Simon Heffer made an interesting point in Saturday’s Telegraph about Dartford Tunnel tolls. He suggested that the main cause of congestion on the M25 near the tunnel and bridge was the existence of the toll booths. My experience suggests that he is almost certainly correct.
There are several economic justifications for road pricing, of which three are:
1. To ration scarce road space when it is highly congested and volumes have to be reduced.
2. To produce a level playing field with competing modes of transport that might be charged at the margin.
3. To make traffic pay the externality cost of congestion.
I shall ignore pollution/global warming arguments as, even under Stern’s projections, current petrol tax more than pays the externalities caused as a result of these effects.
If the toll booths are the main cause of congestion then clearly arguments 1 and 3 do not apply to the Dartford Tunnel. 2 also does not really apply because there is no meaningful competing alternative to driving round the M25 in your car (at least at this point). The further nail in the coffin for the tolls should be the realisation that the tunnel and bridge are connected to a network (inner London and the rest of the M25) which is more congested than the bridge and tunnel themselves and for which there is no charge. Thus the relatively uncongested bit of the network is the bit that bears the charge!
Quite clearly this charge is on the wrong bit of the network. I have a proposal that would involve no great change to the way in which road pricing was currently undertaken (though long-term change is necessary) and would involve a simple Bill.
We could take a bit (or bits) of the road network that are congested and the use of which leads to greater congestion elsewhere on the network. If these bits had few or no viable competing uncharged roads but did have competing public transport this piece of the network could be charged for on a congestion charge basis (free at night or when uncongested) without any knock-on effects on other bits of the network. It would be a simple “win-win” Act of Parliament that would impose a charge on this piece of road that would benefit from a charge and eliminate all bridge tolls where the charge is destructive. The Act could be designed to be revenue neutral requiring that any excess revenue was used to reduce Vehicle Excise Duty (road tax). Revenue neutrality would also enable any outstanding PFI deals to be sorted out. The piece of road I suggest is the M4 Heathrow spur. A congestion charge on this would be highly efficient.
The cause of congestion on the Darftord stretch of the M25 would be eliminated; bridge tolls with no economic rationale would disappear; and a stretch of road which is highly congested would have a charge imposed. This charge would be easy to collect too. Cars that use the Heathrow spur can only end up in one place and there is bound to be somewhere where it is easy to collect the charge.