Motorists are being warned to expect significant delays when major roadworks begin on State Highway 3 in Taranaki tomorrow.
Waka Kotahi is rebuilding several sections of road between Inglewood and Midhirst, through to early December.
Light vehicles travelling south will be required to take a 40km detour adding about 25 minutes to journeys between Hāwera and Midhirst.
Southbound trucks will be convoyed through State Highway 3 every two hours.
Northbound traffic will continue to use the highway, but will be held at Tariki to let trucks through.
All traffic, especially heavy vehicles, travelling between Hāwera and New Plymouth is encouraged to take State Highway 45 (Surf Highway).
Regional manager maintenance and operations for the Central North Island Jaclyn Hankin said the detour route would save considerable time compared to the cumulative delay if a Stop/Go system was used at each of the sites.
"We understand this detour is inconvenient but after investigating several options for managing traffic during these large-scale works, we've concluded the detour has the least impact on all road users and is the safest, most efficient way to complete the work.
"This is a large amount of work to do on this road and having a detour in place will enable crews to safely work on several sections of the road at once, reducing the overall construction time significantly."
Light southbound traffic will be detoured from the intersection of SH3 and State Highway 3A in Inglewood, re-joining SH3 at Beaconsfield Road in Midhirst via Tarata, Kaimata and Salisbury roads. Salisbury Road between Croydon and Tariki Rd South will be one lane, open to southbound traffic only.
Southbound freight and haulage will use State Highway 3 via convoy from Durham Road every two hours or State Highway 45.
Additional safety measures including new line markings, signs and temporary speed limits will be implemented on the local road detour route.
Hankin said the work would significantly improve the condition of the highway.
"This highway is a vital link for the region, and we know that the community and freight industry have raised concerns about the condition of the road."
The highway would be reopened to two lanes for Labour Weekend and again from Friday 29 October to Sunday 7 November to ensure the successful running of the Taranaki Garden Festival and Taranaki Arts Trail events.