The Smart Fortwo was found to be the most fuel efficient two-seater car by the United States Environmental Protection Agency's (EPA) 2008 Fuel Economy Guide. It offers a fuel efficiency of 7.1 L/100 km in the city and 5.7 L/100 km on the highway.
The Fortwo has just an overall length of 2.69 meter and the amazing part is that it has very less CO2 emissions (119 grams/km).