Du milieu des années 1970 à 1990, la consommation moyenne de carburant de tous les véhicules sur la route aux États-Unis a doublé, passant d'environ 14 à 28 miles par gallon (mpg). En 2005, il était tombé à 24 mpg. Conduire un véhicule économe en carburant vous fera économiser de l'argent sur l'essence, bien sûr, mais une telle décision a d'autres effets plus larges.
La nature a mis plus de 200 millions d'années pour développer tout le pétrole sous la surface de la terre. L'humanité n'a eu besoin que de 200 ans pour en consommer la moitié. Si les taux de consommation actuels se maintiennent, le département américain de l'Énergie affirme que les ressources mondiales restantes de pétrole conventionnel seraient épuisées dans 40 ans.
Environ 60 % du pétrole consommé dans le monde alimente les véhicules de transport, et la moitié va aux voitures particulières et aux camions légers. Il n'est pas surprenant que les États-Unis, le premier moteur économique mondial, importent et consomment également plus de pétrole que tout autre pays.
Suivant
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La question de savoir si la consommation de pétrole de l'Amérique est disproportionnée est un formidable sujet de débat, que nous n'aborderons pas ici. Et qu'il reste au monde 40 ou 140 ans de pétrole, la réalité du marché est la suivante :à mesure que les ressources pétrolières diminuent et que le pétrole devient d'un coût prohibitif à localiser et à extraire, l'humanité remplacera le pétrole comme principale source d'énergie parce que les formes alternatives d'énergie sera tout simplement plus économique.
Pourtant, brûler moins d'essence dans nos véhicules affectera le rythme auquel le pétrole est consommé. Dans cet article, nous verrons comment vous pouvez faire votre part en achetant une voiture économe en carburant, y compris comment comparer différentes marques et modèles. Nous vous donnerons même des conseils sur la façon d'évaluer les miles par gallon et comment rechercher la climatisation et d'autres fonctionnalités que vous souhaitez avec la meilleure économie de carburant disponible.
Plus important encore, la conservation du carburant aura un impact sur la demande de pétrole. Et cela a des conséquences politiques, technologiques et environnementales importantes.
Dépendance vis-à-vis du pétrole importé
Les transports représentent les deux tiers de l'utilisation du pétrole aux États-Unis et, en 2005, l'Amérique dépendait des importations pour 55 % de son pétrole, le pourcentage le plus élevé jamais enregistré. Au fur et à mesure que les ressources nationales seront épuisées, cette dépendance vis-à-vis du pétrole étranger augmentera. Quelque 70 % des réserves mondiales de pétrole se trouvent au Moyen-Orient, sous le contrôle du cartel pétrolier de l'OPEP.
Dans le passé, la dépendance au pétrole a eu un effet profond sur l'économie américaine. Le ministère de l'Énergie calcule que les chocs pétroliers et la manipulation des prix par le cartel de l'OPEP de 1979 à 2000 ont coûté à l'économie américaine environ 7 000 milliards de dollars - presque autant que nous avons dépensé pour la défense nationale au cours de la même période, et plus que les paiements d'intérêts sur la dette nationale.
Avec une dépendance mondiale croissante vis-à-vis du pétrole de l'OPEP, de futurs chocs de prix sont possibles. Chaque choc pétrolier majeur des 30 dernières années a été suivi d'une récession économique aux États-Unis.
Un camp insiste sur le fait que le progrès technologique détient la solution à la dépendance au pétrole. Notre attention devrait se porter sur le développement de technologies de véhicules économes en énergie et sur le développement de nouvelles sources d'énergie pour remplacer le pétrole de manière propre et peu coûteuse
Une autre approche met l'accent sur la conservation. Réduire notre demande de pétrole contribuera à réduire la dépendance pétrolière des États-Unis et incitera les constructeurs automobiles à produire des véhicules plus propres et plus économes en énergie.
L'élément environnemental
Dans toute discussion sur la responsabilité environnementale assumée par les États-Unis, il est important de reconnaître que les États-Unis représentent 25 % de la production économique mondiale.
Cela dit, voilà :plus d'un tiers du pétrole transporté par voie maritime est destiné aux États-Unis. La pollution de l'air est un problème mondial et les États-Unis sont le plus grand émetteur de gaz à effet de serre d'origine humaine, représentant 20 % de toutes les émissions de gaz à effet de serre d'origine humaine. Réduisez la demande de pétrole importé et moins de pétrole sera expédié par voie maritime, avec la perspective de moins de déversements de pétrole.
Les véhicules de transport produisent la plupart des principaux produits chimiques qui polluent l'air, causant du smog et des problèmes de santé. La qualité de l'air est la plus mauvaise dans les pays industrialisés en développement, mais 133 millions d'Américains vivent dans des zones qui ne répondent pas à au moins une norme nationale de qualité de l'air ambiant. Les véhicules à économie de carburant plus élevée peuvent produire moins de pollution au fil du temps que les véhicules à faible économie de carburant.
Le réchauffement climatique est également lié aux émissions de gaz d'échappement des automobiles. Les gaz à effet de serre emprisonnent la chaleur et contribuent au réchauffement climatique en empêchant un pourcentage important du rayonnement infrarouge de s'échapper dans l'espace. La concentration de gaz à effet de serre, en particulier de CO2, a considérablement augmenté depuis le début de la révolution industrielle. Les effets de serre naturels contribuent au réchauffement climatique, mais l'Académie nationale des sciences affirme que l'augmentation au cours des 150 dernières années est due en grande partie à l'activité humaine.
Les activités liées à l'énergie sont les principales sources d'émissions de gaz à effet de serre d'origine humaine aux États-Unis. La politique énergétique américaine demande au gouvernement fédéral de promouvoir le développement de véhicules économes en carburant, de soutenir la recherche de carburants plus propres et de mettre en œuvre des programmes visant à réduire les kilomètres parcourus par les véhicules.
Mais, indique l'Environmental Protection Agency sur son site Web, les citoyens peuvent aussi faire leur part pour aider à réduire le changement climatique en achetant un véhicule plus économe en carburant.
MPG et votre portefeuille
Les éditeurs automobiles de Consumer Guide® testent plus de 200 nouvelles voitures, camions, mini-fourgonnettes et VUS par an. Ils conduisent ces véhicules comme le feraient leurs propriétaires :déplacements urbains, achats en banlieue et déplacements sur l'autoroute. Nous gardons des dossiers scrupuleux sur la consommation de carburant de chaque véhicule.
En conduite réelle, les VUS 8 cylindres testés consomment en moyenne environ 13 mpg en conduite ville/autoroute. La moyenne est d'environ 15 mpg pour les SUV et les mini-fourgonnettes à 6 cylindres, et à peu près la même pour la plupart des voitures de luxe. La voiture de taille moyenne typique testée obtient environ 22 mpg, la voiture compacte typique à 4 cylindres, environ 25 mpg.
Selon l'American Automobile Association, le prix moyen d'un gallon d'essence ordinaire sans plomb à l'échelle nationale en septembre 2004 était de 1,84 $. En août 2005, il était de 2,33 $. En septembre 2005, dans les semaines qui ont suivi l'ouragan Katrina, le prix à la pompe du produit ordinaire était de 3,04 $.
Pour les mêmes moments, l'AAA indique que la moyenne nationale pour un gallon d'essence de qualité supérieure était de 2,02 $, 2,56 $ et 3,34 $. Personne ne peut prédire le coût futur d'un gallon d'essence, mais ces chiffres montrent que la volatilité des prix est une quasi-certitude.
Les propriétaires conservent un véhicule neuf en moyenne sept ans. Le véhicule américain typique parcourt environ 12 000 miles par an. En utilisant les moyennes réelles d'économie de carburant telles qu'enregistrées par Consumer Guide® et le prix moyen de l'essence en septembre 2005, voici une idée du coût de chacun de ces types de véhicules pour faire le plein à 12 000 milles par an.
| COÛTS DE CARBURANT À LONG TERME | 1 AN | 7 ANS |
| Carburant de qualité ordinaire à 3,04 $ le gallon | ||
| SUV 8 cylindres (13 mpg) | 2 806 USD | 19 642 USD |
| VUS 6 cylindres, monospace (15 mpg) | 2 432 USD | 17 024 $ |
| Voiture intermédiaire (22 mpg) | 1 658 $ | 11 606 USD |
| Voiture compacte (25 mpg) | 1 459 USD | 10 213 USD |
| Carburant de qualité supérieure à 3,34 $ le gallon | ||
| Voiture de luxe (15 mpg) | 2 672 $ | 18 704 USD |
La hausse des prix du carburant est une préoccupation pour tout le monde. Dans la section suivante, nous discuterons de ces coûts croissants et de la manière dont ils nous affectent tous.
Contenu
La plupart des conseils opportuns de cet article vous aideront - que vous conduisiez 1 000 miles par semaine ou que vous ne parcouriez jamais autant de distance en un mois; que vous conduisiez une sous-compacte, une hybride, une voiture de sport ou un véhicule utilitaire sport ; que vous agonisiez quotidiennement dans la circulation aux heures de pointe ou que vous vous écartiez rarement des autoroutes rurales peu fréquentées.
Une grande partie de la conduite économique consiste à briser quelques mauvaises habitudes et à en remplacer de bonnes. Nous avons tous été avertis des démarrages et des excès de vitesse "jackrabbit". De telles actions sont à la fois dangereuses et non rentables, et pourtant nous les voyons tout le temps.
Le problème, c'est que beaucoup d'entre nous ont appris à conduire à une époque où l'économie n'était pas une priorité absolue et où les voitures n'étaient pas construites dans un souci d'économie. Même l'entretien planifié de base visait principalement à améliorer les performances, et non à ajouter des kilomètres supplémentaires par gallon.
Les Américains ont rarement beaucoup réfléchi à l'économie de carburant avant l'embargo arabe sur le pétrole de 1973. Le spectre des longues files d'attente à la station-service, de l'approvisionnement peu fiable et de la fluctuation des prix a de nouveau surgi avec la crise du carburant de 1979-1980. Ces événements ont été des appels au réveil, et les constructeurs automobiles de Detroit et d'Asie ont répondu avec de nombreuses compactes à siroter de l'essence. Mais à la fin des années 1980, la puissance et la performance étaient de retour à la mode.
La consommation moyenne de carburant des voitures particulières, après avoir augmenté régulièrement pendant plus d'une décennie, a commencé à décliner en 1989. Les voitures devenaient plus rapides, plus puissantes, plus chargées de gadgets et consommaient plus de carburant. Les Américains avaient manifestement décidé qu'une nouvelle crise n'allait pas se produire. La popularité des camions légers, notamment des véhicules utilitaires sport et des camionnettes, a rapidement augmenté à la fin des années 1980 lorsque le pick-up F-150 de Ford est devenu le véhicule le plus vendu aux États-Unis.
Bref, la vie sur la route américaine était belle. Nous payions beaucoup moins pour notre plaisir automobile que les automobilistes de la plupart des pays européens, comme nous l'avons fait pendant des décennies. Ajustés en fonction de l'inflation, les prix des carburants à la fin des années 80 avaient atteint leur point le plus bas depuis les années qui ont suivi la Seconde Guerre mondiale.
Puis, en août 1990, l'Irak a envahi le Koweït. En une semaine, le prix moyen de l'essence a bondi de plus de 16 cents le gallon. Un mois plus tard, les prix se sont quelque peu stabilisés, mais à un niveau supérieur de 30 centimes à celui d'avant la crise. Soudain, les responsables gouvernementaux ont émis des avertissements sévères sur la nécessité de faire preuve de frugalité. Les sondages ont suggéré que de nombreux Américains reviendraient aux voitures à faible consommation de carburant si le prix de l'essence atteignait 1,40 $ le gallon. Plus de la moitié ont affirmé qu'ils le feraient si les prix atteignaient 2,00 $. Beaucoup ont simplement dit qu'ils réduisaient déjà leur conduite.
Bien sûr, l'automobile moderne était déjà beaucoup plus frugale que ses ancêtres éléphantesques. La voiture neuve moyenne atteignait 27,8 mpg en 1990. Bien sûr, c'était en baisse par rapport au sommet de 28,6 mpg en 1988, mais c'était encore beaucoup plus économe que la moyenne de 14,2 mpg de 1974. Peut-être que l'Amérique était sur la bonne voie après tout.
VUS et autres camions légers
Les choses changeaient également à l'extrémité du kilométrage élevé du spectre de consommation de carburant. Les importations d'essence, qui avaient joué un rôle majeur dans la réorientation de l'industrie au cours des années 1970, n'étaient plus aussi économes. Les constructeurs automobiles japonais s'éloignaient du marché des sous-compactes et des mini-voitures dans lequel ils avaient acquis leur réputation. Au lieu de cela, ils sont passés au haut de gamme, se tournant vers des modèles de performance et de luxe beaux mais assoiffés, comme les berlines Infiniti et Lexus introduites pour 1990.
À ce moment-là, à peine 3 % des acheteurs partaient dans des voitures d'une consommation de 40 mpg ou plus. Environ 30 % des voitures disponibles en 1990 offraient plus de 30 mpg, mais peu d'Américains semblaient en vouloir une. C'est ironique, car les prix de l'essence, corrigés de l'inflation, étaient étonnamment élevés, selon les normes américaines.
De 1980 à 1983, les prix à la pompe ont varié entre les équivalents ajustés en fonction de l'inflation de 2,60 $ le gallon à 2,70 $ le gallon. Bien sûr, les prix réels de l'essence étaient beaucoup plus bas au cours de ces années, donc la piqûre ne semblait pas aussi grave.
Ajustés en fonction de l'inflation, les prix à la pompe ont en fait diminué de 1985 à 1987, puis se sont stabilisés (sauf pendant la flambée des prix de 1990-1991 causée par la Première Guerre du Golfe) à environ 1,30 $ à 1,50 $ le gallon. Puis ils sont tombés à 1,00 $ (ajusté) par gallon en 1998-1999.
Cette période a marqué un point culminant dans l'histoire d'amour de l'Amérique avec le SUV, qui était apprécié pour sa nature pratique, sa vue imprenable sur la route, sa sécurité présumée et son image de grande classe. Et de nombreux SUV, comme de nombreux pick-up, ont en plus l'allure d'un 4x4, un système qui consomme plus d'essence qu'un 2WD.
Les ventes de SUV ont explosé au début des années 90 et, à la fin de la décennie, pratiquement tous les constructeurs automobiles qui maintenaient une présence aux États-Unis proposaient un ou plusieurs véhicules sportifs, même Porsche. Il y avait un SUV ou un pick-up pour chaque budget, groupe démographique et attitude.
Les SUV ont sérieusement nui aux ventes de breaks plus économiques et de mini-fourgonnettes économes en carburant. De plus, la popularité des VUS a encouragé la production d'une prolifération de camionnettes. Ces véhicules, ainsi qu'un troupeau de berlines de luxe importées et nationales, avalaient de l'essence comme un cheval assoiffé avale de l'eau.
Problème mondial, catastrophe nationale
Les attentats terroristes du 11 septembre 2001 ont amorcé une hausse graduelle mais régulière des prix à la pompe, qui s'est accélérée après l'invasion américaine de l'Irak au printemps 2003. La machine de guerre américaine nécessitait d'énormes quantités d'essence et d'autres carburants, et comme dans toute guerre, les coûts de combat revenaient rapidement aux gens à la maison.
Lorsque le Congrès a légiféré de nouvelles normes d'économie de carburant en 2003 pour toutes les voitures et camions légers vendus aux États-Unis, la moyenne des voitures particulières était de 13,5 mpg, tandis que la moyenne des camions légers était de 11,6 mpg. Ces faibles chiffres ont rendu l'Amérique vulnérable aux futures hausses des prix de l'essence, mais les conducteurs n'ont pas semblé s'en apercevoir. Une flambée des prix dévastatrice n'était que de la spéculation. Et de toute façon, l'inflation était faible, et si l'économie n'était pas exactement robuste, elle semblait se débarrasser de certains des effets de la récession de 2000 à 2002.
La barrière de 2 $ le gallon a été brisée en 2004, mais les prix ne se sont pas arrêtés là. La production pétrolière irakienne a été paralysée par la guerre, et la demande américaine de gaz - 360 millions de gallons par jour - s'est poursuivie sans relâche.
Les estimations du kilométrage urbain et routier de l'Environmental Protection Agency pour 2005, qui ont été rassemblées à la fin de 2004, supposaient des prix de l'essence pour 2005 de 1,90 $ le gallon pour le carburant ordinaire et de 1,95 $ pour le carburant premium.
Mais en 2005, le prix du baril de pétrole brut sur le marché mondial a bondi à 50 dollars, surprenant les économistes et autres analystes. Les prix à la pompe ont augmenté. Puis vint 60 $ le baril. Les prix à la pompe ont continué d'augmenter. Le coût moyen d'un gallon d'essence aux États-Unis à la fin de l'été 2005 approchait les 3 $ le gallon, un chiffre dépassé dans de nombreuses zones urbaines. Tous les pays producteurs de pétrole, à l'exception de l'Arabie saoudite, produisaient à pleine capacité. Nous voulions plus de pétrole, mais cela n'allait pas venir facilement. Le président Bush a autorisé l'utilisation de la réserve stratégique de pétrole du pays pour aider à contrôler les prix à la pompe. L'Europe aussi a libéré une partie de ses réserves sur le marché mondial.
Fin août 2005, l'ouragan Katrina a dévasté les États du Golfe et gravement endommagé les raffineries de pétrole et les installations portuaires vitales pour les intérêts pétroliers américains. Parce que la catastrophe a incité les compagnies pétrolières à augmenter le prix de gros du gaz facturé aux propriétaires de stations, les prix à la pompe dans les jours qui ont suivi Katrina ont augmenté de 10, 20, 30 cents et plus, en un seul bond. Certaines stations ont exploité des clients avec des prix à la pompe plus proches de 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.
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:
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.
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.)
| 2005 Vehicle | EPA City/Hwy | CG® Observed |
| Acura RSX Type-S, man. | 23/31 | 21.3 |
| Audi A4 2.0 T, man. | 22/31 | 22.5 |
| 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. | 9/15 | 9.2 |
| Ford Five Hundred SEL AWD, convertible | 20/27 | 18.3 |
| Ford Mustang Premium, auto. | 19/25 | 20.4 |
| Honda Accord EX V6 coupe, man. | 20/30 | 23.2 |
| Honda Civic EX coupe, man. | 32/37 | 28.3 |
| Honda Odyssey Touring, auto. | 20/28 | 16.4 |
| Jaguar S-Type 3.0, auto. | 18/26 | 19.4 |
| MINI Cooper convertible, man. | 28/36 | 27.6 |
| Saab 9-2X Aero, man. | 20/26 | 20.1 |
| Toyota Highlander Base AWD, auto. | 21/25 | 19.2 |
| Volkswagen Touareg V8, auto. | 14/18 | 12.2 |
| Volvo XC90 V8 AWD, auto. | 16/20 | 15.0 |
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.
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.
Nix 4WD if Economy is Your Goal
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 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.
Compact Cars
Midsize Cars
Premium Compact Cars
Premium Midsize Cars
Minivans
Compact SUVs
Midsize SUVs
Large SUVs
Premium Midsize SUVs
Compact Pickup Trucks
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.
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.
All-Wheel Drive
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.
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