The pressure of traffic jams on the Dutch road network increased 25% this year, the biggest ever annual rise, according to traffic information service VID.

The VID calculates traffic jam pressure by multiplying the length of the jam by the time it took to disperse. There had been a steady drop since 2007.

November, in particular, was a difficult month of the roads, the VID said.

The rise is partly due to the improvements in the economy, which have led to an increase in the number of vehicles on the roads. However, the impact of road widening schemes have now run their course and new traffic bottlenecks are emerging, the VID said.

The worst stretch of road for jams this year was the A20 between Hoek van Holland and Gouda. It accounted for two of the top 10 black spots. Third was the A1 between Amsterdam and Amersfoort at Eembrugge.