Category: Small Family 
Price Range: £18,424 to £22,070
Spacious, practical, high driving position, good visibility, quick witted stop/start, economy, huge boot.
Expensive, average to drive, you have to keep your foot on brake to activate the stop/start, dull.
Fuel-saving revisions are welcome, but B-Class continues to trail its competitors on price, drive and ability.
Blue Efficiency is Mercedes' take on Volkswagen's BlueMotion and Ford's Econetic: simple engineering solutions to cut fuel consumption and reduce CO2 without relying on expensive hybrid technology.
This could include improving a car's aerodynamics, reducing rolling resistance and internal friction, introducing weight-saving measures and adding a gearshift indicator and stop/start. The first models in the UK to arrive with the fuel-saving tech are the A-, B- and C-Class models.
Here we drive the B170 petrol that boasts stop/start that reduces fuel consumption by 2.6mpg and 7g/km of CO2. Instead of simply using a starter motor to re-start the B-Class, Mercedes has employed a more sophisticated starter generator that uses a belt connected to the crankshaft. This promises quicker and smoother re-starts. Better still, when not in use the system transforms into a generator powering the cars electronics. This alone, says the firm, yields fuel savings of up to 9%.
The B-Class doesn't come cheap though, especially when the B170 we tested came in the range-topping Sport trim. However, with big 17" rim and a subtle but sporty bodykit at least it proves you don't have to be boring to go green.
So, is this Mercedes really as green as it implies and how does it compare with rivals? Read on to find out.
