Safety fencing and barriers

Design of safety fences and barriers

Safety fences and barriers must comply with Volume 1, Series 400 of The Manual of Contract Documents for Highway Works (MCHW).   The need for barriers/fences should be designed out of residential areas so that layouts create a feeling of place for those not travelling by motor vehicles.

Vehicle Restraint Systems  

Vehicle safety fencing, also referred to as vehicle restraint systems (VRS), are required if certain hazards are present and where vehicle flows are appropriate, to protect highway users.  

VRS are intended to mitigate the risk (as far as practicable) to control, re-direct and contain errant vehicles, to prevent them entering the hazard areas. They should also protect any assets located behind the barrier.  

The Designer needs to consider whether VRS is a requirement during the design stage of highway works, in particular where new assets are being proposed to be added to the Leicestershire network.

Where vehicle restraint systems are required (where flows are appropriate) to address existing issues, then they should accord with:

• Design & Maintenance Guidance for Local Authority Roads
• Provision of Road Restraint Systems on Local Authority Roads for roads with speeds of 40mph or less
• Road Restraint Risk Assessment Process (RRRAP) contained in Design Manual for Road and Bridges CD 377 - Requirement for Road Restraint Systems for roads with speeds of 50mph or more. 

If flows are not sufficient to meet the thresholds in this guidance, then individual risk assessment should be undertaken in conjunction with Road Safety Audit. Care should be taken to avoid the use of vehicle restraint systems to protect road users from the dangers of objects or hazards other than motor vehicles within the highway boundary by first determining whether the objects in question could be relocated to remove the hazard.

Hazards

VRS or other restraint system must be considered or mitigated in any location where there is a risk for a vehicle and its occupants to impact on an existing or proposed hazard.

All proposed works must have an assessment carried out as part of the technical appraisal process, if hazards are present – see list below.

If there is existing VRS, which falls within the proposed extents of the highway works, or hazards are removed or altered by the proposals, then this needs to be addressed as part of the design and technical appraisal process. Any improvement or maintenance works, required due to the proposed works, must be carried out at the developer’s expense.  

General Hazards to consider are (but not restricted to):

• Drainage head walls and ditches > 1m
• Embankments > 1.5m or steeper than 1:3
• Cuttings, bunds > 1m or slope 1:1
• Any form of Structure (including above ground and with restricted head room < 3m) walls, gabions, parapets  
• Environmental trees. Girth > 250mm at maturity, barriers, or screens
• Boundary fences and walls  
• Street furniture including communication poles and cabinets, CCTV apparatus  
• Permanent or expected in any 12-month period water > 600mm deep including river, canal, reservoir, pond, lake or any other that can cause harm to vehicle occupants
• Street lighting columns  
• VMS signs  
• Any sign/ signal post > 89mm diameter  
• Large signs above 2m total hight and 1.5m or less above carriageway level
• Public meeting places, bus stops, schools, hospitals, recreational, retail areas or factories
• Premisses that have chemicals, petroleum, gas tanks or any Hazardous materials in bulk
• Infrastructure, where the impact on the community/ society as a whole is more than the damage caused

VRS process requirements:

All designs, amendments, installation, detailed risk assessments and inspections must be undertaken by a suitable competent person. The Highway Authority reserves the right to request additional details to assess their suitability. The council reserves the right to determine the acceptability of consultants who are proposed to prepare designs for works involving the public highway.  

The designer is responsible for ensuring that the most up to date standards, specifications, codes of practice, legislation and guidance notes are used when designing the highway works.  

In the event there is a delay in the commencement of work, post design and legal agreement, then Leicestershire County Council (LCC) reserves the right to insist the design is reviewed and modified if necessary to comply with any latest publication.

At Approval Stage and AIP (subject to contractor information)

• Assess all locations where there is a risk for a vehicle and its occupants to be impacted by an existing or proposed hazard.
• Local Road Assessment Procedure (LRAP) < 50 , RRRAP > 50, at least one may be required.
• Submission requirements include a standalone VRS drawing, showing system class, set back, working width, length of need (LON), transitions, connections to any legacy systems or parapets (proposed or existing), terminal type and any foundation designs required.
• This should also show the impact severity level (ISL), Vehicle Intrusion zone (VI), Performance class (Z), displacement Zone (D), and compliance with CD377 and MCHW specification for highway works series 400 appendix 4.1.

Prestart meeting (or as soon as a contractor has been appointed)

This MUST be a minimum of (4) weeks before works start on the VRS.

• Manufacturers installation drawings.
• Declaration of Performance (DOP) demonstrating manufacturers / installers compliance on systems and parapets, ISL,VI,Z and D.
• LCC will not accept design responsibility for Transitions, Connections and Terminals we need Acceptance letters from the manufacturers from National Highways for these.
• Manufacturers installation instructions, foundation requirements and testing information / methods.
• Certificates for installers to the National Highways Sector Scheme.

Construction

• Pre-testing of foundations if deemed required.  

At provisional certificate

• As built drawing and details of the constructed system.
• Post testing of systems and information supplied.  
• Certificates of installation for each system

Pedestrian barriers

Where a footpath joins a road, staggered barriers must be provided to:

• Prevent pedestrians running straight out into the road; and 
• Reduce the likelihood of misuse by cyclists.

Details of these barriers can be found in the councils Standard Details.

Pedestrian guardrails

High visibility guardrails must be used where the number of pedestrians makes it necessary to channel them to the appropriate crossing point. Care should be taken so that guardrails do not interrupt visibility. The council will not adopt safety fencing erected on the highway boundary unless it:

• Is provided as a safety feature at the top of any structure retaining the highway; 
• Provides protection against a hazard existing on the adjacent land; or 

Adoption of fencing and barriers

In other circumstances it will be necessary to establish who is responsible for maintaining the fencing in the early stages of discussions.

For works that the council is to adopt, the details of fencing, including brook railings, boundary markers, gates and stiles and pedestrian guardrails can be found in the Standard Details and Series H of Volume 3 of MCHW.