Hutt City Council and the New Zealand Transport Agency are testing new signal phasing at the intersection to establish whether this will improve overall traffic flows.
The trial will run till at least August 10 between 6.45am and 8.30am and between 4.30pm and 5.50pm.
The main differences motorists will notice are:
Drivers leaving Harbour View and Tirohanga roads will have to wait slightly longer for a green light.
Drivers turning right from the state highway into Harbour View Road will also have to wait slightly longer for a green light.
Drivers travelling from Harbour View Road to Melling Station will have a new left-hand-turn arrow at the intersection with the state highway.