Sir, – Brian Manley (Letters, February 20th) raises an excellent point on motor taxation — that annual motor tax bands incentivise the purchase of new cars which require enormous amounts of energy to manufacture.
Indeed, the current tax regime appears to have been designed by someone unfamiliar with the fundamentals of chemistry: a kilogram of fuel mixed with oxygen produces the same amount of total emissions no matter how advanced the engine involved.
While some cars cover a greater distance on this kilogram and others use sophisticated techniques to reduce consumption while idling, the simple fact is that CO2 emissions cannot be “magiced away”. Therefore the fairest emissions regime should be based on carbon inputs rather than imputed outputs.
These theoretical outputs bear little relation to real-world driving conditions.
Additionally, across the EU diesel is favoured over petrol to the extent that European refineries now export gasoline to the US while shipping diesel in the opposite direction.
As refinery output is relatively fixed this perverse arrangement will last as long as officialdom favours diesel cars whose supposed environmental benefits never accrue during the short journeys typical of city dwellers. – Yours, etc, MATTHEW GLOVER Lucan, Dublin