Temporary traffic lights are now in operation as part of a £400,000 Keighley scheme to reduce the risk of sewer flooding.
Yorkshire Water is installing a large underground storage tank in the council depot grounds, off Spring Gardens Lane.
The project – being carried out by engineers Mott MacDonald Bentley – involves the construction of two manhole chambers opposite Holy Family School, which has required the provision of lights for two months.
Yorkshire Water project manager Dominic Cunney said: “We recognise a scheme like this is always likely to result in some disruption.
“We want to reassure local residents, road users, schools and businesses that we’ll be doing everything we can to keep any potential disruption to an absolute minimum.”