DRIVERS have been warned to expect severe delays in the centre of Brighouse from Monday.
Gas pipeline company Transco is renewing pipes in Huddersfield Road and Bradford Road in a 12-week scheme.
Work will start at the junction of Huddersfield Road and Birds Royd Lane, where the four-way traffic lights will be replaced by temporary lights.
Engineers will then move gradually down Huddersfield Road towards Bethel Street.
Advance warning signs advising lorry drivers of diversions via Wakefield Road are already in place.
A free telephone hotline giving an update on progress will be available on 0800 328 4568.
Transco networks operations manager Dean Shepherdson said: "This is essential work to guarantee the safety and reliability of gas supplies in Brighouse but we realise that it will cause disruption to local people.
"We have been working closely with Calderdale's highways department to make sure we keep disruption to an absolute minimum by using trenchless main-laying techniques as much as possible and carrying out some working at weekends."