Traffic Signs Manual/Chapter 3/2008/18

18LANE CONTROL SIGNALS AND SIGNS FOR TIDAL FLOW

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LANE CONTROL SIGNALS

5001.1 Lane open to vehicular traffic

5001.2 Lane open to vehicular traffic
(Alternative type)

18.1 The signals shown in Part I of Schedule 10 to the Regulations are used on single carriageway roads where a tidal-flow system is in operation, e.g. where a high proportion of the flow is in one direction during the morning peak hours, with the major flow in the reverse direction during the evening peak. This form of control permits the higher traffic flow to use a greater width of the carriageway by reversing the traffic flow in one or more central traffic lanes at different times of the day. The "red cross" signals shown in diagrams 5003 and 5003.1 are also prescribed for use on actively—managed hard shoulders of motorways (SI 2005 No. 1670, the Traffic Signs (Amendment) Regulations and General Directions 2005), but this application is not considered here. Lane control signals may be used only to indicate the effect of an order (direction 7).

18.2 Figure 18-1 shows the basic arrangement for placing the signals above the carriageway. Regulation 44(2) requires that the height of the centre of each light signal from the surface of the carriageway in the immediate vicinity shall be not less than 5.5m nor more than 9 m. Each signal is prescribed with maximum and minimum dimensions. Regulation 12(6), which requires the shape and proportions to remain the same when choosing dimensions for individual elements of a sign, does not apply in this case. This allows more flexibility when designing each signal. The overall size of each signal will depend on the speed of traffic, not just at peak times, but during free—flow conditions, as the signals are in use at all times. Although figure 18.1|18-1 shows five lanes, tidal flow can be used in other situations, such as on a three-lane carriageway.

Figure 18-1 Example of lane control signals mounted above the carriageway for a tidal-flow system

18.3 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.

5003 Lane closed to vehicular traffic

5003.1 Lane closed to vehicular traffic
(Alternative type)

18.4 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.

5005 Lane closed ahead and vehicular traffic should move to the next lane on the left

5005.1 Lane closed ahead and vehicular traffic should move to the next lane on the left
(Alternative type)

18.5 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.

18.6 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 of all traffic. For those lanes where the direction of flow is never changed, the green arrow and red cross, as appropriate, will be permanently displayed. These signals must be internally illuminated and identical to those displayed above the tidal—flow lane.

LANE CONTROL SIGNS

5010 Lane control light signals ahead

The white arrow symbol and the words "move to left" shall be omitted where signals to diagram 5005 or 5005.7 are not used in the lane control system

5011 Lane control light signals on a road extending from a junction ahead

The white arrow symbol and the words "move to left" shall be omitted where signals to diagram 5005 or 5005.7 are not used in the lane control system

5012 System of lane control light signals ahead

5013 Direction of a system of lane control light signals

The arrow may be reversed

5014 Distance to and direction of a system of lane control light signals
(Alternative types)

The distance may be varied (see Appendix B).
The arrow may be reversed or omitted

18.7 The signs shown in Part II of Schedule 10 to the Regulations are used to inform drivers of a tidal—flow system ahead and to explain the meaning of the lane control signals. The x—height of these signs may be varied from 75 mm to 150 mm and depends on the speed of traffic. Appropriate sizes are specified in Appendix A.

18.8 A sign to diagram 5010 is used on a road that leads directly into a tidal—flow system. It gives advance warning of lane control on the road ahead, and explains the meaning of the signals. The white arrow symbol and the legend "move to left" is omitted where the signal to diagram 5005 or 5005.1 is not used. The sign should be sited approximately 200 m before the first signal. A sign to diagram 5012 should be sited between 50 m and 100 m before the first signal. A sign to diagram 5014, omitting the arrow, and varied to indicate the distance to the nearest ten yards, should be sited approximately 400 m before the first signal. Where the 85th percentile speed of traffic is above 30 mph, an additional sign to diagram 5010 might be required. In this case it should be sited 400 m before the first signal, with the sign to diagram 5014 located approximately 800 m before the first signal. Where the road is one way or a dual carriageway on the approach to the tidal—flow section, a sign to diagram 5010, 5012 or 5014, as appropriate, should be provided on each side of the carriageway at each location.

18.9 The sign to diagram 5011 is similar to diagram 5010, and is used on a side road that joins a major road within a lane control section. The sign should be placed at least 50 m from the junction to enable drivers to assimilate the information on the sign before diverting their attention to the junction ahead. Where the side road is one way (with two or more lanes) or a dual carriageway, the sign should be provided on each side of the carriageway. Where a side road joins a major road prior to the start of the lane control section, a sign to diagram 5011 should be provided if drivers would not pass a sign to diagram 5010 after turning into the major road. In this case, the sign should be supplemented by a sign to either diagram 5013 or 5014 located at the junction and with the arrow pointing in the appropriate direction. Signs to diagrams 5013 and 5014 may be used on their own where drivers, after turning into the major road, pass a sign to 5010 but not the sign to diagram 5014 without the arrow (see para 18.8).

5015 End of a system of lane control light signals

18.10 A sign to diagram 5015 should be provided on each side of the road where the lane control signals end. Alternatively, the sign may be located above each lane that is available to traffic travelling away from the lane control section.

This work has been mirrored or sourced from material provided on the UK Government website at https://www.gov.uk/government/publications/traffic-signs-manual, which states material is available under the terms of the Open Government License unless indicated otherwise. (Crown copyright acknowledged.)

This is NOT an official transcription, and should NOT be considered in any way a controlled copy of the work in question.

This document no longer necessarily represents current practice, as it relates to an earlier version of the regulations (TSGRD 2002 as amended at publication date) rather than the current TSRGD 2016 regulations. It should not be used for actual design or operational use without consulting a more recent edition.

This version was transcribed in May 2015, from a 2008 impression.