The NZ Transport Agency (NZTA) will test the operation of the warning signals and traffic barriers located at each end of the Johnstone's Hill Tunnels on the Northern Gateway Toll Road later this month.
The first tests will be held later this week before Easter, and the second next week after the long weekend.
"We can't give the precise time because the reaction of drivers is an important part of the tests," says the NZTA's Principal Project Manager for the Northern Corridor, Brett Gliddon.
Mr Gliddon says the tests will cause only minimum delay to drivers, and they will be held at times of the day when traffic volumes are low. There will be no tests during the Easter weekend.
The warning lights and barriers are part of the toll road's safety measures and are used to prevent traffic driving into the tunnels if there is an emergency. The tests will be conducted by the Auckland Motorway Alliance, which is responsible for the operation of the 220 kilometre Auckland motorway network.