North Canterbury drivers can expect significant delays during their morning commute to Christchurch over the next month for road resurfacing.
It is part of the final stages of the Christchurch Northern Corridor motorway project.
Work on the southbound lanes of the Waimakariri Bridge will start on Saturday afternoon, continuing into late September.
As a result, the Tram Road on-ramp will be closed between 5.30am and 9.30am on weekdays.
NZ Transport Agency Waka Kotahi portfolio delivery manager Colin MacKay said road users should prepare for significant delays during morning peak from Monday into late September.
Traffic would move over to the middle lanes during resurfacing of the southbound lanes before work begins on the northbound lanes, he said.
"Resurfacing work will start on the existing southbound lanes, affecting the morning flows, followed by the northbound lanes. Depending on the amount of preparation work on the old deck and favourable weather conditions, we expect each side to take around four weeks to complete," he said.
"Once the bridge lanes are complete, the surfacing crews will move to the SH1 lanes north and south of the Waimakariri Bridge. The resurfacing work will be complete before opening of the new Christchurch Northern Corridor motorway including the new carpool lane from Tram Road in December."
MacKay recommended people should travel outside of peak hours in September if they could or leave earlier than usual.
"With traffic moving over to the middle of the bridge and merging back, movements will be much slower than usual. Especially during the morning peak, Tram Road users should also expect delays at the Tram Road and Main North Road intersection as we will be using Stop/Go controls," he said.
"Within the four weeks of working on the southbound bridge lanes we will need to do quite a lot of work to first inspect the bridge decks, to repair and strengthen several bridge joints and structural work to the abutment before we can apply a good new surface."
The heavy haulage industry has been informed that the inner bridge lanes used by traffic during resurfacing won't allow for some over-dimension vehicles and loads, he said.