alls i know for sure is using a car for a 1 mile journey is bone idol.i aint a scientist just someone who doesnt use the car for small journeys the 4x4 users seem really touchy and try defending the size of their carbon footprints.i find it all quite ammusing the [people who drop the kids off in 4x4s complain when thier little lambs have asmah get the lazy sods to walk or bike it theyll not be quite so plump either.as for my carbon footprint if the government decides to make petrol really expensive ill just jack my job and go on the dole thatd cost em if every1 did that so its better for them to attack 4x4 drivers who usually have jobs paying good money or they couldnt afford to buy or run the said deisal guzzlers