MOTORISTS were being braced for three months of travel disruption in Glasgow while major repairs are carried out on one of the busiest road bridges in Europe.

From today, lanes on the M8 Kingston Bridge ‘south approaches’ will be narrowed with a reduced speed limit of 40mph as the second phase of upgrading works gets underway on the eastbound carriageway.

Drivers were warned to expect delays of, “up to 20 minutes” during peak period, by TranServ, which maintains the trunk road network across south-west Scotland.

However, motoring groups said this was likely to be a "conservative estimate" and was advising motorists to allow more time for journeys and consider park and ride, public transport or flexible working options.

The eastbound carriageway will be closed overnight from Sunday until Wednesday, January 10 to implement the narrow lanes and erect a temporary vehicle barrier.

Traffic will be diverted onto local roads before joining the M8 eastbound carriageway beyond the works area.

Carrying the M8 motorway through the city centre, the Kingston Bridge is one of the busiest road bridges in Europe, with around 150,000 vehicles crossing every day.

Rodney Kumar, of IAM Roadsmart said: “The work hits the time when all the schools are back, office workers are back.

“You have to be forward thinking, don’t bury your head in the sand.

“I’m sure they have come to up with the 20-minute estimate using data and knowledge but there is always the potential for longer delays on heavier load days such as Mondays.

“It could be more, it could be less. Fridays might be easier, when more people work from home.

“You have to take any delay estimate conservatively and allow extra time for travel.

“The work does have to happen and people need to ride it out. It’s about how we go about our day.

“In a situation where there are delays, allowing more time is the best thing we can do.

“Park and ride and public transport is another option which makes sense.

“It’s also about asking yourself, are there any other alternatives?

“Is there is any flexibility in working hours that will allow the shifting of that work outside the normal 8-9am?

“People just need to see how much leeway there is.”

Work is being carried out to replace the edge coping, vehicle barriers and expansion joints on the east bound carriageway.

An upgrade of the west-bound carriageway got underway in October and the overall project was originally scheduled for completion in February but TranServ said the recent bad weather had delayed progression.

Peter McCann, Scotland TranServ’s Major Bridges Manager said: “The Kingston Bridge and its approaches are now 50 years old and require regular routine maintenance. The crossing is the busiest in Scotland and is an integral part of life and business in the West of Scotland.

“The westbound phase of works has been delivered with everything possible done to minimise disruption for road users. We’ve been working in liaison with Police Scotland, Local Authorities and key stakeholders to ensure that this next phase of essential improvement work is delivered in a similar manner. Narrowing the lanes will allow our contractors to work as quickly and safely as possible, while maximising the traffic flow.”

“Whilst the westbound phase of works was delivered with minimal delay, potential delays of up to 20 minutes have been forecasted by our specialist traffic flow modeller and we would ask drivers to either allow additional time for their journeys, seek alternative routes or travel times.

“They could also consider park and ride or switch to public transport. We would advise motorists to always check latest roads information on trafficscotland.org or by following @trafficscotland on Twitter.”

When opened by Queen Elizabeth the Queen Mother in 1970, the bridge was designed to handle 120,000 vehicles a day.

By 1990, the sheer excess volume and weight of traffic, combined with poor design and flaws in construction, resulted in serious structural deterioration.

A decade-long repair and renovation programme was initiated to repair and strengthen the bridge.