Source: http://docplayer.net/9752285-This-standard-is-to-be-incorporated-in-the-manual-1-insert-new-content-pages-into-volume-0-2-insert-gd-04-12-into-volume-0-section-2-part-3.html
Timestamp: 2018-03-24 03:20:00
Document Index: 678397379

Matched Legal Cases: ['art 3', 'art 3', 'art 3', 'art 3', 'art 3', 'art 3', 'art 1', 'art 2', 'art 1', 'art 1', 'art 2', 'art 2', 'art. 5', 'art 5']

This Standard is to be incorporated in the Manual. 1. Insert new Content pages into Volume Insert GD 04/12 into Volume 0, Section 2, Part 3. - PDF
This Standard is to be incorporated in the Manual. 1. Insert new Content pages into Volume Insert GD 04/12 into Volume 0, Section 2, Part 3.
Download "This Standard is to be incorporated in the Manual. 1. Insert new Content pages into Volume 0. 2. Insert GD 04/12 into Volume 0, Section 2, Part 3."
1 DESIGN MANUAL FOR ROADS AND BRIDGES volume 0 section 2 INTRODUCTION AND GENERAL REQUIREMENTS GENERAL GUIDANCE Part 3 gd 04/12 STANDARD for Safety Risk Assessment on the STRATegic Road Network SUMMARY This Standard sets out the approach which must be applied in all administrative and technical aspects when designing, operating and constructing for the strategic road network, where safety should be a consideration. It updates, and clarifies, requirements and guidance for addressing safety risks. This includes planning, preparing, designing and constructing highway works, maintenance, demolition and improvements, projects and schemes, and when revising Agency technical standards, specifications and requirements. This Standard sets out the HA requirements for managing safety and as such it does not provide legal advice or guidance. This document only applies to England s Strategic Road Network. instructions for use This Standard is to be incorporated in the Manual. 1. Insert new Content pages into Volume Insert GD 04/12 into Volume 0, Section 2, Part Please archive this sheet as appropriate. Note: A quarterly index with a full set of Volume Contents Pages is available separately from The Stationery Office Ltd.
2 design manual for roads and bridges GD 04/12 Volume 0, Section 2, Part 3 the highways agency Standard for Safety Risk Assessment on the Strategic Road Network Summary: This Standard sets out the approach which must be applied in all administrative and technical aspects when designing, operating and constructing for the strategic road network, where safety should be a consideration. It updates, and clarifies, requirements and guidance for addressing safety risks. This includes planning, preparing, designing and constructing highway works, maintenance, demolition and improvements, projects and schemes, and when revising Agency technical standards, specifications and requirements. This Standard sets out the HA requirements for managing safety and as such it does not provide legal advice or guidance. This document only applies to England s Strategic Road Network.
3 Registration of Amendments REGISTRATION OF AMENDMENTS Amend No Page No Signature & Date of incorporation of amendments Amend No Page No Signature & Date of incorporation of amendments
4 Registration of Amendments Volume 0 Section 2 REGISTRATION OF AMENDMENTS Amend No Page No Signature & Date of incorporation of amendments Amend No Page No Signature & Date of incorporation of amendments
5 DESIGN MANUAL FOR ROADS AND BRIDGES volume 0 section 2 INTRODUCTION AND GENERAL REQUIREMENTS GENERAL GUIDANCE Part 3 gd 04/12 STANDARD for Safety Risk Assessment on the STRATegic Road Network Contents Chapter Part 1 1. Introduction and Use of this Document 2. Defining the People at Risk 3. Duties and Responsibilities 4. General Principles Part 2 5. Principles of Safety Risk Assessment and Control 6. Technical Requirements 7. Roles, Responsibilities and Competence 8. Glossary 9. References 10. Abbreviations and Acronyms Annexes Annex A Annex B Annex C Annex D Generic Safety Risk Analysis Methods Average Road User Safety Risk on GB Roads Hazard Identification and Risk Assessment Tool Cost Benefit Tool
6 Chapter 1 Introduction and Use of this Document Part 1 1. IntroduCTIon and use of this document 1.1 This standard is presented in two parts. Part 1 provides an overview of the Highways Agency s (Agency) safety risk management framework and sets the context within which safety risk management decisions are taken in accordance with this standard. Part 2 takes this information and translates it into a specific safety risk decision making framework for safety risk assessment and control across all of the populations affected by the Strategic Road Network (SRN). Background 1.2 On 28 February 2001 a vehicle came off the M62 motorway at Great Heck, near Selby, ran down the embankment and onto the East Coast Main Line, where it was struck by a passenger train. The train was derailed and then struck by a freight train travelling in the opposite direction. Six passengers and four staff on the trains were killed. The driver of the vehicle was found guilty of causing the deaths of 10 people by dangerous driving. 1.3 The Health and Safety Executive (HSE) investigated the circumstances that led to the incident and their report made it clear that the accident had resulted from a highly unlikely and unpredictable chain of events. However, the Government was concerned about the general issues this crash raised and asked for a wider investigation into the accidental incursion of road vehicles onto the railway. This investigation identified specific actions related to road/rail incursions as well as more general and fundamental issues to do with the methods used by the Agency to assess and record safety risks, and the documentation of the decision processes linked to the management and or treatment of these. 1.4 Since this time the Agency has developed a more transparent approach to safety risk management and has been working towards the embedment of this approach across all of the various areas of the business. Objectives 1.5 Agency projects have traditionally used a prescriptive approach to demonstrating safety, relying on adherence to detailed standards. These standards are based on research, pilot activities and many years of experience, capturing the necessary safety risk mitigation properties. However, this approach is becoming less appropriate for the more complex and innovative systems now being installed on the SRN. The Agency has been successful in improving safety, but this means that future improvements in safety will be much more difficult to realise and thus a more refined approach to safety decision making is required on highway projects going forward. 1.6 This standard updates and clarifies requirements and guidance for addressing safety risks. It introduces the concept of trade off and describes how safety risk tolerance can be used to optimally balance safety risk between affected populations. This approach is not new and the principle of trade off is accepted by the HSE. The trade off principle has been applied: in road over rail situations; in the development of Existing Motorway Minimum Requirements; in Managed Motorway requirements; in the Department for Transport (DfT) Managing the accidental obstruction of the railway by road vehicles report; and in Aiming for Zero projects to improve/benefit worker safety. 1.7 A key requirement of this standard is that appropriate safety risk assessment, evaluation and management is undertaken to inform all activities, projects and decisions. This includes ensuring that the safety risk impacts for different populations (see Chapter 2 Defining the People at Safety Risk ) that the Agency has a responsibility for, along with their safety risk exposure and safety risk tolerance, are taken into account. It also requires that documentation is kept which evidences the decision making process. 1/1
7 Chapter 1 Introduction and Use of this Document Volume 0 Section 2 Scope 1.8 This Standard has been developed in consultation and with the agreement of devolved administrations. It deals with all safety risk management activities in relation to the design of the SRN in England only. It is for other highway authorities and devolved administrations to choose whether to adopt all or part of this standard. 1.9 This Standard does not provide guidance on operational safety risk decision making such as Traffic Officer dynamic risk assessment processes. Operational decisions will need to have regard to the safety risk control measures specified by designers who use this Standard This Standard is not a legal interpretation of the legislation it refers to; as such it does not provide legal advice or guidance. In the event of queries on the applicable law, independent legal advice should be sought. Mandatory Sections 1.11 Sections of this document containing mandatory requirements are identified by highlighted boxes. These requirements are mandatory and no departures from this standard will be accepted. Appropriate safety risk assessment, evaluation and management must be undertaken so that a decision can be made on the basis of what is reasonably required. In circumstances where reliable data is limited or not available the principles of the standard must still be applied; in these instances the professional judgment of a competent person will be required (please see Chapter 6 for more details). The text outside boxes contains advice and explanation, which is commended to users for consideration. Implementation 1.12 This Standard gives the approach which must be applied forthwith by all Agency staff and supply chain, in all administrative and technical aspects when designing operating and constructing the SRN, where safety should be a consideration. This includes planning, preparing, designing and constructing highway works. This includes maintenance, demolition and improvements, projects and schemes, and when revising Agency technical standards, specifications and requirements Application of this standard will ensure that safety risk and investment decisions affecting the SRN are made: Consistently so that similar decisions, made by different people at different times, in different locations result in comparable outputs. Aligned so that full account is taken of Agency targets, objectives, duties, responsibilities and policies. Robustly so that decisions are demonstrated by evidence or expert advice and are auditable. Value so that decisions made represent value for money (VfM). Transparently so it is clear why, and how, a particular decision was taken The processes referenced in this standard should be applied pragmatically and avoid the creation of a burdensome and bureaucratic process. Instead the process should be viewed as an opportunity to simply and effectively record the best judgements of the professionals involved The guidance contained in this standard sets out existing process and best practice that the Agency and its representatives should already be following It should be read in conjunction with the Design Manual for Roads and Bridges (DMRB) and the Agency s Health and Safety Management System contained within the Management Arrangements for Health and Safety (MAHS), where advice and guidance including policy statements for traffic officers, workers, construction workers and other parties can be found. For advice/support and access to MAHS please contact the HA team responsible for Health and Safety. Equality Impact Assessment 1.17 The guidance in this standard has been developed to ensure that all persons affected by the SRN and thereby exposed to safety risk are considered. The safety risk assessment process will itself identify any disadvantaged or vulnerable people and appropriate control measures are mandated. Definitions and Abbreviations 1.18 Terms and references relevant to this standard are dealt with in Chapters 9, 10 and 11 of this document. 1/2
8 Chapter 2 Defining the People at Safety Risk 2. Defining the people at safety risk 2.1 Highway authorities have specific legal duties and responsibilities that are prescribed by various acts and regulations; thus a balanced safety risk assessment methodology that takes account of these must be put in place. 2.2 To illustrate transparent compliance with its legal duties and responsibilities relating to safety risk the Agency has developed the safety risk decisionmaking process described in this Standard. This process must be applied in a manner that enables the Agency to do what is reasonably required to manage, operate and maintain the SRN within the legal duties of the Secretary of State for Transport. 2.3 There are four populations that must be taken into account when considering what is reasonably required to manage their safety risk exposure. These populations are defined on the left hand side of Table 1 below and then these populations have been brigaded for the purposes of this standard into three groups as illustrated on the right hand side of the table. These definitions shall be applied throughout this document and in its interpretation. Population 1 People directly employed by the Agency and who work on the SRN, e.g. Traffic Officers. Population 2 People in a contractural relationship with the Agency, including Agency National Vehicle Recovery Contract operatives, all workers engaged in traffic management activities and incident support services, and any other activities where live traffic is present, (such as persons carrying out survey and inspection work). Population 3 Other parties, including road users, the police and emergency services and non-motorised Users such as equestrians, cyclists and pedestrians, as well as those others not in a contractural relationship with the Agency, such as privately contracted vehicle recovery and vehicle repair providers. Population 4 Third parties includes any person or persons who could be affected by the SRN, but who are neither using it, nor working on it, i.e. living or working adjacent to the SRN, using other (non-agency) transport networks that intersect with the SRN (e.g. local roads, railways) and those who are living or working in properties owned by the Agency. Workers Users Other Parties Table 1 Defining and Brigading Populations 2/1
9 Chapter 3 Duties and Responsibilities 3. Duties and RespoNSIBIlities 3.1 The safety of Workers (see Table 1), is governed by employer responsibilities under Health and Safety legislation. When considering safety risks to these populations (both planned and incident management), the duties of an employer are discharged through compliance with the Management of Health and Safety at Work Regulations (Regulation 3 deals with risk assessments). Where the Agency acts as a designer (either directly or through its supply chain), the requirements to address safety risk assessment for all populations exposed (during construction and maintenance works) is covered by the Construction (Design and Management) Regulations 2007 (particularly Regulation 11). 3.2 The Construction (Design and Management) Regulations 2007 (SI 2007/320), (the CDM Regulations) define structure as including a road. The CDM Regulations define workplace as a workplace within the meaning of regulation 2(1) of the Workplace (Health, Safety and Welfare) Regulations 1992 (SI 1992/3004 as amended) (the 1992 Regulations), other than a construction site. In regulation 2(1) of the 1992 Regulations workplace is defined as any premises or part of premises which are not domestic premises made available as a place of work other than a public road. Thus a designer must consider the use of a public road in the context of its use by Users (Population 3 from Table 1) for normal operation only. 3.4 The principal difference between the populations defined and then brigaded in Table 1 is the level of control that the Agency has over each, e.g. Users have a responsibility for their own safety and are responsible for their actions that may affect the safety of others. Whereas Workers are acting on behalf of and representing the Agency and thus their safety risk exposure is controlled by the Agency s management and operational control processes. 3.5 The activities of Users and/or Other Parties cannot be controlled in the same way as for Workers. Instead it is expected that Users will comply with the law and the Highway Code and that they will take account of all the prevailing conditions (including but not limited to) the weather, road character and condition, traffic level and composition, and any warning signs. The scope of this control is shown in the diagram at Figure The safety of Users and Other Parties (Populations 3 and 4 from Table 1) is generally regulated under statute. There is only one exception to this principle and that is when the use of the road is temporarily constrained by the Agency implementing roadworks. In this instance only, the road is not in a state of normal operation and the Agency s responsibility under health and safety legislation changes because it is undertaking something. In practice this means that during construction and maintenance works the Agency has interfered with the normal operation of the road and this attracts a greater liability, which means that during the period of road work activity the Agency must manage the safety risk exposure of Users differently. 3/1
10 Chapter 3 Duties and Responsibilities Volume 0 Section 2 Workers Users Other Parties Figure 1 Scope of control 3.6 Users on the SRN can be reasonably expected to: balance the safety risks of using the road network against the social and economic benefits of travelling; have a general awareness of the safety risks that they are exposed to (through training, driving instruction and driving tests, road safety campaigns, media reporting of collisions, warning signs on the roads of specific hazards etc.); have control over the safety risks to which they are exposed, of which they are reasonably aware, e.g. heavy rain, congested route; and have a knowledge of their legal obligations whilst using the road and are aware that there is an expectancy that they comply with them. 3/2
11 Chapter 4 General Principles 4. General Principles 4.1 The approach set out in this Standard allows safety risk tolerance, balancing judgments, and benefits versus costs to be examined, while taking account of available budgets and other duties when considering safety measures. This is consistent with HSE guidance for sensible safety risk management, which seeks to ensure that Workers and the public are properly protected, and understand their responsibilities, while providing an overall balance of benefit and safety risk. 4.2 Balancing benefits and safety risks, when considering safety risk control measures, is applicable for all aspects of highway design maintenance and operation to and on a highway. The starting point for development of a design should be to consider the applicability of standards (compliance with standards is one of the simplest practicability tests), any additional controls must be tested using the reasonably required approach. However, where a substandard road feature exists that does not contribute to the safety problem that is the subject of the issue being investigated or addressed; this feature should not automatically be upgraded. When standards can not be fully complied with or where safety risk exposure is a concern, controls will need to be tested for practicability. 4.3 All suitable potential measures to reduce safety hazards encountered by Users must be assessed and those measures that are reasonably required must be implemented. This means that where the cost of a measure identified in the assessment is, in the reasonable opinion of those carrying out the assessment, disproportionate to the benefit derived, then reasonable discretion may be exercised not to implement that measure, but this decision and the evidence used to inform it must be documented. The following rules apply: if the benefit cost ratio (BCR) of the measure being considered is > 2 then it should be considered; if the BCR is < 1 then the presumption is that this is disproportionate and should not be promoted on safety grounds; any other measures with BCR s between 1 and 2 should be considered alongside all the other options and where a greater benefit could reasonably be achieved by allocation of the cost of that measure elsewhere within the scheme or a wider programme of works this should be considered. Benefits will generally be measured against a risk of death, i.e. Value of Preventing a fatality (VPF); depending on the data available other measures such as Fatalities and Weighted Injuries (FWIs), Personal Injury Accidents (PIAs) or incidents could also be used. 4.4 Certain defined people in the Users group (Population 3, Table 1) will undertake a function of their work on the SRN. However, this function is governed by the statutory requirements on their employer s management and operational control processes. 1 Designers must undertake appropriate liaison with stakeholders. 4.5 There is no single methodology for assessing what is disproportionate in terms of safety risk tolerance levels; decisions about safety risk and the controls that achieve compliance have to be carefully considered and specialist technical knowledge and informed judgement is required. 4.6 The Agency can exercise discretion in deciding to provide or omit certain safety control measures. The factor that would be relevant during any form of legal challenge is that A) a decision must be taken and B) the decision must be recorded. This means that a determination to do nothing is a valid decision, if to do nothing is the proper conclusion of the assessment process outlined in this Standard and is documented. However, it is unacceptable for safety risk decisions to be made by default or for a decision not to be recorded. 1 The definition of Road Workers used in the Aiming for Zero vision and strategy document does not apply. 4/1
12 Chapter 4 General Principles Volume 0 Section Other terminology such as Globally at Least Equivalent (GALE) describes a concept that is sometimes used for highway projects. The Agency will instruct when this principle applies and this will generally be where schemes are not primarily safety related. This situation may arise where the overall scheme is being promoted on the basis of reducing congestion. In this type of scenario the safety risk for Users from some composite hazards may be allowed to increase as long as the overall scheme delivers an improved or as an absolute minimum the same global level of safety risk for Users. 4.8 A tool to help decision makers has been provided at Annex C, the tool is not a recipe for assessment and is no replacement for sound judgment and technical expertise. 4/2
13 Chapter 5 Principles of Safety Risk Assessment and Control Part 2 5. Principles of safety risk assessment and control 5.1 The safety risk management flowchart process (Figure 2), applies to all situations described at paragraph 1.7. However, its use depends on the context. Examples of applying this process to different decision types are provided in Chapter 6. Stage 1 Determine the scope Stage 2 Identify the hazards Stage 3 Identify relevant criteria for populations Stage 4 Consider existing risk exposure for each population Stage 5 Risk analysis, assessment and evaluation Stage 6 Risk control decisions Stage 7 Document safety risk decision in a safety risk report Stage 8 Handover of safety risk report to operators Stage 9 Update and refresh the safety risk report when change proposed Stage 10 Monitor and review safety risk report assumptions Figure 2 Safety Risk Management Process 5/1
14 Chapter 5 Principles of Safety Risk Assessment and Control Volume 0 Section All of the actions described in this chapter and in the technical requirement Chapter 6 must be executed by competent persons. The competence and approval process is described in Chapter 7. the safety risk on the population; and the Agency s safety risk tolerance for this population (see Chapter 6). Stage 1 Determine the Scope 5.3 Describe what is included and what if anything is to be excluded from the assessment and record this. The scope may be a geographical area in the case of a road scheme or the boundaries of a decision, e.g. change of process for temporary traffic management at roadworks. In either case the breadth of the assessment or the subject of the decision must be clearly articulated and documented. Stage 2 Identify the Hazards 5.4 Hazard identification must identify all reasonably foreseeable hazards to all populations collectively and individually, and for all modes of operation, using methods appropriate to the level of complexity of the issues. The aim is for a comprehensive understanding of Who, What, Where, When, Why and How populations are affected. A systematic approach, using previous experience where it exists, should be used as a starting point. This may not always be possible, such as when dealing with a new or novel activity or situation, or when there is insufficient relevant and reliable data available. In these instances techniques, such as brainstorming may be required. Other methods, e.g. hazard and operability studies and Failure Mode and Effects Analysis, may also be necessary in specific and technically complex circumstances. Stage 4 Consider Existing Risk Exposure for each Population 5.6 In 2001, the HSE published the report, Reducing Risk, Protecting People, known as R2P2 (to explain their approach to their enforcement role in considering risk tolerability). It explains the concept of trade off, whereby an increase in the safety risk from one hazard can be balanced by a commensurate decrease in the safety risk of another hazard. 5.7 To illustrate the safety risk assessment approach applied by the Agency the updated R2P2 version of the HSE tolerability of risk (ToR) triangle diagram (see Figure 4) has been adapted to fit the requirements and statutory duties relating to highways. The ToR diagram was developed by the HSE on the assumption that people will tolerate safety risks to them if they receive some commensurate benefit in return for being exposed to the risk and that the people responsible for exposing them to the safety risks will take appropriate measures to minimise their exposure. Thus consideration must be given to those persons exposed to, or potentially affected by, a safety risk, see Figure 3. Stage 3 Identify Relevant Criteria for the Populations 5.5 Here the aim is to set out the relevant criteria for the populations affected by the hazards identified in Stage 2. This criterion is then used to examine the need for additional safety risk controls. The criteria to be considered must, as a minimum, include: 5/2
15 Chapter 5 Principles of Safety Risk Assessment and Control Individual The safety risk to a single person is used to represent the risk of all those running the risk, and a specified outcome. The risk measure is the probability of a typical individual member of one of the constituent populations, e.g. Worker, User or Other Party being killed or injured during a year whilst undertaking a particular activity. RISK Collective This is the safety risk, to a group of people or a population, associated with a particular scenario, control measure or hazardous event. Quantified as the average number of fatalities, or fatalities and weighted injuries, per year that would be expected to occur. Figure 3 Individual and Collective Safety Risk Definitions 5.8 For all populations ( Workers, Users and Other Parties ) there are three regions of safety risk that each population could find itself in: Broadly acceptable do nothing, (no additional risk controls or analysis required). Unacceptable do something or stop the activity. Tolerable test for any reasonably required safety risk controls that are not already implemented. 5.9 These are expressed in Figure Moving from the bottom to the top of the triangle in Figure 4 represents increasing safety risk for a particular hazardous activity (measured by the individual safety risk and societal concerns it engenders). The dark zone at the top represents an unacceptable region. There are three regions in the TOR framework that inform the Agency s rules for decision making. Increasing individual risks and societal concern Unacceptable Region Tolerable Region Broadly Acceptable Region Negligible Risk Risk cannot be justified save in extraordinary circumstances Reasonably practicable control measures must be introduced for risk in this region to drive residual risk towards the broadly acceptable region Level of residual risk regarded as insignificant further effort to reduce risk is not likely to be required Figure 4 The HSE s TOR Model or Safety Risk Triangle 5/3
16 Chapter 5 Principles of Safety Risk Assessment and Control Volume 0 Section The Agency applies the HSE tolerability recommendations to Worker and User populations to help us understand the safety risk exposure and tolerance levels for each of them as shown in Figure 5. The safety risk exposure to the Other Parties population is not defined in this Standard and must be dealt with on a case by case basis The HSE advises that an individual safety risk of death of 1:1,000 per annum for Workers who are at work and 1:10,000 per annum for members of the public (Populations 3 and 4) who have a safety risk imposed on them in the wider interest of society, should be used as a guideline for the boundary between the tolerable and the unacceptable regions. This means that for a worker a tolerable safety risk level could be 1:2,500 and for Users this could be 1:15,000. Safety risk located in the tolerable region is judged to be tolerable so long as the determining organisation (the Agency) can demonstrate that there are no further safety risk control and mitigation measures that are reasonably required. Similarly for Users the individual safety risk of death of 1:1,000,000 per annum corresponds to a very low level of safety risk and is used as a guideline for the boundary between the broadly acceptable and tolerable regions An activity/project/scheme that exposes Workers to a risk of greater than 1:1,000 per annum, (e.g. 1:850) is unacceptable. Similarly an activity/project/scheme that exposes users to a risk of 1:9,500 is unacceptable. In these circumstances, either the activities being considered must cease, or additional control and mitigation measures must be implemented to reduce the safety risk to below the boundary between tolerable and unacceptable, and to drive the risk level down as far as is reasonably required. Workers Users Less than 1 in 1,000 Unacceptable Less than 1 in 10,000 Greater than 1 in 1,000 Increasing risk Tolerable Greater than 1 in 10,000 Greater than 1 in 1,000,000 Broadly Acceptable Greater than 1 in 1,000,000 Figure 5 Agency Applying Exposure and Tolerance Levels 5/4
17 Chapter 5 Principles of Safety Risk Assessment and Control Unacceptable HSE risk to Users *Rural A roads 1 in 50,000 *Urban A roads 1 in 100,000 *Motorways 1 in 320,000 Increasing risk Tolerable 1 in 10,000 1 in 1,000,000 Broadly Acceptable Figure 6 Annual Risk of Death to Individual Users by GB Road Type 5.14 The annual risk to road users by road type diagram at Figure 6 has been developed using the same boundaries as those used by the HSE for fatality risk to members of the public. The figures used to calculate this risk exposure and the process is attached at Annex B. It can be seen that in all cases the User annual risk of fatality is firmly in the tolerable region and whilst the annual risk of road user fatality is tolerable on all road types considered here, motorways are the safest roads and are some six times safer than rural A roads The level of safety risk deemed tolerable for a project must take into account a number of criteria: The maximum level of safety risk that is deemed tolerable for the section of road by the decision maker (see Chapter 6 for details). This might consist of a percentage of the overall network or regional safety risk profile or an absolute criterion in terms of Users Killed and Seriously Injured (KSI) and expert advice may be required. Levels of performance for safety risk mitigation systems that are deemed to be a minimum for the duty of care to be met, i.e. the acceptable safety risk exposure for the population. Good practice that is available for mitigating the safety risk (existing standards and/or operational procedures. The cost benefit of different options for safety risk mitigation, as long as they deliver a safety risk level lower than the maximum tolerable safety risk for the populations concerned (as shown in Figure 5) and meet the minimum performance requirements. The overall effects of the actions taken. 5/5
18 Chapter 5 Principles of Safety Risk Assessment and Control Volume 0 Section 2 Stage 5 Safety Risk Analysis, Assessment and Evaluation 5.16 For safety risk analysis the detail must be proportionate to the safety risks being considered. The appropriate safety risk analysis methods may be either qualitative, semi-quantitative or quantitative. A range of safety risk measures are also available for communicating the outputs of any safety risk analysis, including measures of individual and collective safety risk. For details of generic safety risk analysis methods please see Annex A. Outputs from safety risk analyses are compared with tolerability criteria and associated regions of safety risk (see paragraphs ) All potential delivery options for a project must be considered and one recommended that is most likely to result in successful delivery whilst also providing an acceptable level of benefit (and value for money etc.) Populations with safety risks that fall into a broadly acceptable area must be regarded as acceptable and no further risk controls introduced. This means that if a population s collective risk exposure is located in the broadly acceptable region then further risk assessment is not necessary A Safety Risk Assessment Tool (see Annex C) has been provided to assist decision makers in assessing the broad justification in terms of safety risk alone. This tool does not address the other impacts and benefits of the proposal. Where the Risk Assessment Tool is used, a copy of the risk matrix assessment, including the potential hazards identified and the reasoning behind the selection of severity, likelihood and Overall Risk Level should be included within the Safety Risk Report, see Stage 7 of this chapter. Stage 6 Risk Control Decisions 5.19 Risk control is the process of implementing measures that take into account the implications for either A) a single risk or B) a range of different risks and then what is needed to control them across the different populations. Final risk controls must maximise the collective benefit and demonstrate that controls go far enough to manage the safety risks for all populations. Risk control normally involves expenditure and effort, and it is likely that a variety of different risk control options that require different levels of investment and effort will be identified. It is common practice to review the BCR of the different options and select those with the highest BCR. Trade off enables examination of the adverse consequences of options and the comparison of their relative effect; facilitating a balanced decision through a trade off between reducing the target risk (the risk that you are seeking to address) and the increase in other safety risks The process used must take account of safety risk implications for all affected populations. And the method to assess individual safety risk controls shall be: Define the control option; Work out the safety risk implications (benefits and disbenefits) for all affected populations, including consideration of how the control may affect human behaviour, (ie is there evidence to suggest that a population may behave differently because they feel safer or less safe); Consider if the option goes far enough to manage safety risk and if any disbenefits are tolerable (see below); and Revise the option as necessary and repeat until the optimum solution for all populations is found A hierarchy of control measures exists and this is known by the acronym ERIC, which stands for Eliminate, Reduce, Isolate and Control. When considering control measures; the aim should be to work down through the hierarchy; this means that the ideal option will be to eliminate the safety risk you are seeking to control, but this may be unachievable or the costs disproportionate so the decision maker will progress down through the hierarchy applying benefit cost considerations at each level and to each safety risk being addressed. A flowchart for this element of the process is shown at Figure Other Parties are out of scope of this decision-making flowchart. 5/6
19 Chapter 5 Principles of Safety Risk Assessment and Control Understand current problem (Risk Assessment) Identify potential control options (Hierarchy of controls) Understand implications of potential control options for Workers Understand implications of potential control options for Users Understand implications of potential control options for Other Parties Do control options go far enough for this population/are any increases in risk tolerable Do control options go far enough for this population/are any increases in risk tolerable Do control options go far enough for this population/ are any increases in risk tolerable Eliminate options, revise as necessary and repeat Determine preferred option Figure 7 Controls Decision-making Flowchart 5.22 Tests for whether control measures go far enough or whether any disbenefits are tolerable depend on the population and the associated responsibilities of the Agency to manage the safety risk exposure to those populations (Chapter 2, Table 1), and the tolerability criteria described previously (at ). When calculating costs and benefits, technical evidence and judgments must be used to define the expected life/duration of the technical product, project or scheme. The COBA (Cost Benefit Analysis) manual provides guidance on calculating BCR s and the safety risk rules for BCR s are provided at 4.3. The tool at Annex D may also be helpful The expected life/duration of the technical product, project or scheme will vary according to the situation, e.g. for a technology product the life may be 10 years, or for a three week maintenance scheme it would be the duration of the scheme. For simple, low value control measures, this may be qualitative and based on the reasoned judgment of a competent professional. However, as the level of complexity, safety risk or uncertainty increases so must the level of quantification of costs and benefits. 5/7
20 Chapter 5 Principles of Safety Risk Assessment and Control Volume 0 Section For Users, the definition of reasonableness takes account of the following: Costs, time or resources to introduce controls in one area should not impact on the ability to implement other safety measures that deliver more collective benefit or that have a higher BCR. Controls should not have an unreasonable impact on the performance of the network, as measured against criteria other than safety, e.g. journey times or air quality In addition, the costs associated with preventing a fatality should not generally exceed the established value of preventing a fatality figure described in WebTAG unit (Accidents Sub Objective- Table 3: Average value of prevention of road accidents by severity and element of cost) For Workers (Populations 1 and 2) evidence must be presented to demonstrate that the sacrifice (in terms of time, money or effort) of doing more would be disproportionate to the benefits gained from doing it For Workers and Users it can be reasonable for the safety risks associated with individual hazards to increase. However, the residual safety risk level must remain tolerable and the populations subject to the increase in safety risk is gaining some proportionate level of overall benefit from the project or decision as a whole Where individual safety risk controls result in a safety benefit to one population, the outcome for other populations must be that they are not disproportionately adversely affected in safety terms and the residual safety risk to a negatively affected population must always at least remain within tolerable parameters There is no simple methodology for computing what is reasonably required and identifying a proportionate solution. Where there is a need to balance safety risk across different populations, the preferred safety risk control will A maximise safety risk reduction to the population with the highest current level of individual or collective safety risk exposure and B offer the least detriment to the trade off population and C will represent the best overall balance of net present value and benefit cost ratio An extreme trade off example might be to spend 1m to prevent five staff suffering bruised knees is likely to be grossly disproportionate; but to spend 1m to prevent a bridge collapse capable of killing five people is likely to be proportionate At this stage it is appropriate to think about the sensible review period for the safety risk assessment and control measures under consideration The decision about whether or not a control measure is justified will often be based on economic grounds. Thus if a control measure is being disregarded then the impact to the population of any potential increased safety risk stemming from this decision can be estimated in cost terms. This then can be compared with the cost of doing more and thus allow a more informed decision to be reached. A Cost Benefit tool has been provided at Annex D to help decision makers assess whether control measures go far enough. The tool uses an order-of-magnitude technique which provides a simplified methodology to allow designers to consider, on comparable terms, the control measure cost savings against a judgement of the maximum likely change in safety risks. This tool should only be used as a filter and not a single deciding factor since non-accident related impacts (e.g. delays) are not taken into account Safety risk controls are not fixed. It is appropriate to remove safety risk controls that are no longer reasonable/reasonably practicable in circumstances where safety risk profiles, legislation, or approved codes of practice have changed. 5/8
21 Chapter 5 Principles of Safety Risk Assessment and Control Stage 7 Document Safety Risk Decision in a Safety Risk Report Stage 9 Update and Refresh the Safety Risk Report when Change Proposed 5.34 Details of the safety risk assessment must be recorded in a safety risk report, the detail of which will be commensurate with the matter under consideration and will include: the hazards identified and evidence considered; details of the safety risk analysis and safety risk assessment; details of safety risk controls considered and the rationale for why the final choice of safety risk control was considered sufficient; any time limits on the validity of the safety risk assessment/any known or anticipated changes that would require the safety risk assessment to be reviewed; who did the safety risk assessment (and evidence that they were competent, see Chapter 7 for competence requirements) The scale of the safety risk report will be guided by the complexity of the situation, it may be a standalone report for a Type C decision and equally for a Type A decision could be a composite part or section of another project report. Stage 8 Handover of Safety Risk Report to Operators 5.36 The safety risk report is a living document that must be handed on to the next responsible authority, be that a different part of the same organisation or a separate organisation, where this is appropriate, e.g. a built road scheme passing from those responsible for construction to those responsible for operation and management. Thus it must be retained in a suitable format to make sure that it is retrievable for the life of the safety risk controls to which it relates Safety risk assessments contained within a safety risk report are live documents which must be reviewed and updated throughout the life of the project and its subsequent migration to maintenance and operation as part of the SRN: whenever the activity they relate to changes; or when new information or findings from any investigations or problems reported by Workers/Others means that the outcome may change; to reflect any changes in legislation When risk assessments are updated consideration should be given to industry best practice, budgets and other duties, change in situation and ensuring that controls remain reasonably required. Stage 10 Monitor and Review Safety Risk Report Assumptions 5.39 The assumptions that were used to: inform the risk analysis and assessment; inform the risk controls; inform the decisions about whether risks are tolerable; must be updated periodically to ensure that uncertainties are validated and performance reviewed. The monitoring regime shall be contained within the safety risk report. 5/9
22 Chapter 6 Technical Requirements 6. Technical Requirements 6.1 The previous chapters have articulated the general requirements in terms of safety risk analysis, assessment and evaluation, the content of this chapter explains: Who should be the decision maker. What decision makers should take into account, as part of their decision making. An approach that can be used to guide decision making. How much information decision makers should document for an audit trail. 6.2 The minimum requirement is that the outcome of safety risk analysis must be recorded to demonstrate that decisions: Meet Agency requirements. Meet legal requirements. Take account of all relevant factors. Maximise the overall return from available resources. Take account of any implications for others affected by the decision, in both the short and long term. Lead to reasonable, proportionate and defensible set of actions. Produce an appropriate audit trail. 6.3 There are three main inputs into decision making as shown in Figure 8. Appraisal of cost and benefits Decision Making Understand issues Understand risks and uncertainties Figure 8 Decision-making Inputs 6/1
23 Chapter 6 Technical Requirements Volume 0 Section There are four principal steps to making a decision and these are: defining the decision to be made; establishing decision objectives and determining decision boundary; evaluating disproportion and tolerability; and documenting the decision. 6.5 The Agency uses a three-tiered approach (as illustrated in Figure 9) to reflect the safety risks and uncertainties associated with different decision levels related to the complexity of issues. As the level of complexity increases (e.g. the greater the number of scheme elements and/or control measures are involved), the greater the number of trade off /balancing decisions that are required, so the higher the decision-making referral goes. 6.6 Decisions need to be made by the most appropriate person and thus a method to identify the decision boundaries must be applied; To do this the decision must be characterised (i.e. wholly Type A, B or C, or as containing a mix of Type A, B or C characteristics). Table 2: provides an approach that can be used to determine features and thus characterise the decision; the feature descriptions can be amended to suit the decision under consideration. Type C These are decisions which are complex infrequent and/or have major implications for the SRN and, as such, require a detailed and rigorous approach. Type C Decisions Professional Roles Type B These are decisions that could have some significant operational implications. Type A These are relatively routine decisions, are familiar, and without operational implications. The main issue for these types of decision is to ensure they are made consistently with minimum effort and maximum efficiency. Figure 9 Decision-making Pyramid 6/2
24 Chapter 6 Technical Requirements Features Type A Specialist Technical/ Coordinator Roles Type B Professional Safety Advisors Type C Professional Roles What is the size of the decision impact? (geographically and in impact terms; extent of the network, number of Users / Workers ) Local, low density Local, high density or national, low density National, high density What are the cost implications of the decision for the Agency? What is the lifetime of the decision? (how long will the Agency be affected by the decision) What is the level of safety risk or uncertainty associated with the decision? What is the policy or stakeholder interest level? (how sensitive is it?) Low Medium High Rest of the day Months to a few years Decades Low Medium High Low Medium High Note: Stakeholder could be many bodies, e.g. user, worker, another road authority MP etc. Table 2 Characterising Decision Features 6.7 The decision maker should refer to any outputs from previous safety risk analysis, assessment and evaluation work in relation to the matter under consideration, e.g. if a decision or a feature within it has previously been characterised as a Type C this should inform the current decision level ascribed. All evidence considered (both retrospective and new) should be referenced in the safety risk report. 6.8 Having characterised the individual features of the decision (using Table 2) the next step is to determine a resultant overall type for each aspect of the decisionmaking process. The characterisation rules in Table 3 should then be used to identify the appropriate decision maker; this will usually be decided by the project in consultation with the specialist technical advisor. 6/3
25 Chapter 6 Technical Requirements Volume 0 Section 2 Project Feature Classifications Decision Type Comments All Type A Type A Where all decision features are classified as Type A then the entire decision will be of Type A. All Type B Type B Where all decision features are classified as Type B then the entire decision will be of Type B. All Type C Type C Where all decision features are classified as Type C then the entire decision will be of Type C. Three or more Type B, remainder Type A Three or more Type C Equal distribution of classifications across features Type B Type C Type B/C Where three or more decision features are classified as Type B and the remainder are Type A, then the entire decision shall be of Type B. Where three or more decision features are classified as Type C then the entire decision shall be of Type C. Where there is an equal distribution of classification features then the decision shall be governed by the relative importance of the classifications, i.e. a decision may still be a Type B with two Type C features. In this instance then the overall decision type would be Type B but the two features that were identified as Type C would require a greater rigour of analysis assessment and evaluation. Table 3 Characterisation Rules 6.9 When the general approach has been decided between either Type A, B or C, the decision maker must then identify how individual options can be compared to each other. This process is known as establishing decision criteria. The basic process for undertaking this task is summarised in Figure Within the Figure 10 flowchart, value does not necessarily mean monetary, i.e. the results of cost benefits analysis although this will often be the case. Non-monetary types of decision criteria are: Direct data i.e. collision statistics, number of vehicles. Safety risk exposure of workers. Safety risk exposure of users. Reliability/effect upon congestion Whatever criteria, employed, the same combination must be used for all options under consideration so that like for like comparison can be made The preferred option for assessment is Quantitative either financially (i.e. value in terms of ) or nonfinancially (e.g. score out of 100, or absolute value in units other than ). Where it is reasonable to do so, effort should be made to assess decision criteria financially, as this is the easiest way of making direct comparison between the options. The last resort is qualitative assessment, (e.g. high/medium/low or good/ average/poor) which should only be used where the required effort to collect additional robust information is disproportionate to the scale of the decision or it is not practical to quantify the decision criteria (e.g. some dynamic decision making). Financial. 6/4
TREE RISK MANAGEMENT DOCUMENT
TREE RISK MANAGEMENT DOCUMENT INTRODUCTION The Council has a statutory duty of care under the Health and Safety at Work Act 1974 and the Occupiers Liability Act 1999 to ensure that members of the public