If you see countdown markers then you should be aware that you are approaching a junction and a potential hazard. When you see countdown markers with a white background and red distance marker stripes, then you should be prepared to stop as they indicate you are approaching a concealed level crossing.
These signs give you an early warning that you may need to stop at a barrier for a level crossing that you cannot yet see. Typically these signs are used before a bend after which level crossing barriers may cross the road. The sign with 3 red stripes indicates you are 300 yards from the concealed crossing. 2 stripes indicates you are 200 yards from the crossing and one stripe indicates you are approaching the last 100 yards before the crossing.
When else would you see countdown markers?
Countdown markers indicate that you are 300 yards from the end of something. Depending on their colour, you will know what will happen after the 300 yards is complete:
Blue background with white stripes
You will see these when approaching the end of the motorway or as you approach a motorway junction.
Green background with white stripes
You will see these when approaching the end of a dual carriageway or as you approach a junction.
White background with red stripes
You will see these less frequently. They indicate you are approaching a concealed level crossing.
Theory Test Question
Have you tried answering the question: Where will you see these red and white markers? Let’s take a look at each of the responses to help you check your learning.
Approaching the end of a motorway
Wrong! The signs that indicate you are approaching the end of the motorway will be blue like any other motorway sign. You will see countdown markers like these but they will have a blue background and white distance stripes. The end of a motorway will also be indicated by a sign of a motorway with a red cross through it.
Approaching a concealed speed-limit sign
Wrong! There is not a sign to indicate you are approaching a concealed speed-limit sign.
Approaching a concealed level crossing
Correct! Sometimes a level crossing may be found around a bend or something else that conceals it from view. These specific countdown markers should alert you to the fact that you are approaching a level crossing that you might not yet be able to see.
Approaching the end of a dual carriageway
Wrong! Whilst you will see countdown markers when you are approaching the end of a dual carriageway, these will have a green background and white distance stripes. You may also see a red triangular sign warning you that the dual carriageway is ending.
References
Page 27 of Know your traffic signs states:
Countdown markers may be provided on the approach to a crossing. These divide the distance between the advance warning sign and the stop line into three equal parts; each sloping bar does not necessarily represent a distance of 100 yards.