A leading business group in the West Country says productivity is being damaged by the amount of road congestion.
The Somerset Chamber of Commerce has called for councils, utility companies and developers to ensure fewer sets of works over-run.
Last year more than 150 extra days of roadworks took place in Somerset because of project delays.
An ITV freedom of information request shows that of nearly 1500 sets of maintenance roadworks commissioned by Somerset County Council over the past year, there were 158 days of them over-running.
The man in charge of Somerset's roads says those numbers don't tell the full story.
The man in charge of the Somerset Chamber of Commerce wants to see more of the M5 in Somerset as a 'smart motorway' which varies the speed limit and opens the hard shoulder to ease congestion.