When stopped for a red signal at an intersection you should

Is it true that you must give way to the right in all situations?

That's not always the rule.

At an unsigned crossroad, you must give way to all vehicles approaching from your right. But if you want to turn right, you must give way to all oncoming vehicles too.

If you're driving on a road that ends in a T-intersection, you must give way to all vehicles on the continuing road.

And naturally, if you come to a stop sign or a give way sign, you must give way to all other vehicles as well.

So what happens at an intersection with both a stop and a give way sign? Contrary to popular belief, a stop sign is not more powerful than a give way sign. The signs effectively cancel each other out and normal give way rules still apply. Both must give way to all vehicles, then because car A is turning right, it must give way to car B.

Finally, if you're planning to do a U-turn, you must give way to all other vehicles before turning.

Knowing the give way rules helps you drive safely and avoid crashes.

Australia’s traffic lights conform to international standards, however if you are coming to Australia from another country there may be differences in the phasing to what you are used to.

Traffic light colours and phasing

Traffic lights have the phasing red, green, yellow, red, and this applies whether they are at an intersection or a pedestrian crossing. There is no red plus yellow, and red always means stop (there’s no automatic free turn like there is in America). You must stop at a red light and wait behind the line until it turns green. Even if there is no traffic or the lights haven’t changed because the traffic light induction loop has failed, you must not go through a red light.

At some intersections, you will see a red light with a green turning arrow which permits you to turn in the direction it is pointing. If the turning arrow is red, or there is no arrow at all (but the main light is still red), you are not allowed to turn, unless there’s a filter lane to the left.

For example, the traffic light below shows that traffic going straight ahead or turning right must stop. The green filter light to the left means that traffic can turn left, but must give way to any pedestrians that are still crossing, as per the road rules.

The only time you get a free turn left on a red light is if you see the following sign. You must stop at the line first, though. The image below also shows that the light has turned yellow. A yellow light means you must stop if it is possible to do so.

A green light means you can go straight ahead, turn left (if there are no crossing pedestrians), and turn right (if you give way to traffic coming towards you).

Before you drive through a green light you must make sure there is room for you on the other side of the intersection so that you don’t block traffic. If there is, wait behind the line until it’s clear to go.

A flashing amber arrow means the lights are faulty and the give way rules apply. You can proceed if you give way to other vehicles, but only if the road you are turning into is clear of pedestrians.

Traffic light timing – phases and cycles

When the light turns yellow you must stop if it’s possible to do so. Therefore the amount of time that a yellow light is displayed is carefully timed depending on the road’s gradient and speed limit in order to give traffic enough time to stop. Too short and some traffic will not be able to stop before the line and will end up driving through a red light; too long and people learn that they can rush through the light, creating a danger then for other shorter-phased yellow lights. The phasing is roughly 1 second per 13kph with most urban intersection yellow phases between four and six seconds.

An entire cycle from red to green to yellow to red is usually between 50 and 150 seconds, although specific cases might fall outside this window.

All-red phase

The all-red phase is when every traffic light at an intersection is red at the same time. This happens for two reasons:

1. Pedestrians are crossing in all directions and have a dedicated phase
2. In every phase, there’s a time when all lights are red to give traffic from the previous phase enough time to clear the intersection (i.e. a light doesn’t turn green just because one of the other lights completes its phase and turns red, there’s always some delay).

Traffic signals give vehicles in each road entering the intersection time to proceed. They can work in isolation (common in areas where traffic lights are infrequent, traffic volumes are averagely low and the traffic flow is relatively balanced between all roads), or work in with other signals in the area (common in cities where groups of vehicles need to be shuffled between intersections, or one particular route should be given priority in order to move a large volume of traffic).

If they are isolated then they are controlled by vehicle loop detectors – loops of wire in the road that detect when a vehicle drives over them.

Coordinated signals are controlled by a central processor.

Red light cameras

Red light cameras will trigger if you enter the intersection when the light is red, but not if it is yellow.

Red light running is a problem because it causes accidents. Some drivers deliberately run red lights, while others misjudge the yellow light thinking they have time to get through. Chronic red light running at an intersection implies that something needs to be changed at the intersection. It could be that drivers are frustrated with the phase times, the lights are not easy to see (e.g. they are too low and frequently obscured by heavy vehicles), or the phasing at a previous set of lights encourages drivers to try to race between them.

Changes in phasing to a set of lights can cause temporary problems as drivers that frequently use that intersection get used to the new times. Often a sign will be placed near the intersection warning drivers that the phase has been changed.

Temporary traffic lights

Temporary traffic lights control traffic at roadworks. Stop behind the sign. If you park too far forwards, the sensor that detects you are there and triggers the lights to change might not register your vehicle.

Red lights at fire stations

If you see a red flashing light outside a fire station, this means stop as there will be a fire engine exiting to attend a fire.

Emergency vehicles

Emergency vehicles are allowed to pass through a red light if they are attending an incident and have lights and sirens operating.

Traffic signals run on a sophisticated system, called SCATS. This constantly assesses how many vehicles are travelling through the intersection in each direction. The system then adjusts the length of the green light to compensate. This ensures queuing and delays are minimised.

Many intersections are also linked to adjacent intersections along a major traffic route. The timing of the signals is then governed by creating the best traffic flow along the route.

You may regularly turn right at an intersection and ‘know’ that, for example, approximately six cars will get through on the green. However, at another time of day this will differ. And on a different day of the week this may also change, because traffic conditions have changed.

The system also gives priority to trams and buses at some intersections. While some motorists might not appreciate this, giving these mass-transit modes priority reduces congestion by encouraging people to use public transport. In some locations, pedestrians may also get a longer crossing time where many people cross, or slower pedestrians are present. This may also change the length of green time you receive at the intersection.

Red light arrow drop-out

Ever approach an intersection where the red-turn arrow switches off and no green-turn arrow is displayed? Don’t worry – it’s not a glitch!

In this scenario, the red arrow indicates that it’s not safe to turn just yet. When it drops out, it’s letting you know that you might be able to start turning, but you need to watch the remaining traffic lights and be mindful of oncoming traffic before you go. If the remaining light is green, you may start to turn right, just as you would at an intersection without arrow lights.

At some intersections once the arrow drops out there are no other traffic lights. In this case, you can start to turn after giving way to other road users.

Traffic lights at freeway entry ramps

Some freeway entry ramps are controlled by lights to make merging safer and easier by spacing out vehicles, known as ramp metering. Some operate 24/7, while others only switch on during peak-traffic times. Here’s how they work:

• When the lights start to operate, the yellow light flashes for around one minute.
• The lights then turn red for drivers on the entry ramp to stop at the stop line.
• The lights then begin their green, yellow and red cycle.
• The red traffic light means drivers must stop and not proceed until the light turns to green, just like standard red traffic lights at intersections.
• Only one vehicle can enter the freeway from each lane, unless signs state otherwise.
• Some freeway ramp signals allow trucks or vehicles with two or more people (T2/T3) to bypass the lights for priority access onto the freeway.

What to do when traffic lights are not working

First things first – don’t panic! When the lights are out, flashing yellow or just not working properly, simply approach the intersection with caution and courtesy, giving way to any vehicles approaching from the right. If you’re turning right, remember to give way to both oncoming traffic and traffic on your right.

When it’s safe to, you might also want to report the problem. You can do this by:

• locating the pale green or grey box at the side of the intersection and noting the intersection identification number
• calling VicRoads on 13 11 70 and quoting the identification number.

Do you stop or slow down at yellow lights?

Drivers’ behaviour suggests they think of the yellow light as an extension of the green, rather than as a warning to stop at the imminent red. A better way to think of the yellow is that it is at the start of the red, not at the end of the green.

A yellow light is not a signal to travel faster through the intersection to beat the red light. You must not travel through a yellow traffic light if you're able to stop safely before the stop line. If you can’t safely stop before the stop line, you must stop before entering the intersection itself.

If you’ve already entered the intersection when the light turns yellow or red, you must exit the intersection as soon as you can safely do so.

Keep in mind, just because you’ve crossed the stop line, does not necessarily mean you have entered the intersection. At this point, our recommendation would be that you stop.

Check out our Youtube video on Traffic Lights for more.

Anticipating light changes

RACV’s Drive School Manager, Peter Phillips, suggests that the “traffic and environment should be considered when deciding if it’s safe or not to stop. Learner drivers should exercise caution, learn to anticipate light changes and prepare to stop rather than prepare to race through”.

RACV receives many calls regarding red light camera infringements. Much of the time, the driver has decided they can continue through the intersection on the yellow light, misjudging either the traffic speed, the length of time it takes to get to the stop line or the length of the yellow light.

The trigger for a red-light camera is located just over the stop line and is activated 0.5 seconds after the yellow light changes to red. So in order to get a red-light camera fine, you have not stopped during the yellow and have gone through the red half a second too late.

Do not block the intersection

If the traffic ahead has not cleared the intersection or there is not enough room for your vehicle to reach the other side without blocking the intersection, do not enter the intersection.

By blocking the intersection, drivers delay traffic including emergency vehicles as well as risk substantial penalties.  Watch our video on blocking an intersection for further information.