The changes follow an Australian system that uses amber and red traffic light signals only, with no green.
"The changes include two-aspect traffic lights, amber and red with no green, widening the existing median island on SH29A west-bound approach, installing a median island on Pyes Pa Rd, moving the traffic lights 30m from the roundabout approach, and improving kerbing," Campbell said.
This will be trialled for 12 to 18 months.
When traffic queues on one leg activate the metering, the traffic lights will turn amber then red to stop the vehicles, allowing traffic from the busiest road to enter the roundabout.
Give way rules still apply when entering the roundabout.
The traffic lights on SH29A will be phased to ease queues on Pyes Pa Rd when it is busy, which is predominantly during the weekday morning peak.
The traffic lights on Pyes Pa Rd will be phased to improve traffic flow on SH29A from Tauriko during the weekday evening peak.
Campbell said the Pyes Pa Rd approach to the roundabout was busier than the other roads in the morning peak so the traffic lights on the SH29A westbound approach would hold back traffic to allow Pyes Pa Rd traffic through.
"Similarly, the traffic lights on Pyes Pa Rd will be phased to improve the flow for eastbound traffic on SH29A from Tauriko during the weekday evening peak.
"Most of the time the traffic lights won't be activated, except when high traffic queues on one leg activate them, then the traffic lights will turn red to stop the vehicles, allowing traffic from the busiest road to enter the roundabout. The red phase is short and will turn off before another large queue is created."
Roundabout metering will also be installed on SH2 Takitimu Drive and Elizabeth St roundabout with traffic lights on the SH2 northbound approach to the roundabout.
These will be operational in early 2019.
The work is part of a wider programme being implemented across the region to improve safety and journey times.
For more information: https://www.nzta.govt.nz/projects/tauriko-network-plan/publications