The new structure was to be constructed in a way to minimally affect the traffic flow on this crucial motorway link, by first constructing a new viaduct of four southbound lanes to the north-east of the existing structure, then demolishing the existing three southbound lanes, before constructing the three new northbound lanes in the gap and finally demolishing the three old northbound lanes. It was originally considered whether to build a 'steel box' or a 'concrete box' structure, though both would look similar to the existing viaduct structure. It was eventually decided to construct a segmented structure built from 468 pre-cast concrete sections constructed off-site in East Tamaki, and moved into place with a lifting gantry truss.