Who may not use a motorway
Learner permit holders, pedestrians, cyclists, animals, and vehicles under 50cc. All of them, all of the time.
Joining
Use the full length of the slip road to match your speed to the traffic already on the motorway, then merge into a gap. Motorway traffic has priority — do not expect it to move over for you, and do not stop at the end of the slip road unless traffic is genuinely stationary.
Lane discipline
Drive in the left-hand lane and use the others only to overtake. Sitting in a middle or right lane when the left is clear obstructs traffic and is an offence, not merely bad manners.
The hard shoulder
Emergencies and breakdowns only. Not for a phone call, not for a rest break, not to overtake.
If you break down: get everyone out of the vehicle on the side away from traffic, and behind the barrier. The hard shoulder is statistically the most dangerous place on the motorway, and sitting in a stationary car on it is worse than standing clear of one.
Following distance
Two seconds in the dry, four in the wet, more on ice. At 120 km/h, two seconds is roughly 67 metres — far more space than most people leave.
If you miss your exit
Carry on to the next junction and come back. Reversing on a motorway, or crossing the central reservation, is extremely dangerous and illegal.
Signals overhead
A red X above a lane means that lane is closed — move out of it. Driving through one is an offence, and there is usually a crashed vehicle or a work crew behind it.
Countdown markers show the distance to the exit: three bars at 300 metres, two at 200, one at 100.