Motorists heading into North Wales any time in the next couple of months can expect to face delays.
Work to improve safety in the Conwy tunnels got under way last night (January 22) and is scheduled to last for nine weeks.
The work between J17 for Conwy and J19 at Glan Conwy is being undertaken as part of a £42m scheme to upgrade A55 road tunnels.
On Monday morning, there were some delays westbound in the Penmaenbach tunnel area as two lanes converged into one.
Improvements in the Conwy tunnels include upgrading and replacing signs on the approach that are used to close the road and tunnels in emergencies.
Temporary crossovers in the central reserve will also be relocated and a gated vehicle restraint system installed.
Resurfacing will also be carried out and new lighting installed as part of the major project.
According to the Welsh Government the work will 'improve the overall level of safety and resilience of the Conwy Tunnel'.
During the roadworks there will be lane closures and contraflow traffic management in both directions between J17-19.
Traffic bosses say that there will also be 'occasional' closures of the westbound carriageway to allow for a crane to remove and install signs – however these shut-downs will only take place between 2am and 5am.
Wide and abnormal loads will also have to be escorted through the Conwy Tunnel when width restrictions are in place during 'pre-advised' time slots to limit disruption.
The speed limit on the stretch of road will also be reduced to 40mph with average speed cameras in force.
A Welsh Government spokesman said: “The works have been planned during the winter months when traffic flows are lowest.
"During the closure, contractors will be working whenever and wherever practically possible 24 hours per day, seven days per week throughout the construction phase period to ensure overall disruption to the travelling public is kept to a minimum.
“Options for minimising disruption during the day have been fully explored. The safety of the travelling public and site workforce was the primary consideration when determining the safest implementation method for the Conwy Tunnel Improvement Works
"It was concluded that the risks to traffic management operatives and members of the public from closing and re-opening the tunnel each night was not feasibly practical.”
The work is scheduled to finish by Friday, March 31.