Back in 2002, Volkswagen
unveiled its concept for a super-efficient one-liter car. The prototype, now dubbed the XL1, has been in development ever since, but now appears to be edging closer to production. Spotted undergoing hot-weather testing by our trusty spy photographers, the 235-mpg prototype packs an 800cc two-cylinder turbo diesel injection engine delivering some 50 horsepower and 88 lb-ft of torque, paired to a 30 hp electric motor. Both engines channel their power to the rear wheels via a 7-speed DSG transmission.