Wakefield Council invested £600,000 to replace traffic lights at the Town End junction in Pontefract with two new roundabouts.
Work on the scheme started in March last year and was originally expected to be completed by the end of July.
But additional work to dig up pipes and cables caused the project to be delayed and the work was eventually completed in December.
Coun David Dagger, the council’s cabinet member for transport and highways, said traffic was now moving freely in the town during peak times.
He said: “Since the completion of work on the Town End junction, drivers have told us the traffic is flowing better and this has improved their journeys. Town End junction is one of four road schemes completed in the area.
“I believe the combination of all these changes is helping to keep the traffic moving, and is making it easier for people to get around the area. There will, though, be busy times and of course periods of congestion.”
The other schemes included the Northern Link Road project to create better access to junction 32 of the M62, new traffic lights being installed on Park Road, Pontefract, and improvements to the junction of Park Lane, Pontefract.
The council first announced plans to improve Town End in February 2011.
Transport bosses earmarked the site as a transport priority after it was found to have the worst traffic congestion levels in the district.
Work started on the scheme in March last year following the completion of the Northern Link Road.