FZP said:Ridiculous.
Porsche passes ULEZ, Road tax at the highest band
AUDI A6 fails but road tax is 1/3 of the 911.
Something isn't right
Make up your minds you (insert profanity here)
Simple, they are penalising two different emissions.
Road tax rate is based on co2 emissions. Co2 is greenhouse gas and is causing climate change. Its just as bad emitting this in town or country hence the flat rate.
ULEZ is based on NOx emissions. This is bad for human health when you breathe it in, hence why the penalty applies only in the city where its effect is much worse.
The two are not necessarily linked. A car that emits little of one might emits loads of the other.
There's no conspiracy, just poor understanding.