Sport utility vehicle
From Free net encyclopedia
A sport utility vehicle, or SUV, is a type of passenger vehicle which combines passenger-carrying and load-hauling abilities with the versatility of a pickup truck. Most SUVs are designed with a roughly square cross-section, an engine compartment, a combined passenger and cargo compartment, and no dedicated trunk. Most mid-size and full-size SUVs have 5 or more seats, and a cargo area directly behind the last row of seats. Mini SUVs, such as the Jeep Wrangler, may have fewer seats.
It is known in some countries as an off-roader or four wheel drive, often abbreviated to 4WD or 4x4, and pronounced "four-by-four". More recently, SUVs designed primarily for driving on roads have grown in popularity. A new category, the crossover SUV uses car components for lighter weight and better fuel economy.
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Design characteristics
SUVs were traditionally derived from light truck platforms, but have developed to have the general shape of a station wagon. SUVs are typically taller, though, with a roughly square cross-section.
SUVs typically have higher seating than a station wagon and can be equipped with four wheel drive, providing an advantage in low traction environments. The design also allows for a large engine compartment, and many SUVs have large V-6 or V-8 engines. In countries where fuel is more expensive, buyers often opt for diesel engines, which have better fuel efficiency, and given that diesel fuel itself is often much cheaper than gasoline.
History
Sport utility vehicles were originally descended from commercial and military vehicles such as the Jeep and Land Rover. In fact, that many SUVs have a squarish design is partially due to the Jeep, which was manufactured that way. <ref>Keith Bradsher. High and Mighty: SUVs--The World's Most Dangerous Vehicles and How They Got That Way. Published by PublicAffairs. ISBN 1586482033</ref> SUVs have been popular for many years with rural buyers due to their off-road capabilities. In the last 25 years, and even more in the last decade, they have become popular with urban buyers. Consequently, more modern SUVs often come with more luxury features and some crossover SUVs, such as the BMW X5, the Acura MDX, and the Toyota RAV4, have adopted lower ride heights and car chassis to better accommodate their use for on-road driving.
Popularity
SUVs became popular in the United States, Canada, and Australia, especially in the 1990s and early 2000s, for a variety of reasons. Buyers became drawn to their large cabins, higher ride height, and perceived safety when in the market for a new vehicle. Additionally, most full-size SUVs have far greater towing capacities than conventional cars, allowing owners to tow RVs, trailers, and boats with relative ease, adding to the utilitarian image.
A large growth in SUV popularity and sales is due to advertisement targeted towards women. Women constitute more than half of SUV drivers, and SUVs are the most popular vehicle choice of women in the United States.
The most common reason for SUV popularity cited by owners was their safety advantage in a collision with regular cars. Some of their success is also due to their image, a substantial factor for many buyers. In the late 1990s and early 2000s, vehicle manufacturers sold the image of SUVs very effectively, with per-vehicle profits substantially higher than other automobiles. Historically, their simple designs and often outdated technology (by passenger car standards) often made the vehicles cheaper to make than comparably-priced cars. Still, SUVs are more expensive than sedans of similar quality and features.
In the mid 2000s, however, their popularity has waned, due to higher gasoline prices after a period of low prices when SUVs became popular. Current model SUVs take into account that 98% of SUV owners never offroad. As such, SUVs now have lower ground clearance and suspension designed primarily for paved road usage.
SUVs in remote areas
SUVs are often used in places such as the Australian Outback, Africa, the Middle East, and most of Asia, which have limited paved roads and require the vehicle to have all-terrain handling, increased range, and storage capacity. The low availablity of spare parts and the need to carry out repairs quickly allow model vehicles with the bare minimum of electric and hydraulic systems to predominate. Typical examples are the Land Rover, the Toyota Land Cruiser and the Lada Niva.
SUVs targeted for use in civilization have traditionally originated from their more rugged all-terrain counterparts. For example the Hummer H1 is derived from the HMMWV developed for the US Armed Forces.
Other names
Outside of North America and India, these vehicles are known simply as four-wheel-drives, often abbreviated to "4WD" or "4x4". They are classified as cars in countries such as the UK where the U.S. distinction between cars and 'light trucks' is not used. In Australia, the automotive industry and press have recently adopted the term SUV in place of four wheel drive in the description of vehicles and market segments. "Utility" or "ute" refers to an automobile with a flatbed rear or pick-up, typically seating two passengers and is often used by tradesmen, and is typically not a 4WD vehicle.
SUVs in recreation and motorsport
SUVs are also used to explore off-road places otherwise unreachable by vehicle or for the sheer enjoyment of the driving. In Australia, China, Europe, South Africa and the U.S. at least, many 4WD clubs have been formed for this purpose. Modified SUVs also take part in races, most famously in the Paris-Dakar Rally, and the Australian Safari.
Criticism
The explosive growth in SUV ownership has attracted a large amount of criticism, mainly of the risks to other road users and the environment, but also on the basis that the perceived benefits to the vehicle owner are illusory or exaggerated.
Safety
Image:Ford Excursion and Toyota Camry.jpg
Safety is a common point of criticism. The majority of modern automobiles are constructed by a method called unibody or monocoque construction, whereby a steel body shell absorbs the impacts of collisions in crumple zones. Many SUVs, on the other hand, are constructed in the traditional manner of light trucks: body-on-frame, which, when negligently designed can provide a comparatively lower level of safety. However, some SUVs have designs based on unibody construction: the Ford Escape/Mazda Tribute, Lexus RX 330 and RX 400h, Hyundai Santa Fe, and Acura MDX are some examples. In fact, the Jeep Cherokee/Liberty (1984 on) and Grand Cherokee (1993 on) have used unibody construction from the start.
Risk to other drivers
Because of SUVs' greater height and weight, and often usage of body-of-frame constructions, it is documented many SUVs hurt overall public road safety by slightly reducing risk for people inside the SUV, but substantially increasing risk for those outside the SUV (in other vehicles or on foot). This is due to the SUVs' weight and height advantage in multi-vehicle accidents (resulting in much fewer deaths in the vehicle, but increasing risks for others) being counterbalanced by their raised center of gravity.
In 2004, the National Highway Traffic Safety Administration released figures showing that drivers of SUVs were 11 percent more likely to die in an accident than people in cars. [1] These figures may be confounded by variables other than the vehicles' inherent safety, for example the documented tendency for SUVs to be driven more recklessly (most sensationally perhaps, the 1996 finding that SUV drivers are more likely to drive drunk [2]). SUV drivers are also statistically less likely to wear their seatbelts. [3]
The considerable weight of full-size SUVs (such as the Chevrolet Suburban and the Ford Excursion) makes collisions with other, smaller cars much less dangerous for the SUV and much more dangerous for the car. The higher ride and other design characteristics of many SUVs may also lead to greater damage to smaller crash partner cars. These mass and design dangers are known as crash incompatibility issues in the crash testing industry, and are a topic of active research. The most notable statistic in SUV design crash incompatibility is an increase in fatalities when an SUV strikes the head of a passenger or driver in a side-impact collision. Template:Uncited This is one of the motivations for the development of side-curtain airbags in standard autos.
The high center of gravity of SUVs makes them more prone to rollover accidents (especially if the vehicle leaves the road or in emergency manoeuvres) than lower vehicles. In recent years, Consumer Reports has found a few SUVs unacceptable due to their rollover risk. This was also dramatically demonstrated in one Fifth Gear show using a Range Rover. Modern SUVs are usually designed to prevent rollovers on flat surfaces. Average heights for:
- Family sedans 57.3 in
- Minivans 70.2 in
- SUVs 70.7 in
SUV safety concerns are compounded by a perception among some consumers that SUVs are safer for their drivers than standard autos. According to G. C. Rapaille, a psychological consultant to automakers (as cited in Gladwell, 2004), many consumers feel safer in SUVs simply because their ride height makes "[their passengers] higher and dominate and look down (sic). That you can look down [on other people] is psychologically a very powerful notion." This and the massive size and weight of SUVs may lead to consumers' false perception of safety (Gladwell, 2004). [4].
In Europe, effective 2006, the fitting of bull bars, also known as grill guards to vehicles such as 4x4s and SUVs is illegal.
Risk to pedestrians
An SUV hitting a pedestrian is about twice as likely to kill as a car at equal speed. Template:Uncited This is in part because the collision of an SUV with a pedestrian tends to impact the chest, while the collision of a car with a pedestrian tends to impact the knees. Template:Uncited
The size and design of SUVs leads to a restricted driver's view of the area immediately surrounding the vehicle. The back view is particularly restricted. Quite a few manufacturers try to remedy the problem by offering rear-view cameras or simple sensors that sound the alarm if the car is about to hit something. This is still rather new technology and is not fool-proof. Aftermarket offerings also exist for interested buyers.
Recent improvements
Manufacturers have added car-level bumpers to reduce the possibility of the other vehicle(s) sliding under the SUV in a collision. SUVs have therefore become somewhat safer for other road users in recent years.
Tax benefits
In the United States, the so-called 'SUV subsidy' (Section 179 depreciation deduction) allows small-business owners to deduct up to $25,000 of the cost of a vehicle with a gross vehicle weight rating of over 6000 lb (2722 kg) from their income tax calculation. Small-business owners may deduct $10,610 of the cost of a passenger automobile. This provides a slight tax incentive for businesses to purchase an SUV. However, the cost of both SUVs and automobiles is fully deductible over future years using normal depreciation. In previous years, this deduction reached $120,000 and was the subject of much criticism.
Fuel economy
The recent popularity of SUVs is one reason the U.S. population consumes more gasoline than in previous years. SUVs are as a class much less fuel efficient than comparable passenger vehicles. The main reason is that SUVs are classified by the U.S. government as light trucks, and thus are subject to the less strict light truck standard under the Corporate Average Fuel Economy (CAFE) regulations. The CAFE requirement for light trucks is an average of 20.7 mpg (US), versus 27.5 mpg (US) for passenger cars (11.4 and 8.6 L/100 km, respectively).
As there is little incentive to change the design, SUVs have numerous fuel-inefficient features. The high profile of SUVs increases wind resistance. Heavier suspensions and larger engines increase vehicle weight. Some SUVs also often come with tires designed for off-road traction rather than low rolling resistance.
The low fuel economy is caused by
- high parasitic masses (compared to the average load) causing high energy demand in transitional operation (in the cities) <math>{P_{accel}= m_{vehicle} \cdot a \cdot v }</math> where P stands for power, <math>m_{vehicle}</math> for the vehicle mass, a for acceleration and v for the vehicle velocity.
- high cross-sectional area causing very high drag losses especially when driven at high speed <math>{F_{drag}= A_{cross} \cdot cw_{vehicle} \cdot \frac {v_{air}^2 \rho_{air}} {2} }</math> where F stands for the force, <math>{A_{cross}}</math> for the cross-sectional area of the vehicle, <math>{\rho_{air}} </math> for the density of the air and <math>{v_{air}}</math> for the relative velocity of the air (incl. wind)
- high rolling resistance due to all-terrain tires (even worse if low pressure is needed offroad) and high vehicle mass driving the rolling resistance <math>{F_{roll}= \mu_{roll} \cdot m_{vehicle} }</math> where <math>{\mu_{roll}}</math> stands for the rolling resistance factor and <math>{m_{vehicle}}</math> for the vehicle mass.
Average data for vehicle types sold in the U.S.A. (source theautochannel.com):
| Type | width | height | curb weight | combined fuel economy |
| SUVs | 73.5in 187cm | 70.7in 180cm | 4242lb 1924kg | 19.19 mpg 12.25 l/100km |
| Minivans | 75.9in 193cm | 70.2in 178cm | 4275lbs 1939kg | 20.36 mpg 11.55 l/100km |
| Family sedans | 70.3in 179cm | 57.3in 146 | 3144lb 1426kg | 26.94 mpg 8.73 l/100km |
| Honda Insight | 66.7in 169cm | 53.3in 135cm | 1850b 839kg | 63 mpg 3.73 l/100km |
Drag resistance for SUVs is at least (same drag coefficient) 30% higher and the acceleration force has to be 35% bigger compared to family sedans. This gives of 40% higher fuel consumptions (even when including parallel hybrid electric SUVs). Template:Uncited
Addressing fuel efficiency, serveral manufacturers now offer hybird gas/electric models of SUVs, offering improved fuel economy over conventionally powered SUVs. With some hybrid SUV models, the added power generated from the hybrid systems is used primarily to give vehicles added performance. Template:Uncited
Weight
The high gross vehicle weight rating of some full-size SUVs (like the Ford Excursion and Hummer H2) technically limits their use on certain roads. Rural bridges often have a 6000 lb (2700 kg) weight limit Template:Uncited, and some full-size SUVs surpass this limit when loaded.Template:Uncited These laws are rarely enforced for SUVs, however, since these vehicles are seen as passenger vehicles instead of commercial trucks.
Handling and braking
Because of the its great weight and high center of mass, an SUV generally performs poorly in emergency manoeuvres. Template:Uncited In braking, the high center of mass directs an excessive loading shift to the front tires, which results in poor traction.
Protests
Anti-SUV vandalism
In April 2005, William Cottrell, a 24-year-old American postgraduate student at Caltech was sentenced to more than eight years in federal prison and $3.5 million in fines for firebombing or vandalizing 125 SUVs at dealerships and a few homes in 2003.[5] Two of his associates fled the country to avoid prosecution. [6]
Slang
In southern England, SUVs, excluding farm vehicles such as Land Rovers, are often referred to in derogatory terms as "Soft-Roaders" or "Chelsea tractors", coined by London Mayor, Ken Livingstone. Template:Citation needed In the UK they are occasionally known as jeeps or Land Rovers no matter what make they actually are, although the increasing prevalence of these vehicles in recent years has decreased this colloquial usage. In New Zealand they are occasionally called "Fendalton tractors" or "Remuera tractors" after the higher priced suburbs in Christchurch and Auckland respectively. In Australia, particularly Victoria, they are referred to as "Toorak Tractors". In The Netherlands they are often called "PC Hooft-tractoren" after Amsterdam's most exclusive shopping street. SUVs are also criticized in the Netherlands for similar reasons, and some environmentalists are pushing local governments to deny SUV users parking spaces.
See also
Notes and references
- Gladwell, M. (2004, January 12). Big and bad. The New Yorker, LXXIX, 28-30. [7]
- Motor Trend. (Complete information on the Motor Trend reference is unavailable. However, the article was Motor Trend's announcement of the Lexus RX 300 as the 1999 SUV of the Year.)
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Additional reading
- Keith Bradsher. High and Mighty: SUVs--The World's Most Dangerous Vehicles and How They Got That Way. Published by PublicAffairs. ISBN 1586482033
- Adam Penenberg. Tragic Indifference : One Man's Battle with the Auto Industry over the Dangers of SUVs. Published by HarperBusiness. ISBN 0060090588
External links
- SUVs actually illegal on many residential roads
- SUVs and oil dependency
- The psychology of SUV purchasing. Includes a comparison of vehicles and their 'deaths inside vehicle' and 'deaths caused/outside of vehicle' rates.
- Information on hybrid SUV'sde:Sports Utility Vehicle
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