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An off-road vehicle (ORV), sometimes referred to as an off-highway vehicle (ORV), overland vehicle, or adventure vehicle, is any type of vehicle designed to drive off road on non-paved surfaces, [1] such as trails and forest roads, which that have rough, uneven, and low-traction surfaces.
One of the first modified off-road vehicles was the Kégresse track, a conversion undertaken first by Adolphe Kégresse, who designed the original while working for Czar Nicholas II of Russia, between 1906 and 1916. [2] The system uses a caterpillar track with a flexible belt rather than interlocking metal segments. It can be fitted to a conventional car or truck to turn it into a half-track, suitable for use over rough or soft ground.
After the Russian Revolution of 1917, Kégresse returned to his native France where the system was used on Citroën cars between 1921 and 1937 for off-road and military vehicles. The Citroën company sponsored several overland expeditions with their vehicles crossing North Africa and Central Asia.
A huge wheeled vehicle designed from 1937 to 1939 under the direction of Thomas Poulter called Antarctic Snow Cruiser, was intended to facilitate transport in Antarctica. While having several innovative features, it generally failed to operate as hoped under the difficult conditions, and was eventually abandoned in Antarctica.
The U.S. Jeep Wagoneer and the Ford Bronco, the British Range Rover, and the station wagon-bodied Japanese Toyota Land Cruiser, Nissan Patrol, and Suzuki Lj's series were all essentially just station wagon bodies on light truck frames with four-wheel-drive drivetrains. Later, during the 1990s, manufacturers started to add even more luxuries to bring those off-road vehicles on par with regular cars. This eventually evolved into what we call the SUV today. It also evolved into the newer crossover vehicle, where utility and off-road capability were sacrificed for better on-road handling and luxury.
To be able to drive off the pavement, off-road vehicles need several characteristics: They need to have a low ground pressure, so as not to sink into soft ground, they need a lot of ground clearance, to not get stuck on obstacles, and they need to keep their wheels or tracks on the ground, so as not to lose traction. Wheeled vehicles accomplish this by having a suitable balance of large or additional tires, combined with tall and flexible suspension. Tracked vehicles accomplish this by having wide tracks and a flexible suspension on the road wheels.
![Russian GAZ-34039 [ru] GT-SM at Vankorskoe oilfield.jpg](http://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/%D0%93%D0%A2-%D0%A1%D0%9C_at_Vankorskoe_oilfield.jpg/220px-%D0%93%D0%A2-%D0%A1%D0%9C_at_Vankorskoe_oilfield.jpg)
The choice of wheels versus tracks is one of cost and suitability. A tracked drivetrain is more expensive to produce and maintain. Wheeled drivetrains are cheaper and give a higher top speed. A tracked drivetrain has greater off-road capability.
Tires play a significant role for any off-road vehicle equipped with wheels, as they ensure optimal traction required to keep it moving. The off-road tire tread types vary depending on the terrain type. The most common types of off-road tires are A/T (stands for "All Terrain") and M/T (stands for "Mud Terrain"). While the A/T tires perform excellently on the sand, they are barely usable in the mud. There are also unique Sand Blaster and Mud bogging tires used for the most challenging terrains such as dirt, sand, and even water to maintain traction at extreme angles and high speeds (off-road motorsport). [3]
Most off-road vehicles are fitted with especially low gearing. This allows the operator to make the most of the engine's available power while moving slowly through challenging terrain. An internal combustion engine coupled to a standard gearbox often has an output speed too high. The vehicle often has one of two things, either a very low ("granny") first gear (like the all-wheel drive Volkswagen Transporter versions) or an additional gearbox in line with the first, called a reduction drive. Some vehicles, like the Bv206 in the picture on the right, also have torque converters to further reduce the gearing. [4]
SUVs are built with higher ground clearance, for off-road use, and thus have a higher centre of gravity, [5] therefore increasing the risk of rollover. When an SUV turns, the vehicle's mass resists the turn and carries the weight forward, thus allowing the traction from the tires to create a lateral centripetal force as the vehicle continues through the turn. The conflict between the top weight of the SUV's desire to go straight while the friction of the tires on the road causes the bottom of the vehicle to move away and out from under the vehicle during a turn.
SUVs are more likely to be in rollover accidents than passenger cars. According to a study conducted in the United States, SUVs have twice the fatality rate of cars and have nearly triple the fatality rate in rollover accidents. [6]
In the United States, light trucks (including SUVs) represent 36 percent of all registered vehicles. They are involved in about half of the fatal two-vehicle crashes with passenger cars, and 80 percent of these fatalities are to occupants of passenger cars. [6]
In the United States, the number of ORV users since 1972 has climbed sevenfold—from five million to 36 million in 2000. [7] Government policies that protect wilderness but also allow recreational ORVs, have been the subject of some debate within the United States and other countries. [8]
All trail and off-trail activities impact natural vegetation and wildlife, which can lead to erosion, invasive species, habitat loss, and ultimately, species loss [9] [10] [11] decreasing an ecosystem's ability to maintain homeostasis. [12] ORVs cause greater stress to the environment than foot traffic alone, and ORV operators who attempt to test their vehicles against natural obstacles can do significantly more damage than those who follow legal trails. [13] [14] Illegal use of off-road vehicles has been identified as a serious land management problem ranked with dumping garbage and other forms of vandalism. [15] Many user organizations, such as Tread Lightly! and the Sierra Club, publish and encourage appropriate trail ethics. [16]
ORVs have also been criticized for producing more pollution in areas that might normally have none. In addition to noise pollution that can cause hearing impairment and stress in wildlife, [17] according to the U.S. Forest Service, old-style two-stroke engines (no longer a component of new off-road vehicles, although some are still in use) "emit about 20 to 33 percent of the consumed fuel through the exhaust" and "discharge from two-stroke snowmobile engines can lead to indirect pollutant deposition into the top layer of snow and subsequently into the associated surface and groundwater." [18] [19] In 2002, the United States Environmental Protection Agency adopted emissions standards for all-terrain vehicles that "when fully implemented in 2012... are expected to prevent the release of more than two million tons of air pollution each year—the equivalent of removing the pollution from more than 32 million cars every year." [20] [21]
Common[ where? ] commercial vehicles used for off-roading include four-wheel-drive pickup trucks and SUVs such as the Ford F-Series, Jeep Wrangler, and Toyota Land Cruiser, among others. Typically, owners will perform additional modifications to the wheels, tires, suspension, and body in order to improve their performance off-road. A number of decommissioned military vehicles have also seen civilian use, including the Jeep CJ and the AM General Hummer. Some, like the early Land Rovers, were adapted to military use from civilian specifications. Specialized off-road vehicles include Utility terrain vehicles (UTVs), All-terrain vehicles (ATVs), dirt bikes, dune buggies, rock crawlers, and sandrails.
An all-terrain vehicle (ATV), also known as a light utility vehicle (LUV), [22] a quad bike or quad (if it has four wheels), as defined by the American National Standards Institute (ANSI), is a vehicle that travels on low-pressure tires, has a seat that is straddled by the operator, and has handlebars. As the name implies, it is designed to handle a wider variety of terrain than most other vehicles. It is street-legal in some countries, but not in most states, territories and provinces of Australia, the United States, and Canada.
By the current ANSI definition, ATVs are intended for use by a single operator, but some ATVs, referred to as tandem ATVs, have been developed for use by the driver and one passenger. [23]
The rider sits on and operates these vehicles like a motorcycle, but the extra wheels give more stability at slower speeds. Although most are equipped with three or four wheels, six or eight wheel (tracked) models exist and existed historically [24] for specialized applications. Multiple-user analogues with side-by-side seating are called utility terrain vehicles (UTVs) or side-by-sides to distinguish the classes of vehicle. Both classes tend to have similar powertrain parts. Engine sizes of ATVs for sale in the United States as of 2008 ranged from 49 to 1,000 cc (3.0 to 61 cu in).The military market for off-road vehicles used to be large, but, since the fall of the Iron Curtain in the 1990s, it has dried up to some extent. The U.S. jeeps, developed during World War II, coined the word many people use for any type of light off-road vehicle. In the U.S., the Jeeps' successor from the mid-1980s was the AM General HMMWV series. The Red Army used the GAZ-61 and GAZ-64 during World War II. The Eastern Bloc used the GAZ-69 and UAZ-469 in similar roles.
Vehicles used as the primary transport in an expedition, not for profit, scientific research or personal use.
A sport utility vehicle (SUV) is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive.
An all-terrain vehicle (ATV), also known as a light utility vehicle (LUV), a quad bike or quad, as defined by the American National Standards Institute (ANSI), is a vehicle that travels on low-pressure tires, has a seat that is straddled by the operator, and has handlebars. As the name implies, it is designed to handle a wider variety of terrain than most other vehicles. It is street-legal in some countries, but not in most states, territories and provinces of Australia, the United States, and Canada.
A four-wheel drive, also called 4×4 or 4WD, is a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case providing an additional output drive shaft and, in many instances, additional gear ranges.
The Ford Explorer is a range of SUVs manufactured by Ford Motor Company since the 1991 model year. The first five-door SUV produced by Ford, the Explorer was introduced as a replacement for the three-door Bronco II. As with the Ford Ranger, the model line derives its name from a trim package previously offered on Ford F-Series pickup trucks. As of 2020, the Explorer became the best-selling SUV of all time in the American market.
A locking differential is a mechanical component, commonly used in vehicles, designed to overcome the chief limitation of a standard open differential by essentially "locking" both wheels on an axle together as if on a common shaft. This forces both wheels to turn in unison, regardless of the traction available to either wheel individually.
Off-roading is the act of driving or riding in a vehicle on unpaved surfaces such as sand, dirt, gravel, riverbeds, mud, snow, rocks, or other natural terrain. Off-roading ranges from casual drives with regular vehicles to competitive events with customized vehicles and skilled drivers.
A rollover or overturn is a type of vehicle crash in which a vehicle tips over onto its side or roof. Rollovers have a higher fatality rate than other types of vehicle collisions.
The Toyota 4Runner is an SUV manufactured by the Japanese automaker Toyota and marketed globally since 1984, across six generations. In Japan, it was marketed as the Toyota Hilux Surf and was withdrawn from the market in 2009. The original 4Runner was a compact SUV and little more than a Toyota Hilux pickup truck with a fiberglass shell over the bed, but the model has since undergone significant independent development into a cross between a compact and a mid-size SUV. All 4Runners have been built in Japan at Toyota's plant in Tahara, Aichi, or at the Hino Motors plant in Hamura.
The Ford Bronco is a model line of SUVs manufactured and marketed by Ford. The first SUV model developed by the company, five generations of the Bronco were sold from the 1966 to 1996 model years. A sixth generation of the model line was introduced for the 2021 model year. The nameplate has been used on other Ford SUVs, namely the 1984–1990 Bronco II compact SUV and the 2021 Bronco Sport compact crossover.
The AMC Eagle is a compact four-wheel drive passenger vehicle manufactured and marketed in a single generation by American Motors Corporation (AMC) for model years 1980 through 1987 and continued by Chrysler Corporation following its acquisition of AMC in 1987, for the 1988 model year.
A drive wheel is a wheel of a motor vehicle that transmits force, transforming torque into tractive force from the tires to the road, causing the vehicle to move. The powertrain delivers enough torque to the wheel to overcome stationary forces, resulting in the vehicle moving forwards or backwards.
A beadlock or bead lock is a mechanical device that secures the bead of a tire to the wheel of a vehicle. Tires and wheels are designed so that when the tire is inflated, the tire pressure pushes the bead of the tire against the inside of the wheel rim so that the tire stays on the wheel and the two rotate together. In situations where tire pressure is insufficient to hold the bead of the tire in place, a beadlock is needed.
Six-wheel drive is an all-wheel drive drivetrain configuration of three axles with at least two wheels on each axle capable of being driven simultaneously by the vehicle's engine. Unlike four-wheel drive drivetrains, the configuration is largely confined to heavy-duty off-road and military vehicles, such as all-terrain vehicles, armored vehicles, and prime movers.
A beam axle, rigid axle, or solid axle is a dependent suspension design in which a set of wheels is connected laterally by a single beam or shaft. Beam axles were once commonly used at the rear wheels of a vehicle, but historically, they have also been used as front axles in four-wheel-drive vehicles. In most automobiles, beam axles have been replaced with front (IFS) and rear independent suspensions (IRS).
The Jeep Patriot (MK74) is a front-engine five-door compact crossover SUV manufactured and marketed by Jeep, having debuted with the Jeep Compass in April 2006 at the New York Auto Show for the 2007 model year. Both cars, as well as the Dodge Caliber, shared the GS platform, differentiated by their styling and marketing, with the Patriot exclusively offering a four-wheel drive system, marketed as Freedom Drive II.
An amphibious all-terrain vehicle, or amphibious ATV, is a small, all-wheel drive, all-terrain amphibious vehicle, used for recreation, farm-, hunting, utility or industry tasks, by enthusiasts and professionals worldwide. They are legally off-highway vehicles in many countries, or at least restricted from use on express highways and motorways – their use is generally extra-urban.
In automotive design, an F4, or front-engine, four-wheel drive (4WD) layout places the internal combustion engine at the front of the vehicle and drives all four roadwheels. This layout is typically chosen for better control on many surfaces, and is an important part of rally racing, as well as off-road driving. In terms of racing purposes, whether it be on-road or off-road, can be described as follows,
A team that pursues the Weak LS4WD architecture will minimize the development cost of the front-wheel drive system at the expense of having a larger rear powertrain. The Weak architecture produces a vehicle with a large powersplit between the front and rear powertrains, while the Strong architecture recommends a vehicle with more similar power and torque requirements for the front and rear.
Eight-wheel drive, often notated as 8WD or 8×8, is a drivetrain configuration that allows all eight wheels of an eight-wheeled vehicle to be drive wheels simultaneously. Unlike four-wheel drive drivetrains, the configuration is largely confined to heavy-duty off-road and military vehicles, such as armored vehicles, tractor units or all-terrain vehicles such as the Argo Avenger.
A side-by-side vehicle, is an off-road vehicle with a minimum of two seats positioned side by side and enclosed within a roll cage structure. They have a minimum of four wheels and are operated by foot controls and a steering wheel. Depending on use and application they can also be called a utility task vehicle, utility terrain vehicle (UTV), recreational off-highway vehicle (ROV), or multipurpose off-highway utility vehicle (MOHUV).
The Jeep Liberty (KJ), or Jeep Cherokee (KJ) outside North America, is a compact SUV that was produced by Jeep from 2002 to 2007. Introduced in May 2001 as a replacement for the Cherokee (XJ), the unibody Liberty was priced between the Wrangler and Grand Cherokee. It was the smallest of the 4-door Jeep SUVs up until the car platform based 4-door Compass and Patriot arrived for 2007.
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Media related to Off-road vehicles at Wikimedia Commons
