Highways teams will begin testing the new traffic lights by the Medway Tunnel next week - seven months after they were installed.
People working on Medway City Estate, who have been plagued by daily delays for years, have been calling for controls to ease congestion and help people get off the estate more easily at peak times.
In 2014, it seemed like their pleas had finally been answered when Medway Council agreed to put traffic lights on the Gillingham side of the tunnel.
The lights were initially promised by the end of 2015 and were eventually installed in March this year. But since then they have remained permanently on green.
The council initially said the lights would be tested in June, but this is now due to start on Monday. It will then be decided at what times they will operate.
A council spokesman said the testing will be completed manually via the traffic operations room, with the senior traffic signals engineer monitoring and releasing traffic.
They are designed to briefly hold back traffic, creating a gap on the Strood side so motorists can leave the estate more easily.
The idea followed a scheme introduced by Medway Council when traffic was made worse because of roadworks in Strood. Slow moving Highways lorries were sent through the tunnel on a loop to slow the traffic down behind it.
The delay in having the lights go live has been put down to the need for speed cameras in the tunnel.
A safety assessment after the lights were announced flagged up the need for these, to make sure motorists do not speed through the empty tunnel when the lights turn green.
The 50mph average speed check cameras were installed in June and are now live.
In 2014, more than 1,000 people signed a petition calling on the council to bring in measures to ease congestion on the Medway City Estate, which employs 6,000 people.
At the same time, highways bosses pledged to spend £2 million on improvements on the estate, including the traffic lights.
Roadworks to improve the A289 and the Anthony’s Way, Sans Pareil and Four Elms roundabouts will start in autumn next year.