GM Has Scientifically Proven That Holiday Car Decorations Are Bad

Screenshot via GM
Screenshot via GM

Some people decorate for the holidays. A smaller margin go so far as to decorate their vehicles, too. This is inexplicable, and now there is science, courtesy of GM, detailing how inefficient and bad those tacky dollar-store antlers, bows and wreaths can be.


GM’s aerodynamic performance engineers tested various holiday decorations attached to a GMC Terrain in a wind tunnel to measure the impact of these festive additions, with the critical issue being aerodynamic drag, via The Detroit Free Press.

The tests were done at wind speeds equivalent to the vehicle traveling approximately 70 mph, and these were the results, via Freep:

GM found:

•Reindeer antlers and Rudolph’s nose create about a 1-mile-per-gallon decrease in highway fuel efficiency and a 3% increase in drag coefficient — commonly understood as air resistance.

•A roof-mounted bow creates a 3.5-mpg decrease in highway fuel efficiency and a 15% increase in drag coefficient.

•A Christmas tree tied to a roof creates a 30% decrease in highway fuel efficiency and a 70% increase in drag coefficient. Air pushes against a tree with about 90 pounds of force.

•A grille-mounted wreath has no impact on aerodynamics but may reduce cooling airflow to the engine.

“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.


Who knew looking ridiculous came at such a cost? Unfortunately, there was no research on the impact of using real reindeer antlers, or regular deer antlers. I think, ultimately, this is just GM’s engineers and designers subtly trying to get people to stop degrading their work with such mockery. Happy Holidays.

Reviews Editor, Jalopnik

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The decorations are fine, the GM cars are what are bad.