mihtiander / iStock Did you know that you could save money and increase your fuel economy by up to 47 percent, simply by adjusting your driving habits? Do you know what happens when you use a different grade of motor oil than the one recommended by your car’s manufacturer? Take our quiz to see how much you know about fuel economy, fuel efficiency and sustainable driving. START THE QUIZ Question 1 of 7 Score: 0 parisvas / iStock At what speed does gas mileage begin to rapidly decrease? Although every vehicle reaches optimal fuel economy at a different speed, once that baby hits 50 MPH, your gas mileage usually decreases rapidly. For each 5 MPH you drive over 50 MPH, you will be paying an approximate $0.15 extra per gallon for gas. 50 MPH 60 MPH 70 MPH 88 MPH NEXT QUESTION Question 2 of 7 Score: 0 kieferpix / iStock True or False: Aggressive driving not only makes you look like a jerk, it wastes gas. Speeding, accelerating and braking hard can deplete fuel efficiency by a whopping 33 percent on the highway and by 5 percent around town. We won’t even mention the health-risks related to stress. True False NEXT QUESTION Question 3 of 7 Score: 0 Jamesbowyer / iStock What happens when a car idles more than 30 seconds? According to the EPA, when a car idles for more than 30 seconds, it has several negative effects, such as increasing air pollution unnecessarily, wasting fuel and money, and causing excessive wear or even damaging a car’s engine components, including cylinders, spark plugs, and the exhaust system. It wastes fuel It causes excessive wear It increases air pollution All of the above NEXT QUESTION Question 4 of 7 Score: 0 Antonio_Diaz / iStock What are the possible savings associated with telecommuting? According to a study by Telework Exchange, a company focused on demonstrating the value of mobility and telework, around 9.7 billion gallons of gas and $38.2 billion can be saved each year, if only 53 percent of all white-collar workers telecommuted just two days per week. $38 million $380 million $38 billion $38 trillion NEXT QUESTION Question 5 of 7 Score: 0 KrivosheevV / iStock True or False: Extra weight causes a decrease in your fuel economy. For every extra 100 pounds your car carries, your fuel economy is decreased by 2 percent. Worse than that, having a bike rack on top can cause your fuel economy to plummet by more than a third. True False NEXT QUESTION Question 6 of 7 Score: 0 BartekSzewczyk / iStock Why do properly inflated tires improve fuel efficiency? Properly inflated tires have less contact with the road, which means they encounter less friction and your engine doesn’t have to work as hard. You can improve your gas mileage by more than 3 percent by keeping your tires inflated to the proper pressure. Under-inflated tires, on the other hand, can lower gas mileage by 0.3% for every 1 psi drop in pressure. They cause the vehicle to sit higher They encounter less friction They help the vehicle move faster They look good NEXT QUESTION Question 7 of 7 Score: 0 LeventKonuk / iStock True or False: Using a different grade of motor oil than what your car’s manufacturer recommends can lower your gas mileage. Even though a car will run on different grades of oil, using different motor oil than recommended can lower your gasoline mileage by 1 to 2 percent. While we’re on the topic of maintenance, you also want to make sure to get regular tune-ups and maintenance checks to avoid fuel economy issues due to things such as low fluids, worn spark plugs and to replace any worn filters. True False GET YOUR SCORE You scored out of 7 Share this quiz mihtiander / iStock Share this quiz TRY AGAIN Try your knowledge on these other quizzes. Can You Name The Greenest U.S. Cities? Are you poised to master your resolutions? The Earth's mountains, rocks and water bodies are ancient. Do you know how old they are?