few assumptions must be made to estimate gas consumption for DRLs. Of the 244 million cars on the road, assume the wattage of DRLs averages to 90 watts and the average gas mileage is approximately 20.3 miles per gallon. Approximately 70% of the 7 billion miles driven by Americans daily are driven during daytime hours (about 4.9 million miles). With these numbers in mind, Americans currently use approximately 241.4 millions gallons of gas during daylight hours. Factor in an estimated 1% reduction in fuel efficiency for running DRLs and that number increases to 243.9 millions gallons of gasoline. If gas prices spike again to the costs from August 2008, at $3.81 per gallon, more than an extra $7.62 million would be spent on gasoline in America every day. When the $7.62 million is divided by the number of cars on the road, the cost of the 1% reduction of fuel efficiency from factors like DRLs doesn’t amount to a whole penny per vehicle.

Cost versus safety

If an argument against a mandate for DRLs in the United States is going to be effective, fuel efficiency won’t make much of a case. Especially when one considers the energy saving possibilities of LED lights, more studies will be required to verify the safety improvements or lack thereof when using DRLs. If you’re still worried about gas, roll your windows down.