Traffic lights and box junctions

By the end of this topic you can

• You can say what each colour and arrow means for drivers.
• You can approach lights at a speed that lets you stop if they change.
• You can decide correctly whether to stop or go on amber.
• You can use a yellow box junction legally, including when turning right.
• You can deal safely with lights that are not working.

What you need to know and understand

• Red means stop behind the stop line.
• Amber means stop, unless you are so close to the line when it appears that stopping would be dangerous.
• Green means go on if the way is clear. It is not a right of way, and you still give way to pedestrians crossing when you turn.
• A green arrow lets you go in the direction of the arrow if safe, even if a red light is also showing.
• Do not enter a yellow box unless your exit is clear. You may wait in it to turn right if only oncoming traffic is stopping you.
• There is no turning left on red in Ireland unless a green or flashing amber left arrow allows it.
• Failing to obey traffic lights carries 3 penalty points on payment of the fixed charge.

The light sequence and what it asks of you

• Red: stop. Do not pass the stop line, or the light if there is no line.
• Amber: stop at the line unless stopping would be dangerous.
• Green: go if the way is clear, taking care when turning.
• Green arrow (filter): you may go in that direction only, if safe.
• Flashing amber arrow pointing left: you may go, but first give way to traffic and to pedestrians and cyclists crossing.
• Flashing amber at a pelican crossing: give way to pedestrians on the crossing, then go when it is clear.

Yellow boxes: keep the junction moving

A yellow box is a grid of criss-cross yellow lines. It keeps the junction clear so traffic in other directions can move. Before you enter, look at the road beyond: if there is not room for your whole car on the far side, wait behind the box even when your light is green.

The one exception is a right turn. You may wait inside the box for a gap in oncoming traffic, as long as you do not block traffic that has right of way. Entering a box wrongly is a fixed charge offence.

When the lights are out

If the lights at a junction are out of order, the Rules of the Road says you must first stop at the stop line. Then go only when it is safe, giving way to traffic with right of way, and expect other drivers to be unsure. If a Garda is directing traffic, the Garda's signals override any lights.

Turning right at lights

On green, move forward into the junction without blocking oncoming traffic, and finish the turn when there is a safe gap. Only wait for a right filter arrow once you are in the junction if finishing the turn before it appears would be dangerous. When a right arrow lights, you may complete the turn if it is safe, but still check for pedestrians and anyone running a late amber.

Common mistakes

• Speeding up when the light turns amber. Approach every set of lights ready to stop.
• Moving off because the lane beside you got a green arrow. Follow only the signal for your lane.
• Following a queue into a yellow box and getting stuck across the junction.
• Turning left on a green light without checking for pedestrians crossing the side road.
• Treating a broken set of lights as a free-for-all. Stop first, then go with care.

Test yourself: Traffic lights and box junctions

Answer each question, then read the explanation. Questions come in a random order each time.

Go deeper

• Traffic Lights, Driver Signals and Hand Signals in Ireland
• Irish Road Markings