Audi A6 TDI
Proving that diesel is no longer a dirty word, the Audi A6 can travel 700 highway miles (1126 km) on a single tank and a fuel efficiency of 38mpg (7.4 liters per 100 km) on the combined cycle. Yet, it can still accelerate from 0-62mph (100km/h) in just 5.5 seconds
It shares many of the underpinnings found in the latest-generation Ford Focus but the Mazda 3 stands out when it comes to fuel economy. Thanks to its new SKYACTIV technology and the use of a capacitor-based regenerative engine braking system, even the 2.5-liter model is capable of averaging 38mpg (7.4 liters per 100 km).
In Europe, the company has carved out a reputation for excellent, smooth, efficient yet surprisingly potent diesel engines but what makes the 328d different is that it only has four cylinders (BMW favors six cylinder powerplants). Thanks to engine auto start-stop technology and a regenerative braking system so that fuel isn't used for recharging the battery, the car is capable of 45mpg (6.3 liters per 100 km) on the highway.
Unlike its German competitors, the Accord can be specified with a choice of traditional and hybrid engines but even its thirstiest, V6 engine is capable of a remarkable 34mpg. The Hybrid version returns 50mpg (5.6 liters per 100 km) around the city (47mpg on the highway) and the plug-in hybrid version a very impressive 115mpg (2.5 liters per 100 km) on the combined cycle, making it the most frugal plug-in hybrid currently available in the US.
The 2014 Corolla pairs a very economic engine (1.8-liters, 140 horsepower) with an electronic management system that automatically adjusts acceleration and the drain of on-board systems on the battery and engine. The result is 42 highway mpg (6.7 liters per 100 km). Yet despite this technological meddling, the car somehow remains fun to drive.