Roadworkers will soon help Dunedin's southern gateway lose its bottleneck after officials yesterday confirmed they had the money to widen it.
The New Zealand Transport Agency (NZTA) has allocated $19.5 million for the first stage of the two-stage Caversham Highway improvements project, a decade after the rest of the valley's highway was widened to four lanes.
Stage one will double to four lanes the highway between Andersons Bay Rd and Barnes Dr, before stage two further widens and realigns the route to Lookout Point, which was widened to four lanes in 2000.
NZTA was committed to fund both stages of what will be one of the biggest road projects in Otago since the completion of the Fairfield motorway in 2003.
Confirming the details, NZTA Otago-Southland acting regional director Bruce Richards said stage one would complete the total four-laning of the southern arterial route between central Dunedin and Mosgiel.
It would be upgraded to a median-divided, four-lane route between the King Edward St overpass and Barnes Dr, with a new two-lane bridge built to the west of the bridge at the Glen.
The Goodall St overbridge would be extended and raised, while the path between Bridge St and Barnes Dr would be widened and cross the overbridge to link Barnes Dr with Kensington Hill.
Contractor Downer EDI Works expected the project to take between 20 and 24 months to complete, leaving motorists with a safer and significantly less congested route into and out of the central city, Mr Richards said.
NZTA project manager Simon Underwood said construction would start in earnest after Christmas - heavy earthmoving vehicles were expected on site in late January - but the highway would remain "live" and there should not be major, long-lasting disruption.
There would be traffic controls in place and "rare" detours when the Goodall St overbridge was lifted from above the highway. The northbound on-ramp from the Glen would also be permanently closed from early January.
Mr Underwood acknowledged neighbouring residents had been concerned about the appearance of some elements, ground stability around the Glen area and Clyde Hill, and noise coming from the new road.
Landscaping would tackle visual issues, while in the area around Clyde Hill, geotechnical testing influenced the design to see the road largely skirt around the hill, he said.
The noise issue had "still not been closed out". NZTA's preferred option was to address noise with low-noise road surfacing, but residents had a petition encouraging NZTA to build tall safety barriers, to physically block noise.
Mr Richards said the $19.5 million came from NZTA Otago-Southland's "regional dollars", a limited, $80 million fund provided from a petrol tax.
The fund might not be available after 2015, he said.