From the mid-1970s to 1990, the average fuel economy for all vehicles on the road in the U.S. doubled from about 14 to 28 miles per gallon (mpg). By 2005, it had dropped to 24 mpg. Driving a fuel-efficient vehicle will save you money on gas, of course, but such a decision has other, broader, effects.
Nature required more than 200 million years to develop all of the oil below the earth's surface. Mankind required just 200 years to consume half that. If current rates of consumption continue, the U.S. Department of Energy says the world's remaining resources of conventional oil would be exhausted in 40 years.
About 60 percent of the oil the world consumes powers transportation vehicles, and half goes to passenger cars and light trucks. It's little surprise that the United States, the world's leading economic engine, also imports and consumes more oil than any other nation.
Whether America's oil consumption is disproportionate is a terrific subject for debate, one we won't engage here. And whether the world has 40 or 140 years of oil left, the reality of the market is this: As oil resources dwindle and oil becomes prohibitively expensive to locate and extract, mankind will replace petroleum as a primary source of power because alternative forms of energy simply will be more economical.
Still, burning less gas in our vehicles will affect the pace at which oil is consumed. In this article, we'll discuss how you can do your part by buying a fuel-efficient car, including how to compare various makes and models. We'll even give you tips on how to evaluate miles per gallon and how to look for air conditioning and other features you want with the best available fuel economy.
Even more important, fuel conservation will impact the demand for oil. And that has meaningful political, technological, and environmental consequences.
Dependence on Imported Oil
Transportation accounts for two-thirds of U.S. petroleum use, and in 2005, America depended on imports for 55 percent of its oil, the highest percentage ever. As domestic resources are used up, that dependence on foreign oil will increase. Some 70 percent of the world's oil reserves are in the Middle East, under control of the OPEC oil cartel.
In the past, the dependence on oil has had a profound effect on the U.S. economy. The Department of Energy calculates that oil-price shocks and price manipulation by the OPEC cartel from 1979 to 2000 cost the U.S. economy about $7 trillion-almost as much as we spent on national defense over the same period, and more than the interest payments on the national debt.
With increasing world dependence on OPEC oil, future price shocks are possible. Each major oil price shock of the past 30 years was followed by an economic recession in the United States.
One camp insists technological progress holds the solution to oil dependence. Our attention should be on developing energy-efficient vehicle technologies and developing fresh energy sources to replace petroleum cleanly and inexpensively
Another approach places an emphasis on conservation. Curbing our demand for petroleum will help reduce U.S. oil dependence and provide an incentive for auto manufacturers to produce cleaner, more energy-efficient vehicles.
The Environmental Element
In any discussion of the environmental responsibility shouldered by the United States, it is important to recognize that the U.S. accounts for 25 percent of the world's economic output.
That said, here goes: More than one-third of the oil shipped by sea is destined for the United States. Air pollution is a worldwide problem, and the U.S. is the largest emitter of manmade greenhouse gases, accounting for 20 percent of all manmade greenhouse emissions. Reduce demand for imported oil, and less will be shipped by sea, with the prospect of fewer oil spills.
Transportation vehicles produce most of the key chemicals that pollute the air, causing smog and health problems. Air quality is poorest in developing industrial nations, but 133 million Americans live in areas that fail at least one National Ambient Air Quality standard. Vehicles with higher fuel economy may produce less pollution over time than vehicles with lower fuel economy.
Global warming is also related to automotive exhaust emissions. Greenhouse gases trap heat and contribute to global warming by keeping a significant percentage of infrared radiation from escaping into space. The concentration of greenhouse gases, especially CO2, has increased substantially since the beginning of the industrial revolution. Natural greenhouse effects contribute to global warming, but the National Academy of Sciences says the increase over the past 150 years is due in large part to human activity.
Energy-related activities are the main sources of U.S. manmade greenhouse gas emissions. U.S. energy policy calls on the federal government to promote the development of fuel-efficient vehicles, support research into cleaner fuels, and implement programs to reduce vehicle miles traveled.
But, says the Environmental Protection Agency on its Web site, citizens can also do their part to help reduce climate change by purchasing a vehicle with higher fuel economy.
MPG and Your Wallet
The Auto Editors of Consumer Guide® road test more than 200 new cars, trucks, minivans, and SUVs per year. They drive these vehicles the way their owners would: urban commuting, suburban shopping, and highway travel. We keep scrupulous fuel-economy records on each vehicle.
In real-world driving, the 8-cylinder SUVs tested average about 13 mpg in city/highway driving. The average is about 15 mpg for 6-cylinder SUVs and minivans, and about the same for most luxury cars. The typical midsize car tested gets approximately 22 mpg, the typical 4-cylinder compact car, about 25 mpg.
According to the American Automobile Association, the average price for a gallon of unleaded regular gas nationally in September 2004 was $1.84. By August 2005, it was $2.33. By September 2005, in the weeks after Hurricane Katrina, the pump price for regular was $3.04.
For the same points in time, the AAA says the national average for a gallon of premium-grade gas was $2.02, $2.56, and $3.34. No one can predict the future cost of a gallon of gas, but these figures show price volatility is a near certainty.
Owners keep a new vehicle an average of seven years. The typical American vehicle racks up about 12,000 miles per year. Using the real-world fuel-economy averages as recorded by Consumer Guide®, and the average price of gas as of September 2005, here's an idea of how much each of these types of vehicles would cost to fuel at 12,000 miles per year.
|LONG-TERM FUEL COSTS
||1 YEAR||7 YEARS|
|Regular-grade fuel at $3.04 per gallon|
|8-cylinder SUV (13 mpg)||$2,806||$19,642|
|6-cylinder SUV, minivan (15 mpg)||$2,432||$17,024|
|Midsize car (22 mpg)
|Compact car (25 mpg)||$1,459||$10,213|
|Premium-grade fuel at $3.34 per gallon|
|Luxury car (15 mpg)
Rising fuel costs are a concern for everyone. In the next section, we'll discuss those rising costs and how they affect us all.
Rising Fuel Costs
Most of the timely tips in this article will help -- whether you drive 1,000 miles a week or never cover that much distance in a month; whether you drive a subcompact, a hybrid, a sports car, or a sport-utility vehicle; whether you agonize daily in rush-hour traffic or seldom stray from uncrowded rural highways.
Much of driving economically is a matter of breaking a few bad habits and substituting some good ones. We've all been warned about "jackrabbit" starts and speeding. Such actions are both dangerous and uneconomical, and yet we see them all the time.
The trouble is, many of us learned to drive at a time when economy was not a high priority and when cars weren't built with thrift in mind. Even the basic scheduled maintenance was mainly for the purpose of boosting performance, not for adding extra miles per gallon.
Americans seldom gave much thought to fuel economy before the Arab Oil Embargo of 1973. The specter of long lines at the gas station, unreliable supply, and fluctuating prices reared again with the fuel crisis of 1979-1980. Those events were wake-up calls, and Detroit and Asian auto-makers responded with lots of gas-sipping compacts. But by the late 1980s, horsepower and performance were back in vogue.
Average fuel economy for passenger cars, after rising steadily for more than a decade, began to decline by 1989. Cars were getting faster, more powerful, more laden with gadgetry -- and gulping more fuel. Americans had evidently decided that a new crisis wasn't going to happen. The popularity of light trucks, notably sport-utility vehicles and pickup trucks, grew quickly in the late 1980s when Ford's F-150 pickup became the best-selling vehicle in America, and trendy was spelled S-U-V.
In short, life on the American road was good. We were paying far less for our automotive fun than were motorists in most European countries -- just as we had for decades. Adjusted for inflation, motor fuel costs in the late '80s had reached their lowest point since the years just after World War II.
Then, in August 1990, Iraq invaded Kuwait. Within a week, the average price of gasoline shot up more than 16 cents a gallon. A month later, prices stabilized somewhat, though at a level 30 cents higher than before the crisis. Suddenly, government officials issued stern warnings about the need for frugality. Polls suggested that many Americans would return to fuel-sipping cars if gas prices reached $1.40 per gallon. More than half claimed they would do so if prices hit $2.00. Many simply said they were already cutting back on driving.
Of course, the modern automobile was already far more frugal than its elephantine ancestors. The average new passenger car achieved 27.8 mpg in 1990. Sure, that was down from a high of 28.6 mpg in 1988, but it was still far thriftier than the 14.2-mpg average of 1974. Maybe America was on the right track after all.
SUVs and Other Light Trucks
Things were also changing at the high-mileage end of the fuel-consumption spectrum. Gas-sipping imports, which had played a major role in redirecting the industry during the 1970s, weren't quite so thrifty anymore. Japanese automakers were veering away from the subcompact and minicar market in which they'd gained their reputations. Instead, they moved upscale, turning to handsome but thirsty performance and luxury models, such as the Infiniti and Lexus sedans introduced for 1990.
By that time, barely 3 percent of shoppers were driving off in cars that yielded 40 mpg or more. About 30 percent of cars available in 1990 offered more than 30 mpg, but few Americans seemed to want one. This is ironic because gas prices, adjusted for inflation, were startlingly high, by U.S. standards.
From 1980 to 1983, pump prices ranged from the inflation-adjusted equivalents of $2.60 a gallon to $2.70 a gallon. Of course, the actual gas prices were much lower during those years, so the bite didn't seem as bad.
Adjusted for inflation, pump prices actually declined from 1985 to 1987, and then leveled off (except during the price spike of 1990-1991 caused by Gulf War I) at about $1.30 to $1.50 a gallon. Then they dropped to $1.00 (adjusted) per gallon in 1998-1999.
That time period marked a high point in America's love affair with the SUV, which was prized for its practical nature, commanding view of the road, presumed safety, and high-class image. And many SUVs, like many pickups, have the added allure of 4-wheel drive -- a system that eats up more gas than 2WD.
SUV sales skyrocketed in the early '90s, and by the end of the decade virtually every automaker that maintained a presence in the United States offered one or more sport-utes -- even Porsche. There was an SUV or pickup for every budget, demographic, and attitude.
SUVs seriously hurt the sales of more economical station wagons and fuel-efficient minivans. In addition, SUV popularity encouraged the production of a proliferation of pickup trucks. These vehicles, as well as a flock of imported and domestic luxury sedans, swallowed gas the way a thirsty horse gulps water.
Global trouble, domestic disaster
The terrorist attacks of September 11, 2001, initiated a gradual but steady climb in pump prices, which accelerated after America's spring 2003 invasion of Iraq. The American war machine required massive amounts of gasoline and other fuels, and as with any war, combat costs soon made their way back to the folks at home.
When Congress legislated new fuel economy standards in 2003 for all cars and light trucks sold in the United States, the passenger-car average was a meager 13.5 mpg, while the light truck average was 11.6 mpg. Those low figures made America vulnerable to future gasoline price hikes, but drivers didn't seem to notice. A devastating price spike was just speculation. And anyway, inflation was low, and if the economy wasn't exactly robust, it did seem to be shaking off some of the effects of the 2000 to 2002 recession.
The $2-per-gallon barrier was shattered in 2004, but prices didn't stop there. Iraqi oil production was crippled by the war, and American demand for gas -- 360 million gallons every day -- continued unabated.
The Environmental Protection Agency's city and highway mileage estimates for 2005, which were put together in late 2004, assumed 2005 gas prices of $1.90 per gallon for regular and $1.95 for premium.
But in 2005 the per-barrel price for crude oil on the world market jumped to $50, startling economists and other analysts. Pump prices rose. Then came $60 per barrel. Pump prices continued to rise. The average cost of a gallon of gas in the United States at the end of summer 2005 approached $3 a gallon, a figure exceeded in many urban areas. Every oil-producing country save Saudi Arabia was producing at full capacity. We wanted more oil, but it wasn't going to come easily. President Bush authorized use of the nation's strategic oil reserve to help keep pump prices in check. Europe, too, released some of its reserves onto the world market.
At the end of August 2005, Hurricane Katrina devastated the Gulf States and badly damaged oil refineries and port facilities vital to America's fuel interests. Because the disaster prompted oil companies to increase the wholesale gas price charged to station owners, pump prices in the days following Katrina rose by 10, 20, 30 cents, and more, in single leaps. Some stations exploited customers with pump prices closer to $4; in the South, some motorists paid as much as $6 per gallon.
When the federal government declared a prohibition on price gouging, the most egregious pump prices declined. But underground tanks at a few independent stations ran dry, and drivers began to worry that big oil stations might have similar shortfalls. By September 2005, some experts looked to the near future and saw an average pump price of $4 per gallon, perhaps higher.
It's easy to see why interest in fuel economy had nearly evaporated prior to 9/11 and again before the American action in Iraq. Americans felt that at $1.50 per gallon, even $2.00, the pleasure-to-pain ratio was acceptable. At $1.50 per gallon the average driver -- who consumes a bit more than 500 gallons each year, traveling just over 10,000 miles -- paid about $750 annually. Two-dollar gas took the average over the $1,000 mark -- a significant amount, but one that Americans were willing to pay. But $3 per gallon means an annual outlay of $1,500, and if you're already paying more than $3, well, you can do the math for yourself.
Still, it's important to note that gas prices in late 2005, adjusted for inflation, were at about the same level as in the early 1980s, and overall improvements in fuel economy meant that drivers paid nearly 40 percent less to drive a mile than they did 20 years ago.
Gasoline remains a bargain in the United States, particularly relative to the retail cost of premium bottled water and other everyday commodities. For example, a 20-ounce cafe mocha costs about $3.50, and although it tastes good, it won't get you nearly as far as a gallon (128 fluid ounces) of gas.
Consider, also, that U.S. gas prices are only about half of what is charged in Europe, where drivers and automakers have learned to adjust. Further, U.S. capacity to refine oil, though compromised by Katrina, was not harmed critically. All of us benefit from the social and economic opportunities made possible by gasoline and the American tradition of personal transport. Calm, sensible driving and buying decisions will see you through almost any fuel-economy challenge.
If you're shopping for a new vehicle while fuel prices are on the rise, there are many factors you can keep in mind to help keep your mpg nice and high. In the next section, we'll discuss vehicle size, weight, and safety features, and how those can impact your fuel economy.
Comparing Vehicle Size, Weight, and Safety for Fuel Efficiency
Vehicle weight is the biggest single enemy of fuel economy. A heavy vehicle simply needs more power than a smaller one to produce comparable acceleration and load-hauling capacity. And that's usually achieved by a larger-displacement engine.
Consumer Guide® real-world fuel-economy tests show that for the same model of vehicle, the version equipped with the larger engine almost always uses more fuel than one with the engine that has fewer cylinders or less displacement. However, in some SUVs and pickup trucks we've tested, the version with the smaller engine averages fewer miles per gallon. In large, heavy vehicles, a larger engine that doesn't have to strain as much can turn out to be more fuel-efficient than the smaller engine choice.
Generally, the larger a vehicle's size, the more it weighs. That isn't an ironclad rule, however. Midsize models loaded with luxury amenities or special-purpose equipment can easily outweigh modestly equipped full-size versions of the same type of vehicle.
Also affecting weight is the job a vehicle is designed to do. Heavy trailer towing or severe off-roading, for example, may require a beefy frame and reinforced suspension components. Those add weight. And convertibles, for instance weigh more than their coupe counterparts.
Size, Weight, and Safety
Simple laws of physics sometimes dictate truths that are hard to swallow when your aim is to save fuel. Large, heavy vehicles have lower real-world fatality rates than smaller, lighter vehicles. But it is not possible to simply conclude that size equals safety. That's because some large vehicles, such as full-size pickup trucks, have higher fatality rates than some categories of passenger vehicles, such as full-size sedans and minivans, which are not as large or as heavy. Much depends on a vehicle's design, the safety features with which it is equipped, and, not least, its driver demographics.
A Closer Look at Vehicle Safety
Fatality rates are generally measured in deaths per 1 million registered vehicles. The ranking of vehicle type by fatality rate can change year to year, depending on variances in reporting and record-keeping. But in general, here is how the vehicle types tend to rank, listed from lowest fatality rate to highest:
- Minivans and large cars (lowest fatality rate)
- Large SUVs
- Midsize cars
- Midsize SUVs
- Large pickup trucks
- Compact SUVs
- Compact cars
- Compact pickup trucks (highest fatality rate)
As you think about the trade-offs between fuel economy and vehicle size, here's a look at some factors that influence the fatality rates of the different types of vehicles.
Minivans tend to be family vehicles and are driven conservatively by a mature, experienced driver population. The same holds true for large cars. Both have generous crush zones and tend to be equipped with such important safety features as head-protecting curtain side airbags and anti-lock brakes. And neither is at a pronounced size disadvantage.
Large SUVs have size and weight on their side, and also are built on sturdy truck frames. That frame enhances their passive crash protection, though this rigid metal understructure, combined with the tall ride height of a full-size SUV, means these vehicles can be deadly to occupants of smaller vehicles in a crash. Large SUVs are not inexpensive, and so tend to be driven by a mature driver population, as well.
The midsize-car category covers the widest range of models, from bargain-priced sedans to luxury/performance models. They have going for them a low center of gravity that resists rollover accidents, and also can be equipped with the latest safety features. But their modest size means they begin to be vulnerable in collisions with larger vehicles, and their diverse owner population includes younger, inexperienced drivers.
Midsize SUVs include both truck-type wagons, wagons that are built on car frames, and the latest blend of car, SUV, and minivan: the crossover wagon. They also cover a broad range of price ranges, safety equipment, and driver demographics.
Large pickup trucks share many of the same vehicle characteristics as large SUVs, primarily ride height and a heavy frame. But the pickup-truck driver population tends to be younger and less family oriented. It's a higher risk demographic that drives less prudently, an important factor in the most deadly type of accident affecting trucks and SUVs: the rollover.
Vehicles with a high center of gravity are less stable in changes of direction and have the highest incidences of rollover accidents. A prime cause of death in rollovers is ejection from the vehicle. Pickup drivers, statistically, wear seatbelts less often than drivers of any other type of vehicle.
Compact SUVs also have a tall ride height and high incidence of rollovers, plus a relatively inexperienced driver population. And they are of a size and weight that does not give them a decided advantage in passive safety.
Compact cars are light and small, and while some are relatively costly, most are expensive transportation for a young, high-risk driving population.
Compact pickup trucks combine the least-desirable safety-related characteristics: relatively small and lightweight, tall center of gravity, high incidence of rollovers, high-risk drivers who tend not to wear seatbelts.
When you're shopping for a fuel-efficient vehicle, you'll want to keep weight and safety in mind. However, don't forget the fact that demographics don't necessarily tell the whole story. Shop for a car that meets your needs, and use the information about vehicle fatality rates to influence, not dictate, your final decision.Does a vehicle's mpg really make a difference? What are those numbers based on? Check out the answers in the next section.
Comparing Vehicle MPG
Automakers are required by law to post their vehicles' fuel-economy ratings, as certified by the federal Environmental Protection Agency (EPA), on the window stickers of most every new vehicle sold in the U.S. The exception is for vehicles having gross-vehicle-weight ratings over 8,500 pounds, which include heavy-duty pickups and the largest SUVs.
The posted information lists the miles per gallon estimate for city driving and for highway driving, and also estimates the fuel economy range that most drivers achieve with that particular model.
For a listing of EPA estimates for all vehicles covered by the program, visit http://www.fueleconomy.gov. As most of us can attest, these "official" ratings rarely reflect our own real-world driving experience. Fuel economy is not a fixed number. Depending on what, how, and where you drive, the differences can be pronounced. Your vehicle's fuel economy will almost always differ from EPA's fuel economy rating.
The EPA ratings estimate the mpg a "typical" driver should get under "typical" city and highway conditions. However, most drivers and driving environments aren't typical, and the factors that affect fuel economy can vary significantly.
EPA vs. Real-World MPG
Here's a sampling of the EPA fuel-economy estimates for a variety of vehicles, and the actual miles-per-gallon averages observed by Consumer Guide® during its road-test program. This road-test program subjects vehicles to a mix of city and highway driving by at least four road-test editors. The cars are tested in the Chicago area and in Southern California, and usually accumulate about 300 miles during the test period. (Note: man. means manual transmission; auto. means automatic transmission; awd means all-wheel drive.)
||EPA City/Hwy||CG® Observed|
|Acura RSX Type-S, man.||23/31||21.3|
|Audi A4 2.0 T, man.
|BMW 325Ci convertible, auto.||19/27||21.9|
|Chevy Cobalt LS sedan, auto.||24/32||28.6|
|Chevy Colorado LS crew cab, auto.||18/23||17.6|
|Chrysler 300 Touring w/AWD, auto.||17/24||19.7|
|Dodge Ram SRT-10, man.
|Ford Five Hundred SEL AWD, convertible
|Ford Mustang Premium, auto.
|Honda Accord EX V6 coupe, man.||20/30||23.2|
|Honda Civic EX coupe, man.
|Honda Odyssey Touring, auto.||20/28||16.4|
|Jaguar S-Type 3.0, auto.
|MINI Cooper convertible, man.||28/36||27.6|
|Saab 9-2X Aero, man.
|Toyota Highlander Base AWD, auto.
|Volkswagen Touareg V8, auto.
|Volvo XC90 V8 AWD, auto.
How New Vehicles Are Tested
Why do the EPA's mileage-per-gallon numbers almost always seem to be higher than the real-world mpg numbers from Consumer Guide®'s testing? It has a lot to do with the way new cars and trucks are evaluated for their energy consumption. While it would seem logical to determine a vehicle's fuel economy by simply filling up the tank, driving it on the road or a test track for a set number of city or highway miles, refilling the tank, and dividing the number of miles driven by the number of gallons consumed, this is not how the experts do it.
In fact, tested vehicles don't reach the pavement at all. Rather, a car or truck's fuel economy is measured under rigidly controlled circumstances in a laboratory using a standardized test that's mandated by federal law. Automakers actually do their own testing and submit the results to the EPA, which reviews the data and confirms about 10 to 15 percent of the ratings itself at the National Vehicles and Fuel Emissions Laboratory.
Each model is tested on what's called a dynamometer, which is like a treadmill for cars. While the engine and transmission drive the wheels, the vehicle never actually moves-just the rollers upon which the wheels are placed. A professional driver runs the vehicle through two standardized driving schedules.
The "city" program is designed to replicate an urban rush-hour driving experience in which the vehicle is started with the engine cold and is driven in stop-and-go traffic with frequent idling. The car or truck is driven for 11 miles and makes 23 stops over the course of 31 minutes, with an average speed of 20 mph and a top speed of 56 mph.
The "highway" program is created to emulate rural and interstate freeway driving with a warmed-up engine, making no stops (both of which ensure maximum fuel economy). The vehicle is driven for 10 miles over a period of 12.5 minutes with an average speed of 48 mph and a top speed of 60 mph. Both tests are performed with the vehicle's air conditioning and other accessories off.
Throughout the test a hose is connected to the vehicle's tailpipe and collects the engine's exhaust. It's the amount of carbon that's present in what's spewed from the exhaust system that's measured to calculate the amount of fuel burned. The EPA claims this is more accurate than using a fuel-gauge to physically measure the amount of gasoline that's being burned. Still, the final test figures are adjusted downward, by 10 percent for city driving and 22 percent in highway mileage, to help reflect the differences between what happens in a lab and out on an actual road.
The EPA and Hybrids
The gap between official and experienced fuel economy can be even wider for owners of gas/electric hybrid-powered vehicles. Most experts feel the EPA's ratings for hybrid vehicles tend to be overstated by a factor of at least 20 percent. This discrepancy can be wider yet if a motorist drives primarily on the highway, where hybrids tend to be less efficient than in stop-and-go city driving conditions (during which the electric motor shoulders more of the effort).
Ironically, the results of ongoing operating tests conducted by the EPA of a dozen hybrid cars in its own fleet significantly contradict their posted fuel-economy ratings. The best the EPA's fleet could muster was a cumulative average of 37.7 mpg for the 2004 Honda Civic, 45.7 mpg for the Honda Insight, and 44.8 mpg for the Toyota Prius. While this is certainly admirable fuel economy, it's still far below the cars' EPA ratings that run as high as 51, 66, and 60 mpg, respectively, for the model years tested.
Why do such discrepancies tend to be more pronounced for hybrids? Experts say it's because basing fuel economy upon the amount of tailpipe exhaust automatically favors gas/electric-powered vehicles. Since some of a hybrid's power comes from an electric motor that automatically produces zero emissions, these figures tend to skew higher than simple miles driven/gallons-consumed computations would otherwise indicate.
Discrepancies Beyond the Lab
In addition to the testing methods used to determine the EPA's ratings, a host of other physical and personal factors contribute to the differences between a vehicle's rated and realized energy consumption. For starters, cars and trucks used for evaluation in the EPA's tests are broken in and are in top mechanical shape.
Also, the cars and trucks subjected to fuel economy testing are "driven" without a full complement of passengers and cargo. Similarly, the vehicles are tested without the air conditioning and other electrical accessories in use.
While the EPA's fuel-economy estimates may not be a completely accurate prediction of the kind of mileage you'll register during your daily commute, it's still valid as a source of comparison when you shop for a new vehicle.
Are you thinking about buying an SUV? Or perhaps you'd prefer one of those new, fuel-efficient hybrids. Can using diesel really save you a few bucks at the tank? In the next section, we'll take a look at all three vehicle types and help you decide if one of them is right for you.
Evaluating Fuel Efficiency of SUVs, Hybrids, and Diesels
Buoyed in great measure by affordable fuel, America in the 1990s turned its automotive appetite to light trucks. The category includes pickups, minivans, and, the models that experienced the fastest-rising popularity of all-sporty-utility vehicles.
In 1980, light-duty trucks accounted for just 12 percent of new vehicle sales. The share was 31 percent by 1990, and reached a high of 54 percent in mid-2004. For SUVs, the share of the U.S. new-vehicle market was just 10 percent in 1994. By 2004, it was 24 percent.
Light-truck sales didn't slip as gas prices rose during 2005, through SUV buyers did begin to switch from thirsty truck-based wagons, such as the Chevrolet Tahoe and Ford Explorer, to lighter-weight and thriftier car-type SUVs, such as the Chevy Equinox and Honda Pilot.
Even after the price shocks following Hurricane Katrina in September 2005, light trucks still were outselling cars, but the lead had shrunk to 51 percent of the market. And sales of large, truck-type SUVs continued to shrink in favor of car-type models.
As a category, light trucks average about 25 percent lower fuel economy than passenger cars. Within light trucks, the miles-per-gallon spectrum starts with full-size pickups and SUVs and the least efficient, followed by truck-type midsize SUVs, with compact and car-based SUVs the most efficient.
Buying with Fuel Economy in Mind
In general, we urge potential SUV buyers to consider their purchase rationally, not emotionally. Sure, SUVs are trendy, and their high ride height and shear size afford a sense of security. But that ride height requires you to climb, not step, in and out. And tall-riding vehicles are more prone to rollover accidents. Minivans offer more usable interior space than any large SUV, and many station wagons afford nearly as much cargo room as a midsize SUV and more than most compacts. The added traction of all-wheel drive is also available in vehicles that are not SUVs.
But if you're committed to an SUV, here's our advice. If you regularly tow a trailer of more than 5,000 pounds, you need the stout truck-type frame and burley V-8 engine that's the bread and butter of the truck-type SUV. And if you frequently travel in severe off-road conditions, the truck-type frame might also serve you well.
But for every other use to which the vast majority of Americans put an SUV, a car-type SUV is the more sensible, and fuel-smart, choice. They ride and handle better, offer a range of 4-cylinder and V-6 powertrains, and most all-wheel drive (AWD) versions do surprisingly well off pavement, too.
Go about picking a fuel-efficient SUV in much the same way you would a frugal car-without expecting as thrifty a result, of course. Consider the choice of available engines and transmissions, and go easy on the weight-adding options.
Four-wheel drive has its good points, but mileage is not ordinarily among them. EPA fuel-economy estimates and Consumer Guide® road test results illustrate the difference. The extra drivetrain components just add too much weight, so even discreet use of four-wheel drive (4WD) carries a big penalty every day, whether it's engaged or not. Not every 4WD vehicle qualifies as an out-and out guzzler; but unless statistics suggest otherwise, assume that you'll pay plenty for the occasional ability to put four drive wheels to the pavement.
If you don't need the off-road traction versatility of true 4WD, all-wheel drive is an attractive alternative. These systems are lighter in weight than 4WD, and actually are more useful on-road because, unlike 4WD, they require no action from the driver to deliver power to all four wheels. Some systems also offer low-range gearing and oth er off-pavement traction aids.
Hybrids and Diesels
Gas/electric hybrid-electric cars and trucks combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools. None of the hybrid cars and trucks on sale in the U.S. require plug-in charging. They instead use a combination of the gas engine's power, and systems that "recapture" otherwise-lost energy from the turning wheels, to recharge the motor's batteries.
Hybrids have grabbed headlines out of proportion to their sales numbers. Though nearly 90,000 hybrid vehicles were sold in the U.S. in 2004, that was only about one half of one percent of the total vehicle market. Leading auto industry analysts say hybrids will top out at just 3 percent of the U.S. market by 2010.
Gas/electric hybrids tend to get better fuel economy in city driving than in highway use. But the bigger surprise has been the gap between the astounding EPA fuel-economy estimates and real-world experience.
This gap was borne out by Consumer Guide® in a six-month evaluation of a 2004 Honda Civic Hybrid with automatic transmission. The EPA rated that vehicle at 48 mpg city, 47 mpg highway. Consumer Guide's® automotive editors drove the vehicle 12,000 miles and averaged 38.3 mpg.
That sort of fuel economy can be duplicated by small, gas-only cars and some diesel cars. But only hybrids combine such high mile-per-gallon returns with low exhaust emissions.
Hybrid cars and SUVs tend to cost more than similar gasoline-powered vehicles. But automakers are increasingly pitching them not as merely fuel-saving purchases but as premium-powertrain vehicles that use the extra muscle supplied by the electric motor in tandem with the gas engine to create vehicles that are both faster and more frugal than gas-only counterparts.
Motorists who were "burned" by the last wave of diesel power in the late 1970s and early 1980s probably wouldn't buy one. Everybody's heard about the horrid reality problems of GM's diesel V-8s, in particular, and the inadequacy of most smaller diesels as well.
Only a handful of diesels remained available through the 1980s, but Mercedes-Benz and Volkswagen are leading a resurgence in diesel availability with engines far superior to earlier versions in silence and performance. For economy, the diesel is hard to beat, delivering as much as 25 percent more mileage (on diesel fuel) than a gasoline engine of similar size.
Buying a new car is confusing enough. In the next section, we'll take a look at the considerations you'll want to keep in mind if buying a fuel-efficient car is your goal.
Buying a Fuel-Efficient Car
Buying with fuel economy in mind doesn't require you to own a vehicle you don't want. Rather, it means shopping for the vehicle that gives the features you want with the best available fuel economy. You'll save money in gas, and do your part to signal auto manufacturers to make more energy-efficient vehicles.
Your first decision is what type of vehicle to drive. Choices range from gas-sipping compacts to gas-guzzling sports utility vehicle, and in between is a bewildering range of cars, trucks, and crossovers. This basic decision is based on a variety of factors: how much you are able or willing to spend on a vehicle, what size or type of vehicle you may actually require, and the emotional component.
In a very real sense, the opportunity for greatest gas savings rests with those whose economic circumstances give them the freedom to choose from a wider variety of vehicle types. If a tight budget is your guide, you may be forced into a smaller, less-expensive car. That means a relatively lightweight vehicle with few gas-draining options and likely a small, efficient engine. If you're in a position to choose from among various sizes and types of vehicles, remember that there are fuel-efficient choices even among seeming gas guzzlers such as sports cars, premium sedans, and SUVs.
Emotion is part of the fabric of the auto world. What your choice of vehicle says about you, what you think it says about you, and how it makes you feel are at the root of more car-buying decisions than many of us might like to admit. But saving fuel is just as emotional, for what it says about you, and how it makes you feel.
Consumer Guide®'s Fuel-Economy Experience
Here are representative samples of the some of most fuel-efficient 2005 models in several vehicle categories as recorded in road tests by the Auto Editors of Consumer Guide®. For an up-to-the-minute look at the fuel economy we recorded for hundreds of new and used cars, go to ConsumerGuide.com.
Please note: AWD for all-wheel drive, 4WD for 4-wheel drive, 2WD for 2-wheel drive, and TDI for turbocharged diesel engine.
- Honda Insight, a 2-seat gas/electric hybrid. A manual-transmission Insight tested in and around Chicago averaged 57.3 mpg. Performance runs and high-speed freeways kept a California test car to 48.9 mpg. An Insight with a continuously variable automatic transmission averaged 48.1 mpg.
- Toyota Prius (a 5-seat hybrid): Test cars averaged 42.6 to 45.2 mpg in normal driving; another did 36.7 including gas-eating performance runs.
- Volkswagen Golf TDI: With manual transmission, the Golf TDI averaged 41.5 mpg.
- Honda Accord/Accord Hybrid: Hybrid model averaged 29.8 mpg over 2,230 miles. In tests of 4-cylinder coupes, manual-transmission models averaged 22.7 to 30.6 mpg, automatic-transmission versions 25.2 mpg. Four-cylinder sedans averaged 22.4 to 26.1 mpg. Automatic-transmission sedans averaged 22.4 mpg in city/highway mix, 26.1 mpg in mostly highway driving.
- Volkswagen Passat TDI (diesel): Test TDI wagons averaged 28.7 to 35.3 mpg.
Premium Compact Cars
- Acura TSX: Test manual-transmission TSXs averaged 22.6 to 30.2 mpg, test automatics 26.3 to 26.4 mpg. Premium-grade fuel required.
- Audi A4: Test manual-transmission 2.0 T Avants averaged 20.3 to 22.5 mpg. Test V6 Cabriolets with CVT averaged 19.8 to 20.7 mpg. S4 Cabriolet with manual transmission averaged 14.1, manual S4 sedans 16.1 to 18.4 mpg. Audi recommends premium-grade fuel for all A4s.
- BMW 3-Series sedan: Test manual-transmission 330i averaged 22.3 mpg in mixed city/highway driving. BMW recommends premium-grade fuel for both engines.
Premium Midsize Cars
- Mercedes-Benz E-320 CDI (diesel): Test E320 CDIs averaged 33.7 mpg in mostly highway driving, 27 to 29.2 with more city driving.
- Chrysler Town & Country/Dodge Caravan: Test Town & Country with 3.8 V6 averaged 18.5 mpg; expect about the same for similar Grand Caravan. Overburdened 3.3 should average 15 to 17 mpg in Grands. Test regular-length 4-cylinder model averaged 19.8 in city/highway mix.
- Mazda MPV: Averaged 21.9 mpg. That's better than the minivan norm, but our test included lots of highway driving.
- Toyota Sienna: AWD model averaged 18 mpg over 19,780 mi. in a test heavy on highway driving. (Toyota recommends premium-grade fuel.)
- Ford Escape/Escape Hybrid: Test 2WD 4-cylinder Escape averaged 20.5 mpg. Test AWD V6 Escapes and Tributes averaged 17.5 to 19.2 mpg in mixed city/highway driving. Test AWD Escape Hybrid averaged 28.4 mpg in mixed driving, 23.5 mpg in city driving that included gas-eating performance tests.
- Honda Element: Test automatic-transmission AWD averaged 21.2 mpg. Test manual-transmission 2WD returned 22 mpg, including gas-eating performance tests. Test manual-transmission AWD averaged 19.2 in mostly city driving.
- Mitsubishi Outlander: In a city/highway mix of driving and with automatic transmission, test 2WD Outlander averaged 22.5 mpg, AWD version 22.3.
- Subaru Forester: Test automatic-transmission models averaged 19.4 to 24.2 mpg. Expect slightly higher with manual. Test XT with automatic averaged 18.5 in mostly highway driving. XT requires premium-grade fuel; other models use regular.
- Toyota Highlander 4-cylinder and Hybrid: Test Hybrid averaged 26.3 mpg in a mix of city and highway driving. Test 4-cylinder AWD averaged 19.6 mpg in mixed driving. Toyota recommends regular-grade fuel for 4-cylinder models, premium for Hybrid.
- Ford Freestyle: Test AWD model averaged 19.7 mpg in an even city/highway driving mix and 18.7 including gas-eating performance runs.
- Nissan Murano: Test 2WD Muranos averaged 19.6 to 20.1 mpg in mixed city/highway driving-quite good for a V6 midsize SUV. Test AWD model averaged 16.3 in mostly city driving. Nissan recommends 91-octane fuel.
- Chevrolet Tahoe: Chevrolet Tahoe with 4.8-liter V8 averaged 12.2 mpg.
- Toyota Sequoia: Test 4WD versions averaged 13.8 to 15.6 mpg.
Premium Midsize SUVs
- Lexus RX 330 and 400h (400h is a hybrid): In our tests, 2WD 330 averaged 14.2 mpg, RX 400h 22.7, both with mostly city driving and gas-eating performance runs. AWD 330 averaged 20.6 mpg mostly on highway. Premium-grade fuel required for all.
Compact Pickup Trucks
- Chevrolet Colorado: Extended-cab 2WD 5-cylinder averaged 18.8 mpg. Crew Cab 4WD 5-cylinder averaged 18.1. Both were driven mostly highway. Manual-transmission 2WD 4-cylinder regular cab averaged 18.1 mpg in mostly city driving.
- Honda Ridgeline: Averaged 16.2 to 18.3 mpg in mixed city/highway driving.
Options such as all-wheel drive, automatic transmission, and even power windows can reduce your fuel efficiency. In the last section, we'll take a look at various options and the negative impact they'll have on your mileage.
Choosing Options for a Fuel-Efficient Car
When you're shopping for a fuel-efficient car or truck, common sense suggests the smallest available engine delivers the highest mpg. In the real world, that's not always the case. A powerplant that strains, wheezing out inadequate horsepower and torque for the job, just might send you to the gas pump more often rather than less often. To say nothing of the fact the life of an overworked engine is not usually a long one. So while a 4-cylinder engine tends to be more economical than a V-6 powering the same car, and a V-6 is more frugal than a V-8, smaller isn't always the wisest choice.
What's needed is the best match between car size/weight and engine output. Too small, and it's often overworked, never realizing its economy potential. Too big, and it guzzles more than necessary to get the job done. To choose between a standard and optional engine, check the EPA ratings and the real-world road tests -- not only for mileage figures but for comments on the sufficiency or lack of usable power.
Turbochargers and Superchargers
At first glance, a turbo sounds like the high-efficiency choice for both performance and economy. After all, it doesn't drain engine power, but makes use of exhaust gases to rotate the high-speed turbine. Better yet, it comes into play only when needed-only when tromping hard on the gas pedal for a quick burst of extra power. That extra jolt sucks up plenty of extra fuel, however, as it shoves an oversized air/fuel charge into the engine. If rarely used, it might not hurt mileage much. But how many people buy a turbo and keep their foot light on the pedal? Superchargers, driven directly by the engine, act as a constant drag and cost a bundle in mileage.
Choose an Economical Axle Ratio
Plenty of buyers never realize there's a choice. Often there isn't; but many pickup trucks and some performance-oriented cars are offered with a selection of ratios. As a rule, the lower the number, the greater its economy potential. That's because it allows the engine to run slower for a given road speed. An "economy" axle has a ratio below 3:1 or so. "Performance" axles, which deliver quicker acceleration and are better suited to towing trailers, might come to more that 4:1. The perfect selection depends on the type of driving you do.
Shift for Yourself
A quick glance at the EPA ratings for cars available with a choice of manual and automatic transmissions makes it clear that manual gearboxes are the only choice for peak economy. Seldom does the city-driving estimate for automatic come closer than 2 to 3 mpg to the manual-shift figure. In some cases, the difference is similar on the highway; other automatics achieve better results, rivaling a "stick" when up to speed. Compare the figures before deciding, but remember that high mpg wi th a manual comes only when it's shifted with some expertise.
Many cars and minivans are available with all-wheel drive (AWD). The AWD systems in cars and minivans is intended as an all-weather traction aid, and not designed for off-road duty. Thus, it doesn't have the weighty, heavy-duty componentry of most four-wheel drive (4WD) and AWD systems in pickup trucks and SUVs.
AWD cars and minivans do tend to use more fuel than their 2-wheel drive counterparts. This is due less to any added drag placed on the powertrain by AWD as more to the 100 to 200 pounds the AWD system adds to the weight of the vehicle. But the fuel-mileage difference isn't pronounced, and while AWD adds to the purchase price of the vehicle, it's well worth considering if you frequently travel wet or snowy roads.
Amenities and Fuel Economy
To some people, comfort is a heated leather seat in the winter. Others take comfort in knowing they're eking out every last mile from each gallon of gas they consume.
Nearly every luxury amenity adds weight and drains power, both of which are the enemies of fuel economy-and performance. You'll either drag down the efficiency of your engine, or have to shell out for a larger, less efficient engine designed to shrug off the extra strain placed on it by the following power convenience features.
Air conditioning: Air conditioning is standard on all but a few low-cost compact cars and trucks. It's a necessity in many parts of the country. And even when the weather isn't sweltering, the ability to drive with windows closed can reduce driver fatigue on long trips or in noisy city traffic. Still, an air conditioner adds a hundred pounds or so to the car's weight and drains energy even if the switch is never flipped on. In the city, you're talking about as much as 3 to 4 lost mpg whenever it's used. Can you learn to live without it?
Sunroofs: Just like an open window, an open sunroof adds drag to the car's ability to slice through the air. And a sunroof's sliding glass or metal panel, electric motor, and the tracks and reinforcements upon which it rides to open and close all add lots of extra weight to your vehicle.
Cruise control: Cruise control can boost mileage if it's used properly on long, flat stretches; but can drain if operated carelessly. If you do plenty of highway driving, it may be worth the price in both economy and convenience.
Roof rack: Is it really worth hauling a wind catcher all year long just to have it available during vacation time? If so, try to avoid putting too much bulky stuff up there. An older, non-aero sedan or wagon might not be affected as much as a modern vehicle, in terms of mileage.
Colors: Light colors reflect sunlight and help keep the interior cool. Dark colors do the opposite. Color choice, then, affects the need to use the air conditioner or heater.
Power seats, windows, door locks: Handy, yes; economical, no. Each accessory draws energy or adds weight, decreasing mileage.
Before you buy a fuel-efficient car, consider which of these options is really necessary to you, and weigh each option against the fuel economy you'll sacrifice.
Related HowStuffWorks Articles
- Quiz Corner: Car Buying Quiz
- How to Drive Economically
- How Car Engines Work
- How Continuously Variable Transmissions Work
- How Force, Power, Torque and Energy Work
- How Gasoline Works
- How Gas Prices Work
- How Horsepower Works
- How Manual Transmissions Work
- What speed should I drive to get maximum fuel efficiency?
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