Volkswagen installed software on 482,000 diesel vehicles sold in the US between 2008-2015 to trick emissions tests. The software could detect when the car was being tested and turned on full emissions controls, but turned them off during normal driving to improve performance and fuel economy. VW admitted nearly 11 million worldwide vehicles were fitted with similar "defeat devices", emitting nitrogen oxide levels up to 40 times the legal limit. US authorities can fine VW up to $37,500 per affected vehicle, totaling $18 billion. The scandal is a major setback that will severely damage Volkswagen's reputation.