Wanna know if a car is fuel efficient?

Just how fuel-efficient is your car? One way to get a fair approximation is to zero your trip odometer every time you top off your fuel tank, run the car for awhile, then top off your tank again and divide the number of kilometers traveled by the number of liters put in. Of course, it’s not a very accurate measure since — given the vagaries of fuel pumps, gas boys (and girls), and your own car — not all full tanks are always of the same volume. Over time though, it’s a pretty good method to get the average fuel consumption of your car and your driving style.

For the more fuel-conscious among you, check out www.fueleconomy.com then. It’s the official everything-about-fuel website of the US Department of Energy and the Environmental Protection Agency, the latter of which performs mandated fuel economy, emissions, and crash safety tests on every passenger car, truck, SUV, and pickup truck sold in the US for general consumption.

Containing facts, figures, tips, and side-by-side comparisons, the site is a useful guide for those who want to know how best to save on fuel costs. For example, "Gas mileage decreases rapidly at speeds above 60 mph. Each 5 mph you drive over 60 mph is like paying an additional $0.10 per gallon for gas. Observing the speed limit is also safer."

Those planning to buy a new vehicle and want to know how much you’ll pay at the pump can also check out the car finder section. It features only US-spec vehicles, of course, so don’t take everything at face value if you’re planning to buy locally. For example, a US-spec 2001 Honda CR-V with all-wheel drive, a 4-speed automatic, and a 2.0-liter engine consumes 10.7 L/100 km in the city, 9.4 L/100 km in the highway, and 10.2 L/100 km in combined city/highway driving according to the EPA’s method of measuring fuel economy. That, by the way, means driving at a steady pace over a period of time. Depending on how you drive, you can either get better or worse figures.

How about like-sized, like-priced comparisons then? Surfers can also use the side-by-side function for their Windows-shopping purposes. Comparing the CR-V to the Toyota RAV4 of the same model year and similarly equipped with a 2.0-liter engine, a 4-speed automatic, and all-wheel drive, the RAV4 gives better numbers. City driving is estimated at 10.2 L/100 km, highway driving at 8.7 L/100 km, and combined city/highway at 9.4 L/100 km. GHG emissions are also a little lower at seven metric tons a year, and it rates a six out of 10 on the smog-meter.

What are the best and worst vehicles when it comes to drinking (and passing) gas? Check out the "2002 Most and Least Fuel Efficient Vehicles" page, which uses miles-per-gallon figures. The Honda Insight takes the prize with a 61/68 city/highway MPG figure. Sports car buyers will be happy to know that not only does the Audi TT look good, but it also merits an excellent 23/31 MPG rating. Exoticar enthusiasts will also know that the sizzling hot Lamborghini Murcielago with its 6.2 liter V12 gets a mere 9/13.