Breaking down on a motorway: the procedure that protects you, not the car

The most dangerous part of a motorway breakdown is not the breakdown. It is the first five minutes after stopping, when driver and passengers behave the way they are used to behaving on a town street.

The first seconds

Hazard lights on immediately — before you start moving across.

Do not brake hard. The car behind is not expecting a sudden deceleration, and at motorway speeds that ends in an impact.

Move left smoothly, using your momentum. If the engine has stopped you have a limited reserve of speed — spend it on getting off the carriageway, not on trying to restart.

An important detail: with the engine off, brakes and steering become heavy. The brake servo holds a reserve for a few applications; power steering disappears at once. That is not a fault, but you have to be ready for it.

Get as far off as possible — onto the hard shoulder, into a refuge, behind the barrier where that is possible.

Which side to get out

The central rule here, and it is counterintuitive.

Get out through the doors away from traffic. The offside doors open straight into the running lane.

Everybody gets out, passengers included.

Go behind the barrier or up the embankment, away from the carriageway.

Do not sit in the car on a motorway shoulder — it is the most dangerous place available. Vehicles stopped on the hard shoulder are struck from behind regularly.

Put hi-vis vests on before getting out, not after.

Warning triangle and visibility

Place the triangle at the distance your local rules specify — on a motorway that is noticeably further than in town.

Walk with the triangle along the verge facing the traffic, never on the carriageway.

At night and in fog this is the most critical part: without a vest and a torch a person on the verge is invisible.

When you can drive on

This is where distinguishing symptoms beats acting blindly.

Do not drive on:

• Oil pressure light — stop the engine immediately; it destroys itself in tens of seconds.
• Overheating — next comes the cylinder head; covered in the overheating article.
• Brake warning light with the handbrake down.
• A knock from the engine.
• Smoke from under the bonnet or a burning smell.
• Damaged wheel or suspension.

You can drive on carefully:

• A steady Check Engine light with no change in how the car drives.
• An ABS light — the brakes work, distances are longer.
• Slight power loss with no knocking or smoke.

Do not drive with a flashing Check Engine — those are active misfires destroying the catalyst right now; covered in the misfire article.

Warning light priorities are covered separately in the dashboard lights article.

What a scanner gives you at that moment

This is exactly the situation an adapter is carried for.

Read the code — and know whether this is “drive to a workshop” or “call recovery”. The cost difference runs both ways: an unnecessary recovery costs money, driving on an overheated engine costs an engine.

Look at the temperature — the real one, not the needle, which on many cars is damped and reads “normal” until the last moment.

Look at the voltage — alternator or battery; that decides how far you will get; covered in the alternator article.

Save the freeze frame — so you can tell the mechanic the conditions it happened under.

The full procedure

1. Hazard lights.
2. Smoothly off the carriageway, as far from traffic as possible.
3. Vests on inside the car, before opening a door.
4. Exit away from traffic, everybody behind the barrier.
5. Triangle at the required distance, walking along the verge.
6. Assess — code, temperature, voltage.
7. Decide: drive on, or call for help.

In short

• Hazards go on before the manoeuvre, not after stopping.
• With the engine off, steering goes heavy at once and brakes after a few applications.
• Exit away from traffic and get behind the barrier; the shoulder is a dangerous place.
• Oil pressure and overheating mean stop, not “I will make it”.
• A code and a temperature turn a guess into a decision.

Download the app — codes, temperature, and voltage are read with an ELM327 adapter over Bluetooth SPP on Android, right at the roadside.