As a result of concern from local residents and Porirua City Council, the NZ Transport Agency has been looking at options to improve the flow of Paremata Roundabout. There are significant delays and safety issues for traffic travelling south on SH1 during afternoon peak hours, as well as traffic exiting the Paremata Park and Ride during afternoon peak hours. This is due to the large number of uninterrupted right turners from the northbound approach into Paremata roundabout. The lights will stagger the entry of northbound traffic into the roundabout and create a smoother flow for other users, particularly southbound traffic and people exiting the Park & Ride.
A metered traffic light is similar to a normal traffic light, but it only has red and yellow lights. If there is no yellow or red light, northbound traffic can continue to the roundabout. When the yellow light comes on, vehicles should stop, and when the red light is on, vehicles must wait at the lights. When the red-light phase finishes, northbound traffic can continue on to the roundabout, following the normal give way rules.
Initially, the system will operate between 4pm and 6pm on weekdays, although the lights will only be triggered once the state highway southbound or Paremata Park and Ride queues reach a certain length. At that point, the lights will activate and begin to stagger the flow of northbound traffic approaching the roundabout.
This metered light and the ramp lights you see in Auckland are similar, as they both aim to control traffic flow in peak periods. The main differences are that the lights at Paremata roundabout will just be yellow and red, while the Auckland ramp lights have green as well. The Auckland ramp lights are also designed to let one car per lane to go at a time, encouraging safer merging. The Paremata lights will hold traffic for slightly longer periods, but then allow the free movement of vehicles for a set duration. The duration of the lights will be determined by queue lengths on other approaches to the roundabout.
Having a green light may give drivers the impression that they have the right of way when entering the roundabout, especially given their proximity to the roundabout. The lights are being used to stagger traffic, not to provide right of way, so road users need to be aware that give way rules still apply at the roundabout at all times.
There will be a stop line prior to the pedestrian overbridge where the lights are attached. Once you are through the lights, regular give way rules apply at the roundabout.
You can enter the roundabout at any time unless there is a yellow or red light showing. The yellow light indicates that you should stop, while the red light indicates you have to wait at the lights. If neither of those lights are showing, you can proceed to the roundabout as normal, following the give way rules.
The length of the red lights will vary depending on traffic flows. Initially, northbound vehicles will be held at the lights for between 15-30 seconds, allowing vehicles travelling in other directions to enter the roundabout safely and freely, and balancing out the queues. When the red-light phase finishes, northbound traffic will have between 45-60 seconds to enter the roundabout, before the next red-light phase. The operating hours and length of red lights may change following a period of monitoring and refinement.
We will be closely monitoring the performance of the lengths and the impact that they are having on traffic travelling in all directions. If we find that queues are becoming too long, we can change the sequencing of lights, or switch them off entirely if needed.
While there will be changes to traffic flows, it is too soon to know what they may be. We will be closely monitoring traffic flows ensure the lights are having the optimum effect. In the event of unexpected delays or congestion elsewhere, we can change the length of lights, or even switch them off if necessary.
While the opening of Transmission Gully may help alleviate congestion and improve traffic flows, there are still some current safety and operational concerns caused by traffic blocking the roundabout and vehicles attempting to squeeze into gaps in traffic. The creation of 72 more carparks at Paremata train station Park & Ride will only increase the pressure on this intersection.
Installing a metered light is intended to make the roundabout operate more efficiently and provide a better journey for road users. For southbound vehicles and vehicles exiting the train station, the light will create more gaps in traffic, allowing easier and safer access into the roundabout.