What a command requires
Command signs specify an action or the road users allowed to use a road. Keep-left/keep-right signs tell you which side of an obstruction to pass. Proceed-left/right/straight signs control the movement at the decision point; turn-left/right signs direct a turn. Read the actual arrow instead of assuming that every arrow has the same scope.
A minimum-speed sign sets the indicated minimum in circumstances where it is safe to maintain it; it does not authorise exceeding a maximum limit or driving too fast for hazards. The minimum-mass command restricts use to vehicles exceeding the indicated mass. It is the opposite of a maximum-mass prohibition.
Road-user symbols on circular command signs reserve use for the indicated class: pedestrians, cyclists, their shared or separated facilities, motorcycles, cars, taxis, minibuses, midibuses, buses, delivery and goods vehicles, construction vehicles, dangerous-goods or abnormal vehicles, rickshaws, tour buses, agricultural and animal-drawn vehicles. Combined bus symbols admit only the classes pictured.
- For the pedestrian/cycle combinations, distinguish a shared area from separate sides shown by a dividing line. Keep to the side assigned to your class.
- The toll command requires payment of the applicable toll; the headlamp command requires headlamps to be switched on. A daytime running lamp is not a reason to ignore a headlamp instruction.
- The roundabout command requires clockwise travel around the central island; use the accompanying yield control to decide priority.
Read the unit and the thing being limited
Maximum-speed signs limit speed; gross-mass signs limit the vehicle’s GVM or GCM; axle-mass signs limit axle mass; and height, length and width signs limit those dimensions. These limits protect road structures or space. A vehicle that fits under a height limit may still exceed an axle-mass or width limit.
Before entering a restricted road, compare the displayed limit with the applicable vehicle rating or dimension. At a gross-mass restriction, check GVM or GCM rather than merely the load currently carried. A roof load affects height, projecting loads affect dimensions, and vehicle combinations require particular care. If you cannot establish that the vehicle complies, choose a suitable lawful route before reaching the obstruction.
- A circular speed limit of 60 is a maximum, not a target. Reduce further for poor visibility, pedestrians, bends or an uneven surface.
- The goods-vehicle mass restriction prohibits the indicated class exceeding its stated GVM threshold; do not confuse gross vehicle mass with the load presently on board.
A prohibition removes an option
No-turn signs may prohibit a turn at the sign or a turn ahead: read the arrow and the position of the sign before committing. A U-turn prohibition removes the option of turning back even when there seems to be space. Overtaking prohibitions apply for their signed extent and may be limited to the vehicle class indicated.
No parking and no stopping have different effects. A no-stopping restriction prevents voluntary stopping as well as parking; a no-parking restriction does not permit leaving the vehicle merely because the engine is running. Read time plates and road markings to determine the extent and times.
The prohibited-class series covers pedestrians, cycles and their combination, motorcycles, cars, taxis, minibuses, midibuses, buses, delivery/goods vehicles, construction and dangerous-goods vehicles, abnormal vehicles, rickshaws, tour buses, agricultural/animal-drawn vehicles and horses with riders. A crossed-out or red-bordered class restriction is not a reserved lane for that class.
- The excessive-noise sign limits noise; the no-hitch-hiking sign prohibits hitch-hiking; and the unauthorised-vehicles sign restricts entry to authorised vehicles.
- The towed-vehicles-prohibited sign excludes that movement, and the no-hawking sign prohibits hawking. Check the symbol and any local plate rather than applying a rule to every road user.