Using a radar system, the electronic signs are activated when traffic on Kennington Rd or Kennington-Roslyn Bush Rd is detected approaching the intersection with State Highway 1, about 12km from Invercargill.
If there is traffic on the side roads, all four signs illuminate, telling motorists to reduce their speed to 70kmh. If there is no traffic on the side roads, the highway speed limit remains 100kmh.
Motorists on the side roads were supposed to stop at the intersection, but mistakes happened, NZ Transport Agency senior network manager Peter Robinson said, activating the signs yesterday. About 5400 vehicles used the highway daily, with about 900 using Kennington Rd and 870 using Kennington-Roslyn Bush Rd, Mr Robinson said. There had been 20 crashes at the intersection in the past 10 years, four involving serious injury.
The Kennington signs, which cost $250,000 to install, are part of a six-location trial. Four locations are in the North Island and the other is at Yaldhurst, near Christchurch.