The price of fuel and the credit crunch have had an pleasant unexpected effect - cutting traffic jams on motorways and trunk roads by 12% over the last year.

Statistics from the RAC Foundation and Trafficmaster show evidence that congestion is reducing and journey times are getting quicker.

The northern section of the M25 saw the most dramatic fall in congestion, with a 26% reduction in traffic jams in the first six months of 2008, compared with the previous year.

The motorways around Greater Manchester show some of the steepest cuts in journey times. The M6, M62, and M56 have seen a consistent decrease in both north and south-bound journey times over the past year.

Even the notorious M6 between Manchester and the Midlands experienced a dramatic speeding-up between last year and this. The current 1hr 6 minutes from Staffordshire to Warrington is more than 5% quicker than last year. That improvement is beaten only by the M6 toll road south of Birmingham and the A14 Ipswich to Cambridge road.

Although journey times across the whole network were cut by an average of 12%, drivers actually slowed down from 63.3 mph to 62.2 mph over the last year as they tried to save fuel.

Sheila Rainger, head of campaigns at the RAC Foundation, added: ‘The fall in congestion is good news in an otherwise-bleak picture for UK drivers, and shows that motorists are moving journeys out of peak hours, where possible.

‘However, this altered pattern of demand can only be a breathing space for policy-makers, and does not remove the case for investment in a package of congestion-busting measures.’