<P> Transportation (of all types including trucks, buses and cars) 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 . </P> <P> Animals and plants are often negatively impacted by cars via habitat destruction and pollution . Over the lifetime of the average car the "loss of habitat potential" may be over 50,000 m (540,000 sq ft) based on primary production correlations . Animals are also killed every year on roads by cars, referred to as roadkill . More recent road developments are including significant environmental mitigations in their designs such as green bridges to allow wildlife crossings, and creating wildlife corridors . </P> <P> Growth in the popularity of vehicles and commuting has led to traffic congestion . Brussels was considered Europe's most congested city in 2011 according to TomTom . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2010) (Learn how and when to remove this template message) </Td> </Tr> </Table>

When was the first gas powered car made