It isn't just the pollution. It's the increased risk at which they put pedestrians and cyclists. A sensible upper limit on car size and bonnet height would do a lot to make roads more usable by sustainable forms of transport.
Frankly, I think there's room for another zero on the end of that 100%.
While cycle commuting in Newcastle (AU), I noted that at least 4/5 of cars parked reasonably close to the curb, while on the other hand at times 4/5 of 4x4's were as close or closer to the lane of traffic than to the curb.
And here in Ohio, while walking around town I find that they are the drivers most likely to turn at a traffic light without looking to see whether there is a pedestrian crossing (in Ohio, unless posted, pedestrians have priority crossing with the red light). Utsukushikereba sore de ii
