Some anti-cycling people love to accuse cyclists of not paying road tax.
Road tax doesn't exist. What they mean is Vehicle Excise Duty, which is a tax based primarily on the size and emissions of the vehicle. There is a system of emissions bands ranging from A (<100g/km CO2) to M (>255g/km CO2). An increasing number of drivers, along with cyclists, mobility scooter riders and pedestrians, pay nothing at all, if their car is in VED Band A. Cars in Band B and Band C attract a low rate (£20 or £30/year respectively), along with smaller motorcycles. HGVs on the other hand pay a higher charge.
VED does not confer a right to use the road, and is not proportional to how much the vehicle is used on the road. Which is why taxis which may cover 50,000+ miles a year pay the same as a vehicle that only covers 1000 miles.
VED (like most UK taxes) is not hypothecated. VED is simply part of the general tax take. If the tax take from VED increases, the road system does not get more investment, and similarly, if the tax take from VED decreases, the investment in roads does not go down as a result. You could however ask the question, does VED actually pay for the road system? VED revenue was £5.8bn in 2008/9 (source: IFS forecast). That's only a little bit less than the two road projects that were recently suspended: the M1 widening (£5bn) and the A14 upgrade (£1bn).So it's rubbish to say that VED comes anywhere near covering the road building and maintenance budget. Bear in mind also that the £5.8bn includes commercial vehicles. Everyone who buys goods and services in the UK contributes to the VED on commercial vehicles, because that cost is built into the price of the goods and services we consume.
So there are two main arguments here:
Accusation: Cyclists have less right to use the road than car drivers because they don't pay road tax.
Refutation: VED is not hypothecated. Band A car-owners, pedestrians and mobility scooters pay nothing, so why are cyclists specifically a special case? Because cyclists pay general taxes they contribute to the upkeep of the roads, even though they are not allowed to use motorways.
Accusation: Cyclists should pay road tax because they use the roads.
Refutation: On what basis? If it's on the basis of emissions, which is the basis of the current system, then they would pay the same as the lowest-emitting vehicle, which is nothing. If it's on the basis of mileage, then in effect you're talking about road pricing. Given the very low average mileage of a cycle, the cyclist would pay close to zero, and higher-mileage drivers would pay a lot more (and quite rightly so). If it's on the basis of impact on the road system - i.e. vehicles that damage the roads most or consume the most roadspace pay the most - then cycles would pay close to zero.