RAA expert reveals how to make Adelaide red lights go green

There really is something you can do to make the red light turn green. But rumours of pressure plates under the road are urban myths, this expert says.

It’s every motorist’s annoyance — the traffic light that just won’t turn from red to green.

You’ve been waiting for what seems like ages but the light stubbornly stays on red.

So should you creep forward? Reverse a little?

Is it because that lone cyclist at the head of the queue is too light to trigger the change?

Turns out there is a way to encourage traffic lights to change but first you’ll need to put aside all the urban myths about how they work.

RAA senior manager of safety and infrastructure Charles Mountain only had to stroll out the front of the RAA headquarters at Mile End to find the perfect example of how to deal with the system.

It turns out inductive loops under the road surface detect metal, not weight, so a motorbike, pushbike or even a scooter can trigger an alert.

However, you have to be in the right position. Which turns out is not difficult if you stick to the road rules and pull up at the unbroken stop line.

If you go too far, the loops won’t register you as stopping and will not start a lights sequence change.

The ute is too far over the white line to trigger the loop.

And if the car behind does not move up enough in such a situation, it won’t trigger the loops to act either.

Mr Mountain found the precise situation where a grey ute had gone too far over the loops to activate a change, while the red Mazda behind had not gone far enough.

The vehicles waited at the unresponsive red light for around seven minutes before the ute finally took a chance and drove through the red light.

The Mazda then moved up, triggered the loop and the light changed to green almost immediately.

“The moral is to pull up just before the stop bar, so that all or a good portion of your vehicle is over the loop,” Mr Mountain said.

“These loops are at pretty much all traffic lights and in all lanes, they detect the presence of a vehicle to active the change of lights and also measure the number of vehicles going past and the gaps in traffic.

“This helps to manage traffic flow very efficiently.”

The loops are laid into gaps cut into the asphalt road surface which are then sealed.

Mr Mountain noted some motorists may feel like they wait ages on side streets for a light change allowing them to enter a busy street but the loops are working to maximise efficient traffic flow.

The same lights may change much faster late at night when the loops on the busy road monitoring vehicles and gaps detect less traffic.

Motorists who think a loop is not working properly can contact the Traffic Management Centre at Norwood, ph 1800 018 313.