Safety

SUV's are built with higher ground clearance for off-road use and thus have a higher center of gravity,^[4] 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 cause the bottom of the vehicle to move away and out from under the vehicle during a turn.

Pickups and SUVs are more likely to be in rollover accidents than passenger cars. According to a study conducted in the United States, pickups have twice the fatality rate of cars and SUVs have nearly triple the fatality rate in rollover accidents.^[5] Of vehicles 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 the passenger cars.^[5]

Environment

In the United States, the number of ORV users since 1972 has climbed sevenfold—from five million to 36 million in 2000.^[6] Government policies that protect wilderness but also allow recreational ORV use have been the subject of some debate within the United States and other countries.^[7]

All trail and off-trail activities impact natural vegetation and wildlife, which can lead to erosion, invasive species, habitat loss, and ultimately species loss^[8][9][10] decreasing anecosystem's ability to maintain homeostasis.^[11] ORV's 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 then those who follow legal trails.^[12][13] Illegal use of off-road vehicles has been identified as a serious land management problem ranked with dumping garbage and other forms of vandalism.^[14] Many user organizations, such as Tread Lightly! and the Sierra Club, publish and encourage appropriate trail ethics.^[15]

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,^[16] 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 ground water."^[17][18] 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."^[19][20]

• Off Road Vehicle Erosion
• 

  Negative environmental effects caused by a motorcycle to a portion of the Los Padres National Forest.
 
• 

  Negative environmental effects that occurred when off-road vehicle drivers deliberately left the posted trail. Anza-Borrego Desert State Park.