Regulatory Signs Explained

The colour is the instruction, not the picture

A regulatory sign directs you to take, or not to take, a specific action, and failing to obey one is an offence. What catches learners out is that the picture tells you the subject and the colour tells you what you are being told to do about it.

A motorcycle on a blue disc and a motorcycle inside a red border are the same picture and opposite instructions. So are a number on a blue disc and the same number inside a red border — one is a minimum speed, the other a speed limit.

Read the colour first. Then the shape. Then the picture.

The seven groups of regulatory sign

Regulation 285 divides regulatory signs into exactly these seven, and the sign number tells you which group you are looking at.

The DoT learner manual calls the R500 family "selective restriction signs". The regulation calls the same family exclusive secondary signs. They are the same thing.

The colour code

The colour code in the official signs manual, set out group by group. It is the fastest way to read an unfamiliar sign.

Two things fall out of this. A control sign keeps its shape and colour whether it is permanent or temporary. And every other temporary sign goes yellow, which is why a yellow background says nothing about the subject of a sign — only that the situation is not normal.

Red border versus blue disc: the distinction the test is built on

A blue disc is a command or a reservation. A red border on a white face is a prohibition. Both are circular, and the symbol inside them is often identical.

Motorcycles only is a blue disc in the command series; no motorcycles is the same motorcycle inside a red border in the prohibition series. Buses only is blue; buses prohibited is a red border. Almost every vehicle class has a matched pair — minibuses, midibuses, delivery and goods vehicles, construction and abnormal vehicles, agricultural and animal-drawn vehicles, rickshaws, tour buses.

The pair that catches the most people is not a vehicle at all. A number on a blue disc is a minimum speed — do not drive slower than this. The same number inside a red border is a speed limit — do not exceed this. If you read the number and skip the colour you get it exactly backwards.

Why some prohibition signs have a diagonal slash and others do not

This is a rule rather than an accident, and it separates somebody who has learnt the system from somebody who has memorised pictures.

A prohibition sign that prohibits an action or an object carries a diagonal red slash across the symbol: no U-turn, no motorcycles, no left turn. One that states a limit — a maximum you must not exceed — carries no slash. Speed, mass, axle mass, height, length and width limits are all prohibition signs and none of them is slashed.

So a red border with a bare number is a ceiling on something you are measuring. A red border with a slash through a picture is a thing you may not do at all.

Control signs: the ones with their own shapes

Control signs are the small group that governs right of way. The stop sign and the no-entry sign were singled out long ago as the signs whose consequences are worst if they are missed, so they were given shapes nothing else on the road uses.

The stop sign is the only octagon. The yield sign is the only downward-pointing triangle. Those shapes do not change for a temporary version, and neither do the colours — a temporary stop sign is still a red octagon, not a yellow one. The group also holds the stop-yield sign, the three-way and four-way stop signs, no entry, the one-way roadway signs, pedestrian priority and yield to oncoming traffic.

Command versus reservation: mandatory versus conditional

Both are blue, and the difference is whether you had a choice about being there. A command sign is mandatory: it applies to you because you are on that road — keep left past the island, switch your headlamps on, proceed left only at the junction.

A reservation sign is conditional. It sets a lane, a roadway or a parking area aside for one class of vehicle, and using that facility is optional — but if the sign reserves it for buses, nobody who is not driving a bus may use it. The rule only reaches you when you try to use the thing it protects.

Comprehensive signs switch on a whole rule book

A comprehensive sign is one sign that brings several regulations into force at once, and you will meet three of them. Dual-carriageway freeway begins and single-carriageway freeway begins mean every freeway rule applies from that point — no pedestrians, no pedal cycles, no animal-drawn vehicles, no tractors, no hand signals, and no stopping except for a cause beyond your control.

The woonerf sign marks a residential street where pedestrians have right of way, through traffic is excluded, heavier vehicles are kept out and the speed limit drops to 30 km/h. One sign, four separate rules.

Narrowing a sign, and ending one

A rectangular sign mounted immediately beneath a regulatory sign is an exclusive secondary sign. It is never displayed on its own, it always takes the colours of the sign above it, and its job is to narrow that sign: two time periods, days of the week, daytime only, night time only, reduced visibility only, or one class of vehicle. Sign numbers written with a hyphen are these combinations.

The default matters as much as the exception. Unless a secondary message narrows it, a regulatory sign applies day and night, 24 hours every day.

Ending a restriction is a different job and it has its own sign. A de-restriction sign shows you the original sign again with a red cross laid over the face: from here, that rule no longer applies to you. You will see it most often at the end of a freeway and at the end of a woonerf.

There is one thing it may not do, and it is worth knowing because it looks like it should. A de-restriction sign may not be used to change a speed limit or a minimum speed. A change in speed limit is always shown by displaying the new speed limit sign, never by cancelling the old one.

Common questions