Cars

-Residents of low-density, residential-only sprawling communities are also more likely to die in car collisions[original research'] which kill 1.2 million people worldwide each year, and injure about forty times this number. -[20] Sprawl is more broadly a factor in inactivity and obesity, which in turn can lead to increased risk of a variety of diseases.[ -Sports cars go way too fast. Environmental impact See also: automobile emissions  Transportation is a major contributor to air pollution in most industrialised nations. According to the American Surface Transportation Policy Project nearly half of all Americans are breathing unhealthy air. Their study showed air quality in dozens of metropolitan areas has worsened over the last decade.[27] In the United States the average passenger car emits 11,450 lbs (5 tonnes) of carbon dioxide, along with smaller amounts of carbon monoxide, hydrocarbons, and nitrogen.[28] Animals and plants are often negatively impacted by automobiles via habitat destruction and pollution. Over the lifetime of the average automobile the "loss of habitat potential" may be over 50,000 square meters (538,195 square feet) based on Primary production correlations.[29] Fuel taxes may act as an incentive for the production of more efficient, hence less polluting, car designs (e.g. hybrid vehicles) and the development of alternative fuels. High fuel taxes may provide a strong incentive for consumers to purchase lighter, smaller, more fuel-efficient cars, or to not drive. On average, today's automobiles are about 75 percent recyclable, and using recycled steel helps reduce energy use and pollution.[30] In the United States Congress, federally mandated fuel efficiency standards have been debated regularly, passenger car standards have not risen above the 27.5 miles per US gallon (8.55 L/100 km; 33.0 mpg-imp) standard set in 1985. Light truck standards have changed more frequently, and were set at 22.2 miles per US gallon (10.6 L/100 km; 26.7 mpg-imp) in 2007.[31] Alternative fuel vehicles are another option that is less polluting than conventional petroleum powered vehicles. Alternatives to the automobile Main article: Alternatives to the automobile Established alternatives for some aspects of automobile use include public transit (buses, trolleybuses, trains, subways, monorails, tramways), cycling, walking, rollerblading, skateboarding, horseback riding and using a velomobile. Car-share arrangements and carpooling are also increasingly popular–the U.S. market leader in car-sharing has experienced double-digit growth in revenue and membership growth between 2006 and 2007, offering a service that enables urban residents to "share" a vehicle rather than own a car in already congested neighborhoods.[40] Bike-share systems have been tried in some European cities, including Copenhagen and Amsterdam. Similar programs have been experimented with in a number of U.S. Cities.[41] Additional individual modes of transport, such as personal rapid transit could serve as an alternative to automobiles if they prove to be socially accepted.[42]  The examples and perspective in this section may not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (June 2010)