Lancashire County Council is to trial a new layout on the Penwortham flyover in an attempt to ease congestion.
The road towards Preston docks will now feature cones and signals to create a single for traffic approaching from Penwortham Hill.
Traffic from Penwortham will still have to give way to traffic from the flyover, but a longer taper on the approach means more time for drivers to merge.
The new layout will was put in place on Monday 23 February following the evening rush hour.
Phil Barrett, director for Lancashire County Council highway services, said: “The changes put in place last year have given priority to traffic on the flyover to take into account that there are now two lanes of traffic on the flyover.
“The extra lane adds capacity and helps to deal with the added weight of traffic that we have coming into Preston from South Ribble at peak times and which is set to grow as the new highway infrastructure associated with the City Deal comes forward.
“This has been successful at reducing congestion on the A582 but not all drivers have adapted well to the change of priorities at the junction with Penwortham Hill and, while the new junction is laid out according to national regulations and is safe if used as intended, we are responding to the way some drivers are actually behaving.
“The new system we’re trialling still gives priority to traffic on the flyover but is intended to make it easier for drivers to use the junction. We’ll continue to monitor the situation to see how it is working and consider what the best permanent solution may be.”