It appears that steep rises on the M6 toll road mean motorists are going back to the traffic jams on the old M6 route.

The M6 toll was designed to handle 100,000 cars a day – the normal figure for a three-lane motorway. However, last year it was handling just 34,000, down from 55,000 in 2006, and the lowest figure since it opened in 2004. Since 2004, tolls have gone up from £2 to £5.50. Most of those displaced cars appear to have gone back to the old route, which is now gridlocked again.

The root of the problem seems to be another government miscalculation (see rail privatisation, Private Finance Initiative etc.). Their logic was that they did not need to regulate tolls - the owners, Macquarie Infrastructure Group, once pointed out to its shareholders that the M6 was the largest toll route in the world that had no regulation. This was because competition from free roads would keep the price down, as the owners would want to maximise traffic.

Basic economics says that the owners will want to maximise revenue and minimise maintenance costs for renewing the road surface. It is more profitable to have half the number of cars paying twice the price, as any A-Level Economics student could calculate.

In the meantime, we have a huge motorway that has carved through the West Midlands countryside, as it was largely built on green belt land, and only a small impact on congestion. Another triumph for Whitehall.