An Introduction to the Use of Portable Vehicular Signals March 2008 7611 Introduction to the Use of Portable Vehicular Signals v4_2.
This booklet is for people with specific responsibility for portable vehicular signals at street works and road works. Sites with alternate one-way vehicular flows are referred to as ‘shuttle’ working. For current information about traffic control at street works and road works, including health and safety issues, you, or your supervisor, should refer to Chapter 8 of the Traffic Signs Manual and to Safety at Street Works and Road Works: A Code of Practice.
An Introduction to the Use of Portable Vehicular Signals London: TSO 7611 Introduction to the Use of Portable Vehicular Signals v4_2.
Department for Transport Great Minster House 33 Horseferry Road London SW1P 4DR Web site www.gov.uk/dft © Queen’s Printer and Controller of Her Majesty’s Stationery Office, 2008, except where otherwise stated. Copyright in the typographical arrangement rests with the Crown. You may re-use this information (not including logos or third-party material) free of charge in any format or medium, under the terms of the Open Government Licence. To view this licence, visit www.nationalarchives.gov.
Introduction This booklet does not cover portable pedestrian crossing facilities. See Traffic Advisory Leaflet 3/11: Signal-controlled pedestrian facilities at portable signals for advice on the use of these facilities. The leaflet is available from the Department’s website at www.gov.uk/government/publications/signal-controlled-pedestrian-facilities-at-portable-traffic-signals You, or your supervisor, will need to discuss the placing of portable traffic signals with the traffic authority.
The system Signal heads: the Code of Practice says that consideration should be given to providing two signal heads on each approach. However, whether one or two signal heads are used, for safe operation, the approaching driver must be able to see at least one signal on the approach and one whilst waiting at the WAIT HERE sign (see ‘Setting up the equipment’). Signal heads must be either: compliant to the European Specification EN 12368, or of a type approved to TR 2206, or the TR 0102 amendment to BS 505.
What to do first The portable signal controller and detector equipment must be of a type approved on behalf of the Secretary of State for Transport. Specifications are issued by the Highways Agency. Look on the controller for a label* for the specification reference. Most equipment will be approved against MCE 0111, TR 0111, or the current TR 2502. Equipment to MCE 0111 and TR 0111 has the same initial set-up (see pages 15 and 16), whereas that to TR 2502 is different.
Vehicle Actuation (VA) operation Signal control should always be vehicle actuated (VA) unless agreed otherwise, in writing, by the traffic authority. You will find that modes other than VA are provided on the controller, but these should only be used to relieve short-term difficulties. VA reduces delay to vehicles by ensuring that the green time is adjusted automatically.
Vehicle Actuation (VA) On VA, if there are no approaching vehicles, the signals will revert to red in both directions. The first vehicle to arrive will register a demand for the signals to change on that approach. See ‘Nudge circuit’ on page 14. Following vehicles will extend the time that the green light is shown. The duration of the green will vary between the minimum green period (7 or 12 seconds) and the maximum green period (settable on the controller).
What you need to do Use only equipment of a type approved (a legal requirement) – see page 3. All equipment on site can have problems, particularly from accidental and vandal damage. Maintenance contact information is therefore essential and should be readily available – for example, prominently displayed on the equipment. Test the equipment before setting up – see pages 14 to 16. Set up the signing and equipment correctly – see pages 11 to 16. Use the ‘VA’ setting on the controller.
Adjusting the timers Look at the selection switches, or menu display/keypad, for the All-Red and Maximum Green timers for each approach. This should make it clear whether to measure the distance between: • the two ‘WAIT HERE’ signs – at sites with more than two approaches, the longest distance to the other ‘WAIT HERE’ signs is used for that approach – or • the ‘WAIT HERE’ sign and the ‘datum’ point.
Datum point Datum point (Note: The Chapter 8 triangular warning signs, guarding on the footway and possible secondary signals have been omitted for clarity.
Adjusting the red timers Measure the distance between ‘WAIT HERE’ signs, or the ‘WAIT HERE’ sign and datum point, (see page 7), and use the table below: Distance (metres) All-Red time (seconds) 0 50 5 100 10 150 15 200 20 250 25 300 30 NOTE: On some controllers the All-Red switch may be marked in metres and the equipment converts to seconds automatically.
Adjusting the Maximum Green settings Measure the distance between ‘WAIT HERE’ signs, or the ‘WAIT HERE’ sign and datum point, (see page 7), and use the table below: Distance (metres) Green time (seconds) 30 75 35 135 40 195 45 300 50 NOTE: On some controllers the Maximum Green switch may be marked in metres, and the equipment converts to seconds automatically. Method of selection and values may differ 0 Set the Maximum Green times to the appropriate settings.
Setting up – general signing Check that full Chapter 8 signing is provided and checked regularly. Log any problems and remedial action taken. Make sure you are familiar with recommendations on the stability of signs and the need for standby ‘STOP’/‘GO’ signs. If possible, avoid placing signs and/or signals on the footway. For additional advice on signing, including that for works on or near footways, see Chapter 8 and the Code of Practice.
Setting up – ‘WAIT HERE’ signs Position the signals where needed. For clear visibility of the signal and reliable detector operation, there must not be any obstructions between the signals and vehicles up to 70 metres away. ‘WAIT HERE’1 signs should be placed before the signal head. If there is a side road controlled by portable signals use the ‘3-WAY CONTROL’2 sign.
Setting up – ‘RAMP’ signs Many portable signals are radio controlled, but some are connected by cable. If the signals are on the near side of the road, cables may have to cross the shuttle lane. Cables crossing a road, should not be placed where vehicles are turning, or accelerating/ decelerating. Where vehicles have to pass over the cable, use a cable crossing protector. These are designed to prevent damage to the cable and to allow vehicles, particularly those with two wheels, to cross safely.
Setting up the MVDs The MVDs work best if they are mounted on signals on the near side of the road. A vehicle approaching the MVD, within the range given on page 5, should be detected. The indicator will be illuminated on the MVD (see page 5). If this does not happen, check the alignment and readjust as necessary. If the indicator still does not illuminate when the next vehicle approaches, call out the service engineer.
Initial set-up of the equipment MCE 0111, TR 0111 TR 2502 1 Point signals away from the road so they cannot be seen by drivers. Align the signals and MVDs – see pages 5, 6, 12 to 14. 2 Connect the signal heads and power supply to the controller. Connect the signal heads and power supply to the controller. 3 Set the controller to ‘MANUAL’. Set the ‘All-Red’ controls – see pages 7 to 9. 4 Set the ‘All-Red’ controls – see pages 7 to 9. Set the ‘Maximum Green’ controls – see pages 7, 8 and 10.
What happens next? MCE 0111, TR 0111 TR 2502 Signals start by showing red. The sequence will start by closing down each approach in sequence through amber, then red. On the last approach, the signals will show green. It is recommended that, when it is safe to do so – working on one approach at a time, turn the signal heads to face oncoming vehicles. Ensure the MVDs are also aligned to face the vehicles. Switch to Vehicle Actuated (VA). The signals to one approach will change – red/amber, green.
Trouble-shooting guide Problem Possible cause Remedy Very long vehicular queues Maximum Green setting needs adjusting See page 10 Faulty detector (MVD) Call service engineer* Too many vehicles Discuss with relevant traffic authority urgently Maximum Green setting needs adjusting See page 10 Faulty detector (MVD) Call service engineer* Low vehicular density No action required Vehicles entering shuttle lane after start of red If frequent, report facts to the police All-Red too short Increas
Trouble-shooting guide (continued) Problem Possible cause Remedy Long gap between last vehicle clearing shuttle lane and start of next green All-Red setting too long Decrease setting Signals do not remain on red in absence of vehicles Signals do not change after one stream has stopped, even though vehicles are waiting * See page 14 for nudge circuit.
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