Drivers are being warned that tailbacks of several miles and delays of up to an hour are likely from the next set of Upton bypass roadworks, if drivers do not change their route.

This is the stark reality of a lane closure on the A35 north of Poole, when five weeks of work gets underway on Monday, January 14.

The need to strengthen Policemans Lane Bridge will mean the closure of the inside lane of the westbound carriageway and Dorset County Council is urging drivers to use other roads.

Modelling by engineers on the impact of the lane closure shows that the morning peak traffic flow will be around 200 vehicles over capacity and the evening around 800 vehicles over capacity.

“Many drivers tend to commute on auto-pilot, so we’re giving plenty of advance warning of this work to ensure that drivers can take action to avoid these delays from day one,” said Cllr Peter Finney, county council cabinet member for highways and transportation.

“We are carrying out this work at a time of year when the daily average number of cars using the road is at its lowest, but we know it will still have a large impact on people’s daily journeys.

“Drivers should try to understand that this work is for their benefit – the road needs to be maintained so that it can continue to be used by the thousands of vehicles that use it every day,” he said.

Gridlock was caused in early November on the Upton bypass when two sets of roadworks coincided with the refit of the Sandbanks ferry. This marked the start of 15 weeks of engineering work by the county council.

The latest lane closure will allow work to strengthen bridge support columns and carry out surfacing work, barrier repairs, drain cleaning and verge clearance.

The closeness of the bridge support columns to the edge of the road means the only way to carry out the work safely is to close a lane, says the council.

Their suggested diversion for drivers wishing to avoid the congestion is the A349 Gravel Hill up to the Merley roundabout and onto the A31.

From Monday February 18 work will move to the central support columns of the bridge and the central reservation. The eastbound and westbound outside lanes will be closed for five weeks.

During the morning peak the westbound carriageway carries around 1,600 vehicles between 8am and 9am and 2,200 between 5pm and 6pm.

What to expect:

Phase 2a – westbound works (towards Dorchester)
Jan 14: Five weeks of work to strengthen Policeman’s Lane Bridge westbound support columns and replace the safety barrier in front of the columns.
Jan 14-Feb 15: Nearside lane closed, with all traffic in the outside lane at 40mph, for tree maintenance, drainage work and barrier repairs.

Phase 2b – central works
Feb 18-Mar 22: Five weeks of work to strengthen Policeman’s Lane Bridge central support columns.
Feb 18-Mar 15: Eastbound and westbound fast lanes closed for repairs to central reservation and some drainage works.
Mar 11-22: Westbound night-time closure for surfacing works.