Joining a motorway and choosing your lane

Joining

The slip road exists to let you reach the speed of the traffic you are joining. Use all of it.

1. Look early. Start assessing the traffic on the motorway while you are still on the slip road, not at the end of it.
2. Build speed so that you arrive at the merge doing roughly what the left-hand lane is doing.
3. Check mirrors and blind spot.
4. Merge into a gap, adjusting your speed slightly rather than swerving.

Traffic already on the motorway has priority. Drivers often move over to help, and that is a courtesy rather than an obligation — do not plan around it.

Do not stop at the end of a slip road unless traffic is stationary. Joining from a standstill is far more dangerous than joining at speed.

Join the left-hand lane first. Crossing straight into the middle lane while still gaining speed puts you in front of faster traffic that has not planned for you.

Lane discipline

This is where most motorway irritation comes from, and the rule is simple:

Keep left unless you are overtaking.

The middle lane of a three-lane motorway is not a cruising lane, not a lane for “people doing 60”, and not a way of avoiding merging traffic. It is an overtaking lane, and so is the right-hand lane.

Sitting in it when the left is clear:

• wastes a third of the road’s capacity;
• forces other drivers to make more lane changes than necessary;
• is an offence in its own right.

Once you have completed an overtake, check your mirrors and blind spot, and move back to the left.

Some vehicles are not permitted in the right-hand lane of a motorway with three or more lanes: vehicles towing trailers, goods vehicles over 7.5 tonnes, and long or heavy passenger vehicles.

The signals above you

Gantry and verge signals are the motorway talking to you about something you cannot see yet.

• Flashing amber with a speed — hazard ahead. Slow to the speed shown and stay alert until a signal tells you the road is clear.
• A speed in a red circle — a mandatory, enforceable limit.
• Red X — that lane is closed. Move out as soon as it is safe. There is a broken-down vehicle, debris, an incident or people working in it. Cameras enforce this, but the real reason is that you cannot yet see what is there.
• Red flashing lights and a red X across all lanes — stop.

Why it matters

Motorways are statistically the safest roads in the country, and the reason is predictability: everyone travelling the same way, at similar speeds, with no junctions or pedestrians.

Almost everything that goes wrong on one is a break in that predictability — a hesitant merge, a sudden lane change, a car sitting in a closed lane. Lane discipline is not etiquette. It is what keeps the system working.