Road tax is a way of ensuring vehicles are insured and MOT'd, which is one of the reasons I believe for the recent change where tax cannot be transferred with the vehicle. For this reason I am happy to keep road tax, although given the tax breaks for low emission cars, I think it is too high on bikes. The vehicle has to be insured and MOT'd to be taxed, and Road Tax is very easy to monitor, if a vehicle is not SORN'd or taxed, they can automatically issue a fine and ANPR will pick up vehicles that are not taxed. It would not be so easy to monitor insurance and MOT's. If it helps to keep the number of uninsured vehicles on the road down than I am in favour of it.