Page:UK Traffic Signs Manual - Chapter 3 Regulatory Signs. 2008 (Second Impression 2008).pdf/159

 A signal to diagram 5001.1 or 5001.2 is placed above a traffic lane facing the direction of oncoming vehicles to indicate that traffic in the lane below the green arrow may proceed beneath or beyond that arrow.

A signal to diagram 5003 or 5003.1 is placed above a traffic lane facing the direction of oncoming vehicles to indicate that traffic in the lane below the red cross must not proceed beneath or beyond that red cross.

A signal to diagram 5005 or 5005.1 indicates that traffic should move to the next lane to the left as soon as it is safe to do so. It is normally used at the start of a tidal—flow system to direct traffic away from an opposing tidal—flow lane. The signal will also be needed when closing a tidal—flow lane, so that a green arrow first changes to a white arrow before changing to a red cross. However, depending on the road layout there might be situations where it is not required in one particular direction.

The signals should be mounted back to back centrally over a traffic lane to face both directions along the lane, so that whenever the green or white arrow facing traffic from one direction is showing, the red cross facing the opposite direction is also showing over the same traffic lane. When changing the direction of flow, the lane first needs to be closed with the red cross showing in both directions for a period long enough to ensure that the lane is clear 157