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Off-road vehicle

From Wikipedia, the free encyclopedia
Not to be confused with Sport utility vehicle (SUV).
Mercedes-Benz Unimog in the Dunes of Erg Chebbi in Morocco. The vehicle's portal gear axles provide high ground clearance.

An off-road vehicle (ORV), sometimes referred to as an off-highway vehicle (ORV), overland vehicle, or adventure vehicle, is any vehicle designed to drive off-road on non-paved surfaces,[1] such as trails and forest roads, that have rough, uneven, and low-traction surfaces. Off-road vehicles have been popularized through competitive off-road events, such as the annual Dakar Rally,[2] which challenges vehicles to navigate harsh terrain across various countries.

History

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Nicholas II's Packard Twin-6 with Kégresse track, 1917

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.[3] 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 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 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 added 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.

Technical details

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Swedish Hägglunds Bv206 with wide rubber tracks

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 flexible suspension on the road wheels.

Russian GAZ-34039 [ru]

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, ensuring optimal traction 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).[4]

Most off-road vehicles are fitted with low gearing. This allows the operator to optimize 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 reduce the gearing.[5]

Criticism

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Safety

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Main article: Criticism of sport utility vehicles

SUVs are built with higher ground clearance, for off-road use, and thus have a higher center of gravity,[6] therefore increasing the risk of rollover. When an SUV turns, the vehicle's mass resists the turn. This carries the SUV's 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 and the friction of the tires on the road causes the bottom of the vehicle to move away and out from under the SUV 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 passenger cars and have nearly triple the fatality rate in rollover accidents.[7]

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.[7]

Environment

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In the United States, the number of ORV users since 1972 has climbed sevenfold—from five million to 36 million in 2000.[8] Government policies that protect wilderness but also allow recreational ORVs, have been the subject of some debate within the United States and other countries.[9]

All trail and off-trail activities impact natural vegetation and wildlife, which can lead to erosion, invasive species, habitat loss, and ultimately, species loss[10][11][12] decreasing an ecosystem's ability to maintain homeostasis.[13] 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.[14][15] Illegal use of off-road vehicles has been identified as a serious land management problem ranked with dumping garbage and other forms of vandalism.[16] Many user organizations, such as Tread Lightly! and the Sierra Club, publish and encourage appropriate trail ethics.[17]

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,[18] 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."[19][20] 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."[21][22]

Civilian use

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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 to improve their performance off-road. Several decommissioned military vehicles have also been used by civilians, 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.

All-terrain vehicle

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This section is an excerpt from All-terrain vehicle.[edit]
The ATV is commonly called a four-wheeler in Australia, South Africa, parts of Canada, India, and the United States. They are used extensively in agriculture, because of their speed and light footprint.

An all-terrain vehicle (ATV), also known as a light utility vehicle (LUV),[23] 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.[24]

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[25] 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).

Other applications

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Military vehicle

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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 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.

Experimental vehicle

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  • Experimental marsh buggy, 1928, stuck in mud.
    Experimental marsh buggy, 1928, stuck in mud.

Commercial vehicle

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  • Off-road bus in Iceland.
    Off-road bus in Iceland.

Scientific vehicle

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Expedition vehicle

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Vehicles used as the primary transport in an expedition, not for profit, scientific research or personal use.

See also

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References

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Notes

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  1. ^ "Off-Road Vehicle Act" (Web). New Brunswick Acts and regulations. Attorney General, New Brunswick, Canada. June 27, 1985. Retrieved 2007-10-17.
  2. ^ "Dakar Rally". Retrieved 2024-11-08.
  3. ^ MiG-registeret
  4. ^ "Mud terrain vs all-terrain tires – pros, cons & comparison". offroadium.com. Retrieved 2017-04-17.
  5. ^ https://pioneerrentals.ca/wp-content/uploads/2019/04/Hagglund_BV206D6_en.pdf [bare URL PDF]
  6. ^ Rodney E. Slater (U.S. Transportation Secretary) (April 9, 1998). "Secretary Slater Proposes New Label; Warning of Rollover Danger for Sport Utility Vehicles". News Release. National Highway Traffic Safety Administration. Archived from the original (Web) on 2007-02-13. Retrieved 2007-05-17.
  7. ^ a b Jeffrey W. Runge, M.D. (Administrator, National Highway Traffic Safety Administration) (February 26, 2003). "The Honorable Jeffrey W. Runge, M.D. Administrator National Highway Traffic Safety Administration Before the Committee on Commerce, Science, and Transportation United States Senate" (Web). Testimony before the Committee on Commerce, Science, And Transportation, United States Senate. National Highway Traffic Safety Administration. Retrieved 2007-05-17.{{cite web}}: CS1 maint: multiple names: authors list (link)
  8. ^ "Forest Service Rule Revs Up Off-Road Vehicle Fight" (Web). Article. Environment News Service (ENS). July 8, 2004. Retrieved 2007-06-24.
  9. ^ van Wagtendonk, Jan W. (2003). "Role of Science in Sustainable Management of Yosemite Wilderness" (PDF). USDA Forest Service Proceedings RMRS-P-27. 2003. USDA Forest Service. Retrieved 2007-06-24.
  10. ^ Rice, Kathleen C. "National Collection of Imperiled Plants – Pholisma sonorae". Center for Plant Conservation. Retrieved 8 June 2012.
  11. ^ "Mojave lizard may get protection; off-road vehicles are cited as threat". Los Angeles Times. 12 January 2008. Retrieved 2 May 2015.
  12. ^ "Officials seek to protect desert reptile". Las Vegas Review-Journal. Retrieved 2 May 2015.
  13. ^ "Technical Notes" (PDF). Conserving Natural and Cultural Resources on Department of Defense Lands; Case Studies from the DoD Conservation Program (Page 13). US Department of Defense. 2004. Archived from the original (PDF) on 2007-06-28. Retrieved 2007-06-24.
  14. ^ Kristine Sowl & Rick Poetter (April 16, 2004). "Impact Analysis of Off-Road Vehicle Use for Subsistence Purposes on Refuge: Lands and Resources Adjacent to the King Cove Access Project" (PDF). Izembek National Wildlife Refuge (page 6). US Fish and wildlife services Alaska. Archived from the original (PDF) on 2007-06-28. Retrieved 2007-06-24.
  15. ^ "Recreation Management Goals and Strategies" (PDF). Capitol State Forest Recreation and Public Use Plan—Part II (Page 45). Washington State Department of Natural Resources. Archived from the original (PDF) on 2007-02-21. Retrieved 2007-06-24.
  16. ^ "Chapter 11. Field Management Status" (Web). Land Management (11.5.2 Identified Concerns of the Parks Department). Central Pine Barrens Joint Planning and Policy Commission. Retrieved 2007-06-24.
  17. ^ "Codes of Ethics Advocated by Groups Outside of Ontario" (Web). Trail Ethics. Trent University. January 16, 2007. Retrieved 2007-06-24.
  18. ^ "The Impacts of Off-Road Vehicle Noise on Wildlife". Archived from the original on 2010-12-25. Retrieved 2009-01-19.
  19. ^ "Chugach National Forest – Home" (PDF). Retrieved 2 May 2015.
  20. ^ "Addressing the Ecological Effects of Off-Road Vehicles". Archived from the original on 2008-11-28. Retrieved 2009-01-19.
  21. ^ "New Air Pollution Rules Target Off-Road Vehicles" (Web). Article. Environment News Service (ENS). September 17, 2002. Retrieved 2007-06-24.
  22. ^ "Final Rule for Cleaner Large Industrial Spark-Ignition Engines, Recreational Marine Diesel Engines, and Recreational Vehicles" (Web). US Environmental Protection Agency. March 6, 2006. Retrieved 2007-06-24.
  23. ^ "24556 Demonstrate knowledge of the safe operation of a light utility vehicle (LUV)" (PDF). NZQA. 2019.
  24. ^ "Standards for All Terrain Vehicles and Ban of Three-Wheeled All Terrain Vehicles; Proposed Rule". Consumer Product Safety Commission (Federal Register). 10 August 2006. Archived from the original on 13 January 2008. Retrieved 26 December 2007.
  25. ^ "How Many Wheels Did The Original ATV Have? – ATV Trail Reviews". 24 August 2021. Retrieved 2022-02-22.

Bibliography

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  • Allen, Jim; Weber, James J. (2021). The Four-Wheeler's Bible: The Complete Guide to Off-Road and Overland Adventure Driving (3rd ed.). Beverly, MA, USA: Motorbooks. ISBN 9780760368053.
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Media related to Off-road vehicles at Wikimedia Commons

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