Drivingo

Road signs

Motorway Signs and Signals: Red X, Amber Flashes and Smart Motorway Rules

Published

The one motorway signal you can never ignore is the red X: it means the lane is closed, and driving in it is against the law. Around it sits a small system of signals and blue signs that tells you everything from where the motorway starts to how far the next exit is.

Here's the full set, in the order you meet them on a real journey.

What does the start of motorway sign mean?

Start of motorway and point from which motorway regulations apply

The white motorway symbol on blue marks the start of a motorway and the exact point where motorway regulations begin: no pedestrians, cyclists, horse riders, learner car drivers without a full licence, or slow vehicles. If you're not allowed on a motorway, this sign is your last warning.

Blue is the motorway colour throughout. Junction signs leading onto a motorway carry the same white-on-blue style:

At a junction leading directly into a motorway (junction number may be shown on a black background)

What do overhead gantry signals mean?

Modern motorways, especially smart motorways, use overhead electronic signals. One signal can apply to the whole carriageway, or each lane can have its own sign above it.

The Highway Code, Rule 256: A single sign or signal can display advice, restrictions and warnings for all lanes. Lane specific signs and signals can display advice, restrictions and warnings that apply to individual lanes.

The three signals to know cold:

  • A speed limit in a red circle is mandatory, not advisory. You must not exceed it.
  • Amber flashing lights warn of a hazard ahead: slow down and be ready, and don't speed up until you pass a signal that's clear.
  • A red X means the lane is closed.

The Highway Code, Rule 258: Red flashing light signals and a red ‘X’ on a sign identify a closed lane in which people, stopped vehicles or other hazards are present. You

MUST follow the instructions on signs in advance of a closed lane to move safely to an open lane

MUST NOT drive in a closed lane. A sign will inform you when the lane is no longer closed by displaying a speed limit or the word ‘END’. Be aware that

  • there can be several hazards in a closed lane
  • emergency services and traffic authorities use closed lanes to reach incidents and help people in need
  • where the left lane is closed at an exit slip road, this means that the exit cannot be used. Where red flashing light signals and closure of all lanes are shown on a sign, the road is closed. You

MUST NOT go beyond the sign in any lane or use the hard shoulder to avoid the road closure unless directed to do so by a police or traffic officer. Lane and road closures indicated by red flashing lights are enforced by the police. Laws RTA 1988 sects 35 & 36 as amended by TMA sect 6, TSRGD reg 3 and sched 15, MT(E&W)R reg 9 & MT(S)R reg 8.

Red X questions are near guaranteed in the theory test, and the answer is always the strict one: get out of the lane as soon as it's safe, never use it to jump the queue, and never drive under a red X even if the lane looks empty. Closed lanes protect stopped vehicles and people.

How do you know where your exit is?

Direction signs on motorways count you down. A mile before the junction you'll see the exit sign with destinations; panels with an inclined arrow list the places reachable by leaving at the next junction:

The panel with the inclined arrow indicates the destinations which can be reached by leaving the motorway at the next junction

Then come the countdown markers: three bars, two bars, one bar, each bar meaning 100 yards to the start of the slip road.

‘Countdown’ markers at exit from motorway (each bar represents 100 yards to the exit). Green-backed markers may be used on primary routes and white-backed markers with black bars on other routes. At approaches to concealed level crossings white-backed markers with red bars may be used., desc: ough these will be erected at equal distances the bars do not represent 100 yard intervals.

Three bars means 300 yards to go. If you're in the wrong lane at the countdown markers, carry on to the next junction rather than cutting across.

What does the end of motorway sign mean?

End of motorway

The crossed-out motorway symbol means motorway regulations end ahead. Expect a change: lower speed limits, two-way traffic, roundabouts, and road users who aren't allowed on motorways. Check your speed; after miles at 70 mph, 40 feels like walking pace.

What are emergency diversion symbols?

If a motorway closes, diversion routes are marked with simple black-on-yellow shapes: a square, triangle, circle or diamond.

Symbols showing emergency diversion route for motorway and other main road traffic

Follow the shape shown at the closure and it leads you along the diversion back to the motorway. The shapes exist so several diversion routes can overlap without confusing anyone: you just follow your symbol.

Motorway signals in the theory test

Expect questions on the red X, amber flashing signals, countdown markers and the start and end of motorway regulations. They're all rule-based, so this is another topic where marks are simply collected.

Every motorway signal and sign in the official syllabus is in Drivingo's practice bank, with explanations linking each answer to the rule behind it. Download Drivingo and lock in the motorway questions before test day.

Contains public sector information licensed under the Open Government Licence v3.0.

Ready to see if you'd pass today?

Practise every official question with clear explanations and realistic mock tests — free to download.

Download on the App StoreGet it on Google Play