The overnight closure of the A61 at Wakefield is expected to cause delays this weekend - and a further two months of work are planned at the site.
A lane of the A61 will be closed on Kirkgate, under the railway bridge at the junction with Doncaster Road, while work is carried out to improve the bridge.
The lane will be closed overnight between Saturday, August 24 and Sunday, August 25, and again between Saturday, August 31 and Sunday, September 1.
In each case, it is understood that the lane closure will be in place between 7.30pm and 6.30am the following morning.
A long-term lane closure will also be in place between Monday, September 2 and Friday, November 1, while more work is carried out.
According to roadworks.org, "major bridge repairs" will be carried out between 9.30am and 3.30pm during this time.
A spokesperson for Network Rail said: "Network Rail is doing a lot of work to improve railway bridges in Wakefield over the coming months.
"There are four bridges being upgraded; these are Ings Beck, A638 Ings Road, Sunderland Yard and A61 Marsh Lane. Work on the upgrades began in July and Network Rail will be on site until late March 2020.
"Network Rail is carrying out repairs and maintenance work to the bridges. This includes work to strengthen the bridges, make them more weatherproof, work to the drainage and to replace the bridge decks.
"After this, the bridges will be cleaned through grit-blasting and will then be repainted.
"Whilst this work takes place, there will be temporary traffic management in place, including road lane and footpath closures. There will be clearly signposted diversionary routes whilst this is in place.
"We would like to thank all those who are impacted by this for their patience and apologise for any disruption caused."