as a company car driver... yes.
Tax is now done on the CO2 emissions.
Wouldnt you say though that you care about tax, not the CO2 emissions. If you had 2 identical cars side by side, one costs £150 a year to tax and the other £200, you would get the £150. You would look at the tax costs first, with the CO2 emissions just a number on the specs page.
I know its kind of swings and roundabouts, low emissions = low tax. What Im getting at is that (most) people are driven (unintentional pun) by the running costs. If for some bizarre reason a car with twice the emissions costs half the tax of another car, and got more MPG (somehow) people wouldnt even consider the car with the better CO2 emissions. Same way Id imagine if a fuel came out that was particularly nasty, say it ran on the blood of puppies and kittens, but was half the price of petrol, I am guessing a lot of people would use it and be damned with the puppies and kittens.