UK vehicular history was made last July. For the first time ever the number of diesel vehicles sold outpaced the number of gas powered vehicles sold. Diesel vehicle sales rose to become 50.6% of automobiles sold in the UK in July while gas powered vehicles plummeted by 13.2%.

The diesel engine has made amazing strides in recent years with it becoming consistently clean and efficient compared to its gas counterpart. Point and fact, the Green Car of the Year Award has gone to a diesel powered vehicle (like the Audi A3 TDI pictured above) for the last two years in a row.

A likely cause for the sharp change in buyers preferences has to do with the recession the UK is experiencing. As new car buyers are looking to save in any way possible they are taking note of the impressive efficiency offered from the new lines of diesel cars which often out perform their gas cousins by 15 – 20%.

So the only question remaining is, why haven’t American car buyers caught on to the solid quality offered by modern diesel engines?

According to What Car? Magazine, the diesel Volvo S40 is the greenest car of the year, surprising many as it is a diesel, and not a hybrid, or electric engine. A smaller car with carbon emissions equalling those of the Toyota’s Prius, the Volvo S40 DRIVe received the award from London mayor Boris Johnson.

Johnson said: “There are clear incentives for manufacturers to raise the bar higher and higher to design less gas guzzling cars that take hundreds of pounds off consumers’ fuel bills. This is good for the planet, good for the economy and great for the driver.”

What Car? Magazine editor Steve Fowler said this about the winning car – “It’s not just about a low CO2 figure. The S40 is great to drive, safe, has enough space for the family and, crucially, is cheap to run, too.”

Toyota’s Avensis 2.0 D-4D won the best family car award, while Toyota subsidary Lexus picked up the prize for the greenest 4×4 with a petrol hybrid SUV, the RX450h SE-L.