The world’s most fuel-efficient hybrid car, the Volkswagen XL1. The design brief for the XL1 was to produce a ‘one litre’ car – that is to say, a car that uses one litre of fuel per 100 km, equivalent to 282 miles per gallon. The resulting vehicle uses just 0.9 litres per 100 km, or 313 mpg, and this high mpg figure correlates to a very low carbon dioxide emissions value of just 21 g/km. To achieve this fuel consumption figure, the XL1 was aerodynamically optimised, adopting the classic ‘tear drop’ shape and utilising innovations such as removing traditional wing mirrors and replacing them with small cameras called e-Mirrors which transmit exterior images to interior displays. With a drag coefficient of 0.189 the XL1 can maintain 100 kmh on a level road in still air using just 8.4 PS.