I have a confession to make. Today we took receipt of a new car (well, new to us). And it doesn't replace our existing estate, so that takes us back to being a 2-car family.It's certainly painful to the wallet, particularly the insurance costs as it'll be used a bit by the kids when they're confident enough with their driving. (No way we were going to have them driving the bulky and large-engined estate.) But I can't decide if it's good or bad news to the environment.It's a 1.2 litre compact, that's only 4 years old, so I'd hope it's emissions aren't too bad. And being very light I hope the fuel efficiency is good - though maybe not as good as the 50mpg we can get out of the diesel Skoda estate. On the positive side I expect our yearly mileage to go down, as M isn't going to be working 45 miles away so much. But maybe there's another negative: town driving, which is what it'll be used for, emits more per mile than motorway driving. I think. Anyone know some real stats on all this?(Added later) I've now found What Green Car? website which rates different cars by its fuel cycle, life cycle, and impact of emissions. The Skoda estate gets 53, and the compact the rather better score of 93. The top score appears to be the Hummer which gets 91 - I'm disappointed that the Skoda is only half as bad as that monster ... Maybe I should keep track of our mileage in both, with the aim of looking to make it reduce each year. I have a very basic device on my bike that I think ought to be able to act as an odometer as well. Or do I just have an unhealthily scientific interest in measuring things? (Still the mantra of the most senior techie at work is "If I can't measure it I can't manage it." which does make a lot of sense.)