Traffic lights

Traffic lights: Need to know

Guide to traffic lights for beginners



STOP. If you’re about to learn to drive, traffic lights are among the first road signals you’ll be taught. While quite a straightforward signal, they’re important to get right. Not only are they common in day-to-day driving, but they feature in the driving test – both the theory and the practical.

Here, BSM tells you everything you need to know about traffic lights. Ok, let’s GO!


What are traffic lights for?

By displaying a red light, traffic lights signal to a driver when they should stop. When they turn to green, it’s safe to go again. Their purpose is to manage the flow of traffic, and let road users know when it’s safe to cross the path of other vehicles.

Most traffic lights also have an amber light, which we’ll explain further below. Traffic lights can be fixed, such as at busy junctions; or temporary, such as at roadworks.


Where do you stop at a traffic light?

Fixed traffic lights will have clearly marked lines where you should stop. Many traffic lights have two lines, and a differently coloured box for cyclists. Other vehicles should avoid coming to a halt in this box.

Temporary lights tend not to have lines, so road users should use their judgment to stop at a distance where it’s safe to pull off afterwards.


Is it illegal to go through a red light?

Yes, it’s against the law to go through a red light. Not only that, it’s dangerous, and could easily lead to an accident. Running a red light puts you directly in the path of other road users. Even if there appears to be no other traffic, you need to stop at a red light. Sometimes, traffic might appear from a direction you might not expect. Plus traffic lights may be fitted with cameras for enforcement.


How do traffic lights work?

Most traffic lights in the UK follow a pattern known as the traffic light sequence. It goes as follows:

  • Red light: Stop
  • Red & amber lights: Prepare to go
  • Green light: Go, if the way is clear
  • Amber light: Stop, provided it’s safe to do so

What do I do at a red light?

On approaching a red light, stop behind the line. All road users including cyclists must do this. Put your vehicle in neutral and apply the handbrake, unless you think the wait will be short.


What if the light is red and amber?

This means the lights are about to change from red, so you should prepare to go. If you’re at a halt, put the car in gear and release the handbrake. Don’t cross the line until the light goes green, however.


What do I do at a green light?

Although green means go, you should always use your judgment, and check the coast is clear. It’s important to be mindful of other road users at all times.


What if the light is amber?

Amber usually means stop, unless it’s unsafe to do so. If you’re too close to the line at the time the light turns amber, you may be committed, and braking sharply could lead to an accident. Technically it’s legal to go through an amber light, but ideally you shouldn’t do this unless you have to.

If the traffic lights are at a pedestrian crossing, the lights tend to flash amber before turning green. This means you can proceed if the crossing is clear. If pedestrians are still crossing, wait until it’s safe to go.


What do traffic lights with arrows mean?

Traffic lights with green arrows pointing left, right or straight ahead are called filter traffic lights. These let road users in different lanes know when it’s safe for them to go, and they get priority. For instance, if the light for straight ahead is red, but the left-hand arrow is green, then those turning left can go.

In addition, if the right-hand arrow is green, it’s safe for you to turn right. Traffic coming in the other direction will be halted, so you won’t need to give way.


Are there any driving test traffic light tips?

On your driving test, anticipating the lights will demonstrate you’re reading the road correctly. For instance, if a light has just turned red, you know you’ll be waiting for long enough to put the car in neutral and apply the handbrake. Or if you’re approaching a light that has been green for a long time, it’s worth slowing down, as there’s a better chance it will turn red soon.

Also, don’t forget to apply the mirror, signal, manoeuvre routine before pulling away – even at traffic lights.