Environment saved

I was keeping this for Radio 4's Genius program, but the need is too urgent to wait for a new series.

I think that most of the drivers I know don't care about the damage they're doing to the environment and to the lungs of pedestrians because they're insulated from the immediate effects. Likewise, the exhaust fumes disperse and we don't really notice it any more.

So the way to shame people into driving less or driving cleaner cars is to increase the immediate effect of the pollution. I have the answer. Add harmless black dye to the exhaust so that each vehicle pumps out a foul black cloud proportionate to the pollution produced, so that everybody can see whose cars are poisoning them, and gains a visual index of the degree to which our air is polluted. Link it to another pump which exudes a revolting but harmless gas into the vehicle's cabin - I suggest the eggy deliciousness of human flatulence - in proportion to the engine output (for SUVs, I'd prefer to link the exhaust pipe to the air conditioning, but apparently that counts as murder).

Before long, the selfish bastards in urban SUVs will be rushing to buy Prius's as their clothes stink of bottom and passing pedestrians lob bricks at the filth factory speeding past. It won't cost drivers any more, it doesn't penalise people who have to drive for work, it simply emphasises the costs of how we run our society.