Contents
Annex 5
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1. Introduction
This Annex considers the management of Safety Fences, Boundary Fences and Environmental Barriers. These shall all be inspected for integrity as part of the general highway safety inspection programme for carriageway, footways and cycleways.
Road Restraint Systems (RRS) are safety fences that require a more comprehensive inspection strategy as their purpose is to prevent the number and severity of injuries in the event that a vehicle leaves the road and would otherwise encounter a hazardous feature. Self-evidently in protecting a vehicle’s occupants, a RRS also protects against damage to any highway asset located behind the system.
UKRLG in conjunction with the DfT have provided Design and Maintenance Guidance for use of RRS on local authority roads. Design and Maintenance Guidance (ciht.org.uk) This Guidance Document provides the outline of an appraisal process to help authorities decide when a RRS is justified. This appraisal takes account of the many diverse influencing factors including risk assessment, alternative solutions, system feasibility, cost benefit analysis and the availability of funding. Road Restraint Systems are sub-divided into Vehicle Restraint Systems (VRS’s) and Pedestrian Restraint Systems (PRS’s).
Pedestrian guard-railing is a safety fence aimed at improving pedestrian safety by trying to prevent pedestrians from crossing the road at an inappropriate place or from straying into the road inadvertently. Guard-railing can also be used to offer some protection to pedestrians at locations where the swept path of large vehicles, such as buses and heavy goods vehicles, takes the vehicles close to the footway, sometimes overhanging it. The DfT has provided guidance in Local Transport Note 2/09 Pedestrian Guard-railing
2. Inventory
To proactively maintain the asset into the future, we will continue to build a comprehensive inventory and good understanding of condition, including the associated risks that come with failure. This will enable us to undertake assessment and to prioritise programmes of preventative maintenance, whilst monitoring and reviewing performance.
Ideally the asset register would hold information on all individual assets and include type, length, material type, age, speed limit, last inspection. Although we have some of this data for some fences and barriers there are many omissions and much of the information has not recently been verified. It is recognised that a large number of Boundary Fences are the maintenance responsibility of private landowners.
As the current maintenance strategy for Boundary Fences, Environmental Barriers and Pedestrian Guard-railing is limited to a reactive response to safety inspection concerns, improving this inventory data will remain a low priority for the service.
However, the maintenance strategy for Road Restraint Systems includes a risk-based service inspection and annual planned renewal and replacement. Consequently, inventory data on location, type and condition of these assets is much more critical.
Inventory plans have been recorded showing the system and terminal types and location of all Vehicle Restraint Systems on the Major Road Network (including overbridges), all road / rail incursion sites, all Trunk and Motorway overbridges and remaining maintenance category 3’s to 6’s. This data is also available within the highway asset inventory register.
3. Performance
3.1 Boundary Fences, Environmental Barriers and Pedestrian Guardrails
Routine serviceability inspections are not undertaken on these assets, so there is limited information on current condition. However, the safety inspections process will identify any defects that will render a fence or barrier dangerous. In such circumstances, the defect will be repaired, or made safe whilst a repair is arranged. Where defects result from accident damage, the Council will aim to recover costs from responsible third parties.
3.2 Road Restraint Systems
Damage and defects are captured through safety inspection or following road crashes. Each year this results in approximately 40 repairs countywide with 75% affecting systems on the Major Road Network.
A risk-based inspection and repair regime has been developed and over the last 8 years, successive annual programmes of work have been targeted to identify and improve the performance of these systems. A specialist contractor has been engaged to inspect all main roads (maintenance category 3-6). Repairs are prioritised following a risk-based approach with all high-speed roads and road/rail incursion renewals completed as a priority.
4. Maintenance Strategy
How the asset is managed in each stage of the life cycle.
4.1 Boundary Fences, Environmental Barriers and Pedestrian Guardrails
Creation of a new asset
These assets are created in association with highway improvement schemes or new developments. As with the creation of other highway assets it is important that consideration is given not just to their necessity but also the quality, durability and routine maintenance needs of the materials selected.
Routine maintenance
As there is currently no serviceability inspection regime, routine maintenance is rarely undertaken. Where treatment is identified by road users for aesthetic reasons, e.g. painting railings, communities are encouraged to use self-help initiatives to address this.
Renewal or replacement
Fences and barriers are renewed and replaced as necessary when identified by safety inspection of by crash knockdowns. Where possible, costs associated with vehicle damage are recovered from insurers. Consideration should be given to the necessity of replacement and renewal, how the asset has failed. Material selection is influenced by whole life cost and carbon usage.
Decommissioning of the asset
It would be unusual for fences or barriers to be removed unless they required replacement. However, as technical standards and the highway environment are subject to change, consideration should be given to bulk removal using the Minor Scheme Assessment (MSSA) process where replacement of a damaged section of barrier is deemed unnecessary.
4.2 Road Restraint Systems
Creation of a new asset
A United Kingdom Roads Liaison Group (UKRLG) Guidance Document has been prepared for use by highway authorities and their designers considering the introduction or replacement of RRSs on local roads Design and Maintenance Guidance (ciht.org.uk). It describes a process to assist highway authority decision making with regards to investing in a RRS at a particular site. It includes the necessary supporting information to assist this process and takes account of risk, risk assessment methods, costs, benefits as well as further advice on performance specification and outline design.
The Guidance recognises that any RRS has an inherent element of risk and that this risk has to be balanced by the benefit of mitigating the severity of any accident at an affordable cost.
This Guidance Document applies to:
- New roads (and the adoption of roads),
- Road improvements e.g. widening, junction improvements,
- Where a new hazard is introduced, or an existing roadside feature is altered e.g. the addition of roadside features,
- Where the upgrade or replacement of a parapet is being considered,
- Maintenance schemes where a significant length of RRS is being replaced, and
- When the safety performance of a particular site has been questioned and risk reduction options are being assessed.
| Speed Limit > 50mph | This Guidance | RRRAP CD 377 |
| Speed Limit <50mph | This Guidance | This Guidance |
| < 5000 Average August Daily Traffic | > 5000 Average August Daily Traffic |
Fig. 5.1: Applicable method for determining when an RRS is required.
Where traffic volumes exceed 5000 vehicle per day and speed limits exceed 50mph, the ‘Road Restraint Risk Assessment Process (RRRAP)’ which forms part of CD 377, Design Manual for Roads and Bridges will be used to enable the designer to determine, at each specific site, the need for a vehicle restraint system and its performance requirements.
Routine maintenance
The design and selection of VRS solutions may mean that periodic maintenance should be undertaken, for example, re-tensioning corrugated beams at a given frequency. Specialist inspections enable the development of a routine maintenance regime. Currently such an approach is undertaken on the Major Road Network every 2 years. Further consideration should be given to extending a risk-based inspection process to identify routine maintenance for RRS systems on other road categories.
Renewal or replacement
A risk-based approach has been undertaken to systematically inspect and repair RRS over the last 8 years. Details are shown in the following table:
| Priority No. | Criteria and location |
| 1 | 1A – High risk sites A380/A361/A39 |
| 1B – Principal road timber post | |
| 1C – Review of road/rail high risk sites | |
| 1D – Timber post systems over motorway/trunk road network over bridges | |
| 2 | Inspect all A road rail over bridge and adjacent rail systems and repair where necessary.
|
| 3 | Inspect all remaining road rail over bridge and adjacent rail systems and repair where necessary. |
| 4 | Inspect all dual carriageway central reservation barriers and repair where necessary.
|
| 5 | Inspect all m/c 3 high risk sites based on accident severity, commercial traffic data, speed limit and section type and repair where necessary. |
| 6 | Inspect all m/c 4 high risk sites based on accident severity, commercial traffic data, speed limit and section type and repair where necessary. |
| 7 | Inspect all remaining trunk road over bridge sites and repair where necessary. |
| 8 | Inspect all m/c 5 high risk sites based on accident severity, commercial traffic data, speed limit and section type and repair where necessary. |
| 9 | Inspect all m/c 6 high risk sites based on accident severity, commercial traffic data, speed limit and section type and repair where necessary. |
Fig. 5.2: Table showing risk-based priority for RRS renewal or replacement.
This is a long-term inspection cycle that spans numerous years. Each year, a planned works programme is generated from this and other data sources such as road collisions and safety inspections.
An updated risk-based serviceability inspection is being developed for inclusion within the forthcoming maintenance contract. A scoring system will be used to assess condition and provide indicative repair timeframes.
In addition, the Council has implemented a joint process with Network Rail to demonstrate that they have ranked sites where roads cross or run alongside railways according to their relative risk and that they have considered how to manage that risk.
The Highway Authority also consider a bridge vulnerability scoring matrix in prioritising planned Road Restraint System upgrades.
Road Restraint Systems are repaired as necessary when identified by safety inspection or by crash knockdowns. Where possible, costs associated with vehicle damage are recovered.
Scheme design considers the accident risk, whole life cost, carbon usage in production, and future replacement strategy. For instance, the inclusion of sockets has proved highly effective in the rapid replacement of knockdowns, minimising temporary traffic costs and reducing traffic delays on busier sections of the main road network.
Decommissioning of the asset
Removal of Road restraint Systems can occur from time to time. This could result from reduction or removal of risk. For example, the introduction of passive road signage or a reduction in speed limit or by other Highway Engineering options at our disposal. Before proposing the installation of a replacement RRS the designer should consider either removing the hazard or reducing the hazard to an acceptable level
All timber posts (which are no longer used) are disposed of to a licensed tip (as a result of possible contaminants i.e. creosol), all steel materials such as posts, beams and fixtures are recycled.
Maintenance Service Standards
Maintenance Service Standards were developed which define the service of provision for each asset type based on three levels: Safety, Safety and Serviceability or Safety, Serviceability and Sustainability. These are defined in terms of what a road user could expect to see. This is useful in understanding the maintenance standard in the context of what is affordable.
As pressures on budgets continue and become more restrictive, the ability of the Council to provide a service above that of safety is going to be severely impacted.
The tables below show the maintenance standards for Fences and Barriers on each road category.
| Carriageway Hierarchy | Service Level | Footway Hierarchy | Service Level | |
| 3 | 1 | |||
| 4 | 2 | |||
| 5 | 3 | |||
| 6 | 4 | |||
| 7-10 | ||||
| 11+ |
Key
| Maintenance Standard 1 | Provision of Safety, Serviceability and Sustainability |
| Maintenance Standard 2 | Provision of Safety and intermediate level of Serviceability |
| Maintenance Standard 3 | Provision of Safety and minimal level of Serviceability |
| Maintenance Standard 4 | Provision of Safety only |
Fig. 5.3: Maintenance Standards for Fences and Barriers for each Road Category
| Fences & barriers | Provision of safety related issues only | Provision of safety and minimal level of serviceability | Provision of safety and intermediate level of serviceability | Provision of safety, serviceability, and sustainability issues |
| What a road user would see | Fencing, Barriers, Pedestrian Guardrail and Vehicle Restraint Systems safe and looking untidy. | Fencing, Barriers and Pedestrian Guardrail safe and Vehicle Restraint Systems safe and in fair order. | Fencing, Barriers and Pedestrian Guardrail safe and Vehicle Restraint Systems safe and in good order. | All fences, barriers pedestrian guardrails and Vehicle Restraint Systems in good order. |
| Maintenance standards and activities | Undertake safety inspections and react to defects that represent an immediate or imminent hazard. | Undertake safety inspections and react to defects that represent an immediate or imminent hazard.
Limited routine maintenance based on hierarchy. | Undertake safety inspections and react to defects that represent an immediate or imminent hazard.
Risk-based service and specialist inspection prioritising condition led scheduled routine maintenance based on hierarchy. | Undertake safety inspections and react to defects that represent an immediate or imminent hazard.
Service & specialist inspections of Vehicle Restraint Systems and development of a risk-based programme for renewal/removal based on fit for purpose and condition analysis. |
| Impact | No condition assessment to assess whether fit for purpose leading to increased possibility of failure and potential claims. | Limited programme of renewal/removal based on risk rating
Some improvement to asset reducing the likelihood of failure and reducing claim potential | Limited programme of renewal/removal based on risk rating.
General improvement to asset reducing the likelihood of failure and reducing claim potential. | Improvement to asset reducing the likelihood of failure and minimising claim potential. |
Fig. 5.4: Maintenance Standards for Fences and Barriers
5. Levels of Service and Investment Strategy
5.1 Levels of service
Levels of Service demonstrate the relationship between the Council’s corporate objectives, including the Strategic Plan for 2021 – 2025, and the performance of highway structures assets in terms of stakeholder requirements. The Levels of Service represent the fundamental service aimed at helping to deliver a road network which is as safe, reliable and as fit for purpose as possible within the current funding and resource constraints. Table 5.5 is an extract from the Strategy and shows the Levels of Service measures for Safety Fencing along with an indication of how they relate to the Council’s Levels of Service Statements.
| Asset | Service | Measure | Responding to the climate emergency
| Be ambitious for children and young people
| Support sustainable economic recovery
| Tackle poverty and inequality
| Improve health and wellbeing
| Help communities to be safe, connected and resilient
|
| Safety Fencing | Vehicle restraint systems, Guardrail, Fences
| Assess safety fences when they are knocked down or damaged and repair, replace or remove as required. | √ | √ |
Fig. 5.5: Levels of Service for Safety Fencing
5.2 Investment strategy
There is currently no investment strategy in place for the renewal of Boundary Fences, Environmental Barriers and Pedestrian Guardrails due to the limited financial resource available.
The risk-based approach to replacement and renewal of Vehicle Restraint Systems is funded annually through the capital programme. The allocation is currently based on historical needs.
6. Programme Development
6.1 Identifying Schemes for an Initial Works Programme
Damaged and defective Boundary Fences, Environmental barriers and Pedestrian Guardrails are identified through safety inspection or by reported RTC’s. These are forwarded to the Council’s delivery team to progress with the necessary works which are carried out through their approved Fencing Contractors and/or Term Maintenance Contractor.
Damaged and defective Road Restraint Systems are also identified through safety inspection or by reported RTC’s. In addition, condition surveys have been completed on all main roads (maintenance Category 3-6) This process considers the appropriateness of the current safety system. These locations receive a specialist serviceability inspection and where appropriate, programmes of maintenance, repair or replacement are designed by a specialist.
6.2 Prioritising the Works Programme
The programme of works follows a risk-based process prioritising high speed, high traffic roads and road /rail hazards.
7. Risks
Issues which may prevent asset management objectives being achieved:
- Financial risk – safety or specialist inspections may identify a demand for repair or renewal over and above the financial provision available,
- Availability of materials – programme delay could occur due to material shortages, particularly associated with steel production or importation, and
- Design lead-in time – Establishing ownership or responsibility and identifying an appropriate technical solution for each scheme may result in delay of implementation.
In all the above circumstances, works prioritisation and measures such as temporary traffic management and temporary speed limits may need to be implemented.
It is important to regularly review opportunity for removal of barriers that are no longer required, particularly with the financial cost and carbon production associated with continued maintenance.
8. Improvement Actions
Alongside the Highway Infrastructure Asset Management Plan, this Annex is a live document. It will be subject to continuous improvement and ongoing development with input from Council Officers and Stakeholder feedback. Areas for improvement are identified within the Annex which are summarised as Improvement Actions in this section. These Actions are aligned with Strategic Goals and are assessed as part of a wider cross-asset prioritisation process that prioritises their implementation taking account of the framework of funding and resource availability.
The actions that have been identified as being required to ensure the Fences and Barriers asset management objectives are achieved are:
- Re-tensioning programme – an identified routine programme of RRS should be identified, risk-rated and funding provision secured,
- An RRS Capital Investment strategy should be developed by need and priority,
- Review of existing RRS risk-based approach. Consider use of scoring matrix to determine inspection priority and frequency and planned work programme. Consider Benchmarking and comparison with neighbouring authorities,
- Consideration of risk-rated temporary measures where repair works cannot be addressed due to funding, and
- RRS Inventory needs to be consistently monitored/updated to support routine maintenance, specialist inspection regime and investment strategy.
Version Control
| Version | Date | Summary of Changes |
| 1.0 | 12 April 2023 |