The folks at Automatic, an app that pairs with hardware connected your car's computer to produce personalized data such as real-world fuel economy, recently examined just how much aggressive driving can cost by analyzing the habits of one of its own employees. The data showed that the employee was getting just a fraction of their car's -- a BMW 328i -- potential city fuel economy when accelerating 7+ mph per second (which roughly translates into a nine-second 0-60 mph sprint).
Any kind of acceleration, fast or slow, requires more fuel than maintaining a speed or slowing down. When you stomp on the gas pedal, more fuel enters the engine and RPMs spike, giving you a surge of power. This gets you to your cruising speed quicker, but at a heavy penalty.
Accelerating at a smoother, slower rate will get you to speed a little more slowly, but it can save you a lot of gas. In the case of the Automatic employee, accelerating at 7+ mph per second meant their car was operating at a fuel efficiency of under 3 mpg. Had they accelerated at around 4 mph per second, they would have been operating at close to 8 mpg. Driving in an urban area with a lot of stop-and-go traffic meant that the employee's ordinarily decently fuel efficient 328i became a veritable gas guzzler.
If you're finding that your car isn't achieving the fuel economy you think it should, step back and take a look at how hard you're accelerating. Flooring the gas pedal is a hoot, but laying off the gas even slightly can reap some big financial benefits.
Head on over to Automatic for the entire study.