Blonde Girl Strips Her Short Jeans Near The Yamaha All-terrain Vehicle

ATVs accounted for 58% of the SI (spark ignited) recreational vehicles in the US in the year 2000. That year, recreational SI vehicles produced 0.16% of NOx, 8% of HC, 5% of CO and .8% of PM emissions for all vehicles, both highway and nonroad. As a point of comparison, the nonroad SI < 19 kW (~25 hp) category (small spark ignition engines such as lawnmowers) comprised 20% of HC and 23% of CO total emissions. While recreational SI vehicles produce an aggregate of <4% of all HC emissions in the US, based on the relatively small population of ATVs (<1.2M) and small annual usage (<350 hrs), EPA emission regulations now include such engines, starting with the model year 2006. Engines meeting these standards now produce only 3% of the HC emissions that previously unregulated engines did.
Land usage
In some countries where fencing is not common, such as the US, Canada and Australia, a huge percentage of ATV riders knowingly cross privately owned property in rural areas and travel over public/private properties, where their use is explicitly limited to trails. Subsequently, environmentalists criticize ATV riding as a sport for excessive use in areas biologists consider to be sensitive, especially wetlands and sand dunes and in much of inland Australia.