Earth Day: Making greener automotive choices

In the automotive world there are a number of ways to make greener choices. The most notable is to drive a more fuel-efficient car or SUV. Manual transmission vehicles can also save gas and money, although finding models with manual shifts gets tougher everyday--they simply don’t sell in the numbers they used to.

Hybrid vehicles typically deliver the highest fuel economy numbers in their class and there are a number of new models hitting the market, including the new 2010 Toyota Prius, which the company expects to get 51 mpg in the city and 48 mpg on the highway, the Honda Insight, (40 mpg city/43 mpg highway), and the Ford Fusion and Mercury Milan, which both have an EPA estimated 41 mpg city/36 mpg highway. We have not yet run our own real world fuel economy tests in these vehicles to confirm these numbers, however. To see how Consumer Reports tests fuel economy, see our video. Compare fuel economy on all vehicles tested with our new car selector.

Other alternate fuel vehicles racing to the market include plug-in hybrids such as the upcoming Chevrolet Volt and a number of electric vehicles.

Besides buying a new vehicle, how you drive your current car can also help save gas by avoiding unnecessary drag, driving smoothly, and at moderate speeds. Car pooling and taking mass transit are other options.

For more suggestions on how to live more green, visit Consumer Union's Web site Greenerchoices.org and our Earth Day special section. For more tips on saving fuel and alternative fuels, see our Green car guide.

—Liza Barth

Comments

[UH2L]

Some good tips with respect to driving more efficiently. But, a supposedly knowledgeable publication like Consumer Reports should know that manual transmissions don't always get better fuel economy than automatics. EPA ratings sometimes show this. But there's more to it.

At highway speeds, automatics often do better. This is because
the gearing on a manual transmission needs to make the engine rev higher at highway speeds to accommodate the lack of a torque-multiplying torque converter that an automatic has. In the city however, manuals can get better fuel economy because fuel usage goes to zero gets during deceleration and engine braking which automatics don't often do. Also, manuals have less driveline losses because of the direct connection and lack of a torque converter which is a fluid coupling

We need to stop this myth that manuals always get better fuel economy. If you do lots of highway driving, an automatic can do better. If you do lots of city driving and rev it like crazy before upshifting, an automatic can do better. But if you drive efficiently by upshifting early and making use of engine braking in the city, a manual can do much better.

[Jeff Bartlett - Consumer Reports]

True, manual transmissions don't always provide the best fuel economy.

Here is a full report on manuals vs automatics, with a video:
http://www.consumerreports.org/cro/cars/new-cars/news/2008/10/save-gas-and-money-with-a-stick-shift-10-08/overview/manual-vs-auto-ov.htm

[UH2L]

It's good that you ran manuals versus autos and you cover some basic pluses and minuses, but the flaw with your test results is that you have a test loop that is a mix of city and highway which may not be close to what people drive. Based on your table of results, a reader would conclude that manuals are more fuel efficient for all drivers at all times.

Like I said, if you run just highway miles at higher speeds, the automatics will tend to come out ahead, (assuming they have the same number of gears in both automatic and manual). Engine rpm at 60 mph and 70 mph are crucial to determine which transmission is more efficient at highway speeds. In stop-and-go city driving, manuals will come out ahead.

But driving technique is crucial regardless of transmission. I could beat an aggressive manual driver with my automatic because of how I drive. Also, my Saab (and many other vehicles), have an automatic transmission with a manual shift feature and sport mode that keeps the torque converter locked up longer. This can emulate zero fuel engine braking that a manual accomplishes and helps fuel efficiency in the city.

[John]

Making autos more efficient encourages more driving, and thus more consumption of oil, not less. It's the Jevons Paradox.