A really interesting piece here that highlights the fact that despite improved miles per gallon, and a decline in emissions from individual cars, the level of road transport emissions has risen since 1990, according to the ONS.

This is because the number of cars on the road has continued to grow - something that is apparent on my drive home every day.

However, you might wonder whether the increased efficiency of cars is a double-edged sword - if cars are more efficient, they are cheaper to run and hence people will drive them more.

The only 'cost' that has significantly increased since 1990 will be the opportunity cost of being sat in traffic, and most commuters will simply have to lump that - there's not really much alternative to going to work.

Unless, of course, you could persuade people driving to work to take public transport.