When we first reported Audi was going to attempt the efficiency marathon, we never doubted they would achieve their goal. With 20 randomly selected readers of a motoring magazine and a team of two from Audi, all eleven A4 models completed the 1,650 km journey from Basel, Switzerland to Vienna, Austria and back on one tank of fuel.

As a result, the best performing vehicle achieved fuel consumption average of 3.32 liters per 100km (70.85 US mpg) while the “worst” achieved 3.50 l/100km (67.20 US mpg), far exceeding the vehicle's official specification of 4.1 liters (57.37 US mpg).

After a total driving time of 22 hours with an average speed of between 73 and 80 km/h (45.36 and 49.71 mph), the winning team surprisingly had a higher average speed of 81.4 km/h (50.58 mph) than the others.

With the amount of fuel that remained after the trip, it would even have been possible to cover a distance of over 2,000 kilometers (1242.74 miles) or the air conditioning system could have been switched on.

Audi Surpasses Expectation in Fuel Consumption Efficiency Marathon