According to data compiled from the National Oceanographic and Atmospheric Administration (NOAA) and the U.S Department of Energy by Eric Vandernoot, Astronomy & Physics Lab Coordinator at Florida Atlantic University's Boca Raton campus, the combustion of gasoline in the United States was the cause of 4.4 percent of the carbon dioxide increase in Earth's atmosphere during the year 2005. This data, combined with the obvious effects of carbon dioxide on global climates, makes it clear that car owners and drivers must take steps to reduce the carbon output of their machines. In this article, I will explain how you can conserve resources and save the environment while you drive.

Selecting your Gas Sipper

If it's time for a new car, the choice you make will have a profound affect on the time and money you spend at the gas station. Automobile manufacturers have been designing cars that can achieve more than 80 miles per gallon for European markets for decades. As rising gasoline prices are causing Americans to demand more efficient cars, automobile manufactures are attempting to meet that demand with advanced engines and hybrid propulsion systems.

The first gasoline-electric hybrid automobile sold in the United States was the 1999 Honda Insight, which can drive more than 70 miles per gallon if driven properly (This is not just based on the EPA estimates. My Honda Insight gets 70.5 miles per gallon ON AVERAGE. The best trip I ever made achieved 95.4 miles per gallon!). The Honda Insight only seats two people, but there are other hybrids available. The two most popular and fuel-efficient are the Honda Civic Hybrid and the Toyota Prius, and both seat four people comfortably. You can read more about hybrids at www.bocaraton/hybrids.

On the other hand, real world tests have shown that one can achieve better gas mileage driving a small gasoline or diesel powered car than by driving a Toyota Prius hybrid, and conventionally powered cars are a lot cheaper. Also, there is some speculation that the production and recycling of the batteries required by hybrid vehicles may outweigh the fuel-saving benefits of some hybrids. While Volkswagen refuses to sell their most fuel efficient cars such as the Volkswagen Lupo and the new Volkswagen Fox in the United States, they will begin producing the diesel-powered Volkswagen Jetta in the fall of 2008, which may be able to achieve more than 40 miles per gallon on the highway. The new Honda Fit may be a good choice as well, as Honda uses advanced fuel-saving technology such as Variable Valve Timing and Lift Electronic Control in many of its engines.

Of course, your actual mileage will vary from the EPA estimates, and recent studies have shown that they aren't even that accurate. Perhaps common sense is more reliable than the EPA when choosing an efficient car. Generally, if fuel efficiency is really what you want, look for cars that are smaller, less powerful, and have a manual transmission. Smaller cars require less energy to accelerate, are more aerodynamic, and experience less rolling resistance. A smaller engine means that less gasoline is required to fill the cylinders, the engine weighs less, and less energy is needed to get the engine turning. Finally, and perhaps most importantly, look for cars that have a manual transmission. Automatic transmissions can never be as efficient as manual transmissions because of the necessity of a torque converter in automatic transmissions. In automatic transmissions, the transmission can never spin at the same speed as the engine, and that difference in speed is a waste of energy. (On a side note, automobiles with manual transmission are also safer on slippery driving surfaces, can transfer more power from the engine to the wheels, and give the driver more control over the vehicle).

Efficient Driving Techniques

The most important fuel-saving device in any vehicle is its driver. As an environmentally-conscious driver, it is up to you to operate your vehicle in a manner that squeezes every joule of power from the gasoline in the tank.

The easiest and most effective way to save gasoline is to slow down. A faster moving car accelerates air molecules ahead of it to a higher velocity in moving them out of the way, which wastes more energy. For most cars, the most fuel-efficient speed is the lowest speed the car should drive in its highest gear-usually around 40 miles per hour. The further you get from this optimum speed, the more energy you are wasting. On most parts of 1-95 in South Florida, it is perfectly safe to drive at 55 miles per hour (and it's actually illegal to drive faster than that on some parts. It's strange that people complain about gas prices are willing to break the law to waste gas). Slowing down from 70 miles per hour to 55 miles per hour can actually increase your gas mileage by about 20 miles per gallon. In fact, my Honda Insight can achieve 100 miles per gallon going 55 miles per hour if there's no headwind.

The second most effective way to save gas is to turn off the air conditioner. This may be hard to do at first, but with the fan on and the windows open it's actually quite comfortable, even during the summer time in Florida. I might just be used to the heat, but I'm also used to filling up my 10.6 gallon gas tank about once per month and getting 70 miles per gallon (on average). At highway speeds, increased drag from the open windows does become a factor, but it does not approach the load placed on the engine by running the air conditioner. Actually, I drive on the highway with the windows up and the fan on, but you may need to get used to driving with the windows down before you try that. And make sure you have plenty water to drink.

With both manual and automatic transmission vehicles, a key to efficient driving is keeping the vehicle in as high a gear as possible. In vehicles with automatic transmissions, this means applying little pressure on the gas peddle to prevent the transmission from switching to the lowest possible gear to facilitate your apparent desire to accelerate quickly. For those of you with manual transmission cars, it actually may be more efficient to use full-throttle acceleration, and to shift up as soon as possible to keep the engine speed and acceleration low. By accelerating this way, you spend less time in the high-friction lower gears. Also, less energy is lost accelerating air past a fully-open throttle plate. This technique is a bit difficult to master, as it requires that you shift up very quickly, but you will save some gas.

Another fuel-saving technique that can be utilized by drivers of cars with manual transmissions is to take advantage of the fuel flow cutoff feature present in many of those cars. When your car is slowing down, if you keep the engine rpm higher than the engine idle speed, then it is not necessary for the car to use gasoline to keep the engine running. It is a bad idea to shift the car into neutral while decelerating because the car must use gas to keep the engine idling.

There are reasons I get 70 miles per gallon, while my brother who drives the same car as me gets only 51.4 miles per gallon (after all, it's still a Honda Insight). I hope that this advice will put you on your way to saving money and keeping the air clean. Of course, you will want to start tracking your gasoline usage and mileage so you can see what effect various techniques have on your miles per gallon. Good luck!

If you have questions or comments about this article, please send them to Green@BocaRaton.com. Your comments, along with a response, may be included at the end of this article.