The greenest saloon in Britain is a BMW

How to test the real-world fuel economy of a car? Why, throw it into the real world. Which, for me, means driving up and down the motorway for hours on end.

Which is exactly what I did in a BMW 320d EfficientDynamics recently. The fact I was on a deadline meant I didn’t do my usual eco-monitoring. I simply reset the trip computer and then turned the display off, choosing instead to display the sat nav’s ETA in the dash display. Every minute counts and all that.

Curiosity got the better of me. By journey’s end, I checked the mpg. 63.

The next day, I was on another deadline, so again didn’t do any fuel monitoring. This time, despite taking in the UK’s highest motorway, the results were again eye-opening: 72.9mpg. 

Which, for those who know me, meant only one thing. The next day would be economy run day. Up particularly early I got, turned off the air con, set the 3er into Eco Pro fuel-saving mode and gingerly crept towards the M6.

As previously explained, this doesn’t mean driving at a dangerously slow speed. Rather, it simply means driving with the trucks, at around 50-55mph, instead of the usual 80mph British motorway cruising gait. Drive in the inside lane instead of the middle: couldn’t be simpler.

My trip to the office is representative: it’s 100 miles, mainly of motorway but also including urban driving and fastish A-road motoring. Two hours later, I’d added about 10-15mins to the journey time, and had what’s called A Result:

Yup, 90.2mpg. From a 163hp 2.0-litre turbodiesel that will also (albeit not at the same time) do 143mph and hit 60mph from rest in 8.0 seconds.

I was absolutely speechless. I knew how I’d driven, understood that I hadn’t done anything particularly clever or eco-fanatical – knew I’d been safe and had simply accepted that trucks would be my train rather than the usual commuter fare. Yet the result had been the second-best fuel consumption figure I’d ever recorded.

The CO2 equivalent for that journey was less than 80g/km. OK, there’s a margin of error in the trip computer reading, but even so: have you ever seen such a high mpg reading, over such a long journey, in such an otherwise conventional car?

Which, of course, is great news for LOCOG, whose intention is to be the greenest and most sustainable Olympic Games ever. Because 1,500 BMW 320d are, right now, being used as shuttle cars for Olympics organisers…

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First Drive: BMW 3 Series (F30)

Twin Test: Audi A4 v BMW 3 Series

MSN long term test: VW Golf Bluemotion

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