Motorists could face weeks of delays as repairs are carried out on a main road leading in and out of Wakefield.
Signs have been installed on Barnsley Road, close to the junction with Chevet Lane, to alert drivers to the road works, which will be carried out by Northern Gas Networks.
Work will get underway on Wednesday and is expected to last more than five weeks until September 3.
One lane will be closed and delays are likely.
The company said: "We are carrying out essential work to replace ageing metal gas mains in the road with more durable plastic pipes.
"This is to ensure that we continue to provide safe and reliable gas supplies to local residents and businesses for years to come."