Skipper's mood has not been improved in recent months by the length of time spent sitting in his car, waiting for access on to the new Trafalgar roundabout on the main A39 in Truro. Some evenings, during rush-hour, the traffic is now backed up all the way up the hill to the junction with the Falmouth Road.

The additional travel-home-from-work time has however enabled me to reflect on a piece of 20-year-old research, commissioned by the government, which proved beyond any doubt that “roads cause cars” - in other words, the volume of traffic on any given piece of tarmac will increase to fill the tarmac available.

The 1994 Standing Advisory Committee on Trunk Road Assessment highlighted the effect of “induced traffic.” It concluded with these words: "An average road improvement, for which traffic growth due to all other factors is forecast correctly, will see an additional 10% of base traffic in the short term and 20% in the long term."

I know that news sometimes travels slowly in Cornwall, but I do wonder if anyone at Cornwall Council was aware of this research before reaching for their pencils and designing the new road scheme.

The Trafalgar roundabout is now much bigger than it was before - but the roads leading to and from it are not. And so, perhaps not surprisingly, there is now much more traffic effectively parked on the roundabout - with long queues waiting to join it.

A similar effect is evident at the A30 Chiverton Cross, on the other side of Truro, as traffic trying to exit the roundabout sometimes has to wait to join the original single-lane carriageway. If we're seeing rush-hour traffic jams like this in winter, I hate to think what's going to happen in August.

The Trafalgar roundabout cost at least £2.25 million and the Chiverton Cross scheme, completed a few years ago, nearly £4 million. It's a lot of money, but probably less than Vladimir Putin is currently spending in order to keep 30,000 troops in the Crimea.

If Putin wants a long-term way of keeping the Ukrainians out, all he has to do is ask Cornwall Council for a new roundabout.