General Motors Proves Holiday Decorations Hurt Fuel Economy

Courtesy: Joe Raedle/Getty Images
Courtesy: Joe Raedle/Getty Images /

General Motors’ engineers have just proven that putting holiday decorations on your vehicle can actually hurt its fuel economy and efficiency.

When the holidays roll around, many people want to spread the holiday joy by decorating their houses. But some people also want to decorate their cars, so that they can feel festive everywhere they go. We have all seen those fake reindeer antlers on the sides of a car or the unmistakable Rudolph nose on the grille.

As it turns out, though, these decorations may actually have a negative affect on a vehicle’s fuel economy. General Motors set out to prove this theory with science and concluded that they can be a drag, both literally and figuratively.

To conduct this experiment, General Motors’ engineers tested festive holiday decorations in a wind tunnel. They calculated exactly what the add-ons did to the vehicle’s aerodynamics and fuel efficiency.

The Results:

  • The fake reindeer antlers and Rudolph nose raised the drag coefficient by approximately 3 percent. This, in turn, caused gas mileage to be cut by 1 mpg.
  • The bow on the roof of the car increased drag by 15 percent and caused fuel economy to decrease by 3.5 mpg.
  • A Christmas tree attached to the roof caused drag to go up by 70 percent, which cut fuel mileage by about 30 percent. GM found that the air pushed the tree with around 90 pounds of force; hence, why it is crucial to ensure that it is securely tied before driving home.

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In the video, they first showed how the air flows over the GMC Terrain when it does not have any decorations attached to it. They then demonstrated how wavy that airflow gets with the holiday add-ons. You can see the flow of air go from a smooth stream to one with a messy and uncontrolled direction.

“It might be best to let Rudolph lead Santa’s sleigh instead of your ride this holiday season,” said Joel Ruschman, GM aero performance engineer.

GM advises you to maybe consider just decorating your house, and not your car. If you choose to forgo that advice, just make sure that all the decorations and/or Christmas tree are tightly secured to your vehicle at all times.

Remember, you are looking to spread holiday cheer, not cause holiday anguish with an unfortunate incident.

Next: Tesla’s Christmas Treat Is A Voice-Activated “Santa Mode”

Watch the video below to see how the engineers used aero testing on a 2018  GMC Terrain to prove that decorations can cut gas mileage.

Check out how one guy decorated his green Porsche 718 Cayman S for the holidays below. Watch as he drives the car through Central London with Car Throttle to spread the holiday cheer.

Have you ever decorated your car for the holidays? If so, comment below and let us know or show us some photos. If you haven’t, tell us what you think of the people who choose to decorate their vehicles.