My own personal observation I live near several families with large SUV type cars - which hardly ever move. the families walk to school and around the locality, Their cars appear to be used for the big family holiday trips a couple of times a year and the DIY type trips. Also, I personally know families who have the big car (for driving across europe) and a small electric car for everyday useage. Lucky to be able to afford I know, but again, just because there is a big fat car on the drive, it may not be adding to pollution each day.