Another London transport topic that has made its way across the Atlantic, The Canadian Press (via Breitbart) reports: London suburb to charge drivers parking fees based on emissions. Richmond upon Thames, a Borough of London, wants to charge £300 for cars to park in front of their houses if the cars are of models that are classified as big polluters (the local term: Chelsea Tractors).
The irony is that they are charging the cars when they are not polluting (i.e. when they are parked) rather than when they are.
Again, the technology could relatively easily be assembled to charge cars based on how much they pollute, that would be in the long run both more fair and more efficient. Robert Harley was doing tests on the measurements of this more than 10 years ago at Berkeley, see this paper for an example. That would just need to be tied to transponders or license plate matches (a la electronic toll collection or the London Congestion Charging scheme) and a price developed.
The continued use of second (or third) best solutions when much better ones are available is unnecessary.