Who and how is the co2 emmissions decided on vehicles.?

Question

I thought buying a 1.3 cc would be less on road tax but I was wrong, it doesn't make sense.

Answer 1

I don't think the tax people have understood yet ,but it will produce CO2 exactly depending on the hp. that it produces. If U have a large motor say 100 hp doesn't mean it produces that all the time. It depends on how fast U accelerate as to the hp. used. They can measure the car exhaust but truly has no value unless it is on a Dino-meter to give the motor a load.