| Type of closure | Maximum allowable traffic flow | |
|---|---|---|
| Veh/hr | Veh/3 mins | |
| Dual two-lane carriageway | ||
| Lane 1 | 1200 | 60 |
| Lane 2 | 1200 | 60 |
| Dual three-lane carriageway | ||
| Lane 1 | 2400 | 120 |
| Lane 3 | 2700 | 135 |
| Lane 1 + 2 | 1200 | 60 |
| Lane 2 + 3 | 1200 | 60 |
| Dual four-lane carriageway | ||
| Lane 1 | 3600 | 180 |
| Lane 4 | 3900 | 195 |
| Lane 1 + 2 | 2400 | 120 |
| Lane 3 + 4 | 2700 | 135 |
NOTES:
- Figures are based on an HGV content of 15-20%. Where the HGV content varies from this, the above figures may need to be adjusted; see paragraph O10.4.4.
- When working past slip roads the maximum flow on the slip road should not exceed 500 vehicles per hour (25 veh/3 minutes) without assistance with traffic control.
- When two lanes are closed, central reservation matrix signals, Variable Message Signs (VMS) (Section O10.5) and the light arrow sign (paragraph O10.7.5) should be used.
- For work on dual four-lane carriageways, three advance sign vehicles are the absolute minimum required. The MLC technique should not be used on such carriageways unless matrix and/or VMS signals are employed, preferably in conjunction with a light arrow sign; see paragraph O10.7.5.
MATRIX SIGNALS
O10.5.1 Where roads are suitably equipped, the use of matrix signals and VMS is recommended for MLCs which encroach on live running lanes. This is often facilitated through agreement between the contractor and the local police for a particular site. However, it would be preferable for the appropriate Overseeing Organisation to establish area-wide agreements with the police, and where applicable, regional control centres and traffic officers.
O10.5.2 These arrangements will need to include advance notice requirements. They should also include an agreed method for police or regional control centre to contact the MLC supervisor while the closure is in operation, because in the event of an accident or incident, the signals/signs may have to be altered.
O10.5.3 In establishing these arrangements, reference will need to be made to the codes of practice, "The Joint ACPO and HA Policy and Procedures for the use of Variable Message Signs (VMS) by the Police and Regional Control Centres "(Highways Agency/ACPO, 2005) and “The Joint ACPO and HA Policy and Procedures for the Police use of Matrix Signals" (Highways Agency/ACPO, 2002). The codes of practice referred to are those related to roads in England. For details of the appropriate rules that apply in Scotland, Wales and Northern Ireland refer to the appropriate regional government.
O10.5.4 If the proposed operations involve the use of matrix/VMS signs, pass through areas where the carriageway or junction layout is not straightforward, or will require other police or traffic officer assistance, then contact should be made with the relevant police force or regional control centre at an early stage.
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