Traffic Lights and Signals

Every signal, and what it requires

A traffic signal is a road traffic sign in law — one that, by automatic light signals, alternately directs traffic to stop and permits it to proceed. These are the actions the Department of Transport sets out for each.

The regulations call the middle light yellow; everybody on the street calls it amber. Same light, either word.

Amber: the question the test is actually asking

Amber means stop. That is the instruction, and the only exception is that stopping cannot be done safely.

It is worded that way round on purpose. The exception is about whether you can stop — whether you are so close, or the vehicle behind you is so close, that braking would cause a crash. It is not about whether you would rather not.

Which is why the classic wrong answer is "accelerate to get through before it turns red". A driver who speeds up at amber has turned a stopping decision into a speed decision, and arrives at the intersection faster at exactly the moment cross traffic is about to be released. Decide at amber whether you can stop, and stop if you can.

The layout and the sequence

A traffic signal is arranged vertically: the topmost light is red, the central light is yellow and the lowest is green. Any of the three may be more than one lamp side by side, but the order never changes — which is what lets a colour-blind driver read a signal by position.

The prescribed basic sequence is red, green, yellow, red. Read that carefully, because it says something about South African signals that surprises drivers who learnt elsewhere: the light goes from red straight to green. There is no intermediate phase warning you that green is coming, so there is nothing to pull away on. Every flashing signal, meanwhile, flashes at between one and two flashes per second, the same for every flashing aspect on the road.

When the signal is dark, or out of order

This is the situation South African drivers meet most often and guess at most freely, and the regulations answer it directly. Where no light signal is illuminated at all on your approach to a signalised junction, you act as for a three-way or four-way stop sign. That means stopping, and then going in the order everybody arrived — the vehicle that stopped first moves off first.

An out-of-order signal is put into one of two states on purpose. Either all the lights go dark, or every vehicular red flashes while the pedestrian and cyclist signals are switched off. Both mean the same thing for you: stop and take your turn.

There is also a sign for it: a cross-shaped hazard marker reading traffic signals out of order, attached to the signal or placed ahead of it. Slow down, yield, and look for a traffic officer or a stop sign controlling the junction instead.

Flashing red, and the two at a railway crossing

A flashing red signal is a red disc, and it means stop and then proceed when it is safe, exactly as at a stop sign. It does not mean slow down and look.

At a railway crossing the arrangement is specific: two red lights below the stop sign and above the railway hazard marker, on the near side of the crossing and on the left of each approach, illuminated in an alternating flashing mode only when a train is approaching. So a crossing with dark lights is not a broken crossing — and while they are flashing you may not proceed at all, which makes this the one flashing red that is not "stop, then go when clear".

Arrows, and the lights above the lane

An arrow signal controls one movement rather than the whole approach. A steady green arrow shows the direction traffic must take; a flashing green arrow gives you right of way in the direction it points; a steady amber arrow means stop and wait for the flashing green.

A flashing red left arrow — stop, then turn if the way is clear, giving way to pedestrians, to oncoming traffic turning right, and to traffic coming through from your right — is still described in the Department of Transport's learner manual. It is worth knowing that the regulations provided it should not be displayed after 31 December 2010, so it is a signal on the way out rather than one to expect.

Overhead lane control signals are a separate system, used where a lane reverses direction at different times of day. A steady green downward arrow over a lane means you may drive in it. A steady red cross means you may not, and the lane may be carrying traffic the other way. A yellow arrow means your lane is closed ahead and you must leave it in the direction it points.

What beats what at a signalised junction

Signals, signs, markings and a person in uniform can all be present at the same intersection, and the regulations set out the order of precedence.

A sign that prohibits or prescribes a directional movement beats a light that permits right of way. A green light is permission to proceed, not permission to turn — if a no-right-turn sign is up, the green does not authorise the turn. A light that permits right of way, in turn, beats the stop line, which is why you do not stop at the painted line while the light is green.

Above all of it sits the traffic officer. The Act requires compliance with a road traffic sign unless otherwise directed by a traffic officer, so an officer's hand signal overrides the signal, the sign and the paint alike.

Pedestrian signals, and the driver's side of them

A pedestrian signal has two lights, red above and green below. A pedestrian at a crossing controlled by a signal may not enter it except in accordance with that signal. The flashing red figure is the one people misread: it does not mean run. Anyone who has not yet stepped into the road waits for the next green figure; anyone already crossing finishes as quickly as they can.

From the driver's seat, two things follow. A flashing amber disc lets you drive on carefully but you still yield to pedestrians. And wherever a vehicle has stopped at a pedestrian crossing to let people cross, a driver approaching from behind may not pass it — the stopped vehicle is hiding somebody.

Common questions