Adequate unobstructed width is required to allow two-way traffic to flow safely past the work site. Where such widths cannot be provided, appropriate traffic control must be considered.
Unobstructed widths
The following table shows Standard and Restricted carriageway widths for different types of traffic. The standard widths are designed to maintain access for buses and heavy goods vehicles, and must be provided wherever practicable. Where this is not practicable and where your risk assessment concludes that it is appropriate to do so, restricted lane widths are permissible.
If you are intending to use restricted lane widths that will prevent the passage of HGVs and buses, a suitable diversion route for these vehicles will need to be agreed with the highway authority and bus operator. In these circumstances you must consult your supervisor, manager or other competent person who will advise the relevant highway authority to facilitate co-ordination of the works.
The desirable width for shuttle working with normal traffic (i.e. including buses and HGVs) lies between 3.25 and 3.5 m. This range avoids certain widths that create opportunities for unsafe overtaking of cyclists, and is based on Department for Transport guidance. (Research found that for widths between 2.75 and 3.25 m, most cars could overtake cyclists, but with reduced safety. Similarly, it found that for widths between 3.5 and 3.75 m it was possible for HGVs to overtake cyclists, but again with reduced safety.)
Consideration must be given to this before deciding to use widths other than 3.25–3.50 m for normal traffic in shuttle working. Where shuttle working is restricted to cars and light vehicles only, the upper bound of 3.50 m (which is aimed at preventing HGVs from overtaking cyclists) is not relevant, and a desirable minimum only is given.
| Standard: Normal traffic including buses and HGVs | Restricted: Cars and light vehicles only | |
|---|---|---|
| Two-way working |
6.75 m minimum |
5.5 m minimum |
| Shuttle working |
3.25–3.50 m desirable width range 3.0 m absolute minimum |
3.25 m desirable minimum width 2.5 m absolute minimum |
Warning: Where the minimum width cannot be met, your supervisor, manager or other competent person must consult the highway authority.
Choice of traffic control method
The table below shows various methods of traffic control together with the required conditions for each method. For a given method of traffic control, the relevant conditions in the table must be complied with.
Caution: If the situation is not covered by the methods shown, your supervisor, manager or other competent person should consult the highway authority.
| Method | Max speed limit (mph) | Coned area length | Traffic flow (maximum) | Notes |
|---|---|---|---|---|
| Passive | ||||
| Give and take | 30 | 50 m maximum | 20 vehicles over 3 mins and 20 HGVs per hour | Signing as per figure in section Traffic control by ‘give and take’ |
| Priority | 60 | 80 m maximum | 42 vehicles over 3 minutes | Signing as per figure in section Traffic control by priority signs. Supplementary ‘End’ plates needed if over 50 m |
| Positive | ||||
| Stop/Go boards | 60 | Up to 100 m | 70 vehicles/3 mins | Signing as per figure in section Traffic control by Stop/Go boards. Consult your supervisor, manager or other competent person if greater than 500 m or near a railway level crossing. See also see section Tramways and railways. |
| Up to 200 m | 63 vehicles/3 mins | |||
| Up to 300 m | 53 vehicles/3 mins | |||
| Up to 400 m | 47 vehicles/3 mins | |||
| Up to 500 m | 42 vehicles/3 mins | |||
| Portable traffic signals | 60 | 300 m maximum | No limit | Highway authority permission needed. Signing as per figure in section Traffic control by portable traffic signals. Consult your supervisor, manager or other competent person if at or near a railway level crossing. See also see section Tramways and railways. |
| Speed reduction | 60 | N/A | N/A | See section Traffic control and speed reduction. |
| Convoy working | Temporary limit of 10 mph | N/A | N/A | See section Use of convoy working. |
| Road closure or one-way traffic | 60 | N/A | N/A | See section Traffic control by road closure. |
| ‘Stop – works’ sign | 60 | N/A | N/A | Max period – 2 mins. See section Traffic control for temporary obstruction of the carriageway. |
| ‘Temporary obstruction’ sign | 60 | N/A | N/A | Max period – 15 mins. See section Traffic control for temporary obstruction of the carriageway. |
Setting up traffic control
Before setting up any traffic control, a risk assessment must be undertaken. Where a positive traffic control method is chosen, notification must be given to the relevant highway authority. For the use of portable traffic signals, prior permission is required from the relevant highway authority. However, in the case of immediate works (as defined in the Code of Practice for the Co-ordination of Street Works and Works for Road Purposes and Related Matters), the authority must be informed at the time and an application submitted at the earliest opportunity (but not later than 10 am the next working day).
Warning: When setting up any form of traffic control, the operative must be aware of their own and other road users’ safety.
