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Guidance documents - Expert

TAG unit 3.4: The Safety Objective

There are two modules within this section:

3.4.1: The Accidents Sub-Objective

3.4.2: The Security Sub-Objective

TAG Unit 3.4.2: The Security Sub-Objective

April 2011

pdf icon Unit 3.4.2(Adobe Acrobat - 75KB)

1. The Security Sub-Objective
   1.1 Introduction
2. Application of TAG to Highway Schemes
   2.2 Methods and Worksheets
   2.3 DMRB Stages 1 and 2/ TAG

3. Social and Distributional Impacts of Security
   3.1 Introduction
   3.2 Which groups of people are particularly vulnerable to the effects of safety?
   3.3 Process to be followed
   3.4 Analysis of Social and Distributional Impacts (Step 4)
   3.5 Appraisal Outputs of Social and Distributional Impacts (Step 5)

4. Further Information
5. References
6. Document Provenance

1. The Security Sub-Objective

1.1 Introduction

1.1.1 Strategies or plans may affect the level of security for road users, public transport passengers and freight (all modes). The aim of this sub-objective is to reflect both changes in security and the likely numbers of users affected. Depending on the nature of the strategy, an assessment of changes in security can be entered into the AST reflecting impacts on the security of road users, public transport passengers or freight (all modes), or on combinations of these. A potential for overlap with the 'interchange' sub-objective exists. To avoid this, some indicators which reflect both security and interchange quality have been included only in the interchange assessment.

1.1.2 For public transport passengers, the DETR Mobility Unit has produced best practice guidelines for railway stations and public transport operators (Mobility Unit, 1998). This raises a number of key security issues and gives guidance on design and management practices. These are broad ranging and only a key sub-set has been included in the security indicator list within Table 1.

Table 1: Security Indicators for Public Transport Passengers

Security Indicator Poor Moderate High
Site perimeters, entrances and exits Unmarked or poorly marked site perimeters, exits etc. Use of solid walls or similar. Attention to boundary and exit marking, but otherwise unfavourable use of materials. Clearly marked site perimeters/exits. Use of open fencing rather than solid walls.
Formal surveillance No CCTV system in place. Design discourages staff surveillance and isolates passengers. CCTV system in place, but number, location of system not optimal. Poor design which discourages staff surveillance. Effective CCTV system in place. Design to encourage staff surveillance and group passengers.
Informal surveillance Poor use of materials(fencing etc) and design. Poor visibility from site surrounds. Very isolated from retailers or other human activity. Unfavourable use of materials (fencing etc) but reasonable proximity of retailers or other activity. Positive use of materials(fencing etc) and design to encourage open visibility from site surrounds. Encouragement or proximity of retailers or other activity.
Landscaping Landscaping features(design, plants etc) inhibits visibility and encourages intruders. Evidence of some positive use of landscaping features(design, plants etc), but more measures needed to contribute to visibility and deter intruders. Positive use of landscaping features(design, plants etc) to contribute to visibility and deter intruders.
Lighting and visibility Poor design including recesses, pillars, obstructions etc which hinder camera/monitor view. Poor or no lighting in passenger areas at night when facility open. No or poor lighting on any signing, information or help points. Design includes some recesses but not problematical to camera/monitor view. Lighting in passenger areas at some, but not all times when facility open. Lighting not to daylight standard. Attention to lighting on signing, information and help points. Good design to avoid recesses and facilitate camera/monitor view. Lighting to daylight standard in passenger areas when facility open. Attention to lighting on signing, information and help points.
Emergency call No or very poor provision of emergency phones, help points and public telephones. Little provision or information on emergency help procedures. Basic provision of emergency phones, help points and public telephones. Improvements to these and on emergency help procedures needed. Good provision of emergency phones, help points, public telephones and information on emergency help procedure.

1.1.3 There are no formal guidelines for road users. However, the guidelines set out in Table 1 can be readily interpreted for application to road users. Points to note when considering these security indicators in relation to road users are:

  • road users are more vulnerable to crime in circumstances where they are required to stop their vehicles or travel at slow speeds, such as at the approaches to signals or in congested conditions;
  • road users are more vulnerable to crime at locations where they are required to leave their vehicles, such as at service stations, car parks and so on; and
  • the importance of each indicator is likely to vary according to the location and nature of the road, thus, for example, emergency call facilities are likely to be more important than surveillance when considering a rural road.

1.1.4 For freight, security at the terminal or interchange should be assessed using the 'interchange' sub-objective. As for road users, the indicators shown in Table 1 may be interpreted for application to other aspects of freight movement.

1.1.5 Worksheet 1 should be used to carry out an appraisal of the impact of a project on security. Where more than one mode is affected by a project, separate versions of Worksheet 1 should be used for each mode. The first step in the appraisal is to assess the level on each security indicator both prior to and following the implementation of the project. The levels should be assessed according to Table 1 and recorded in Worksheet 1. Worksheet 1 also requires an assessment of the relative importance of each of the security indicators. As indicated above, this will vary by mode and may also vary by location.

1.1.6 An overall assessment of the security impact can then be made by considering the changes in the level of the security indicators, the relative importance of the indicators, and the approximate numbers of users affected, given the following guidelines.

1.1.7 The overall assessment is likely to be neutral if, given the relative importance of each indicator, improvements on some security indicators are considered to be generally balanced by deterioration on other security indicators.

1.1.8 For the following categories, if the shift is generally to the right of the Table 1 the assessment would be beneficial and the assessment would be adverse for a shift to the left.

1.1.9 The overall assessment is likely to be slight where changes on most of the more important indicators is a shift between adjacent columns or the total number of travellers/freight users affected is low (less than 500 travellers per day, or 10 freight users per day, say).

1.1.10 The overall assessment is likely to be large where changes on most of the more important indicators is a shift of more than one column or the total number of travellers/freight users affected is high (greater than 10000 travellers or 100 freight users, say).

1.1.11 The overall assessment is likely to be moderate in all other cases.

1.1.12 In addition to the overall security assessment it is recommended that further quantitative details may be entered in the AST including estimated number of users affected. A further qualitative description is recommended, particularly where the nature of the strategy lies outside the type of indicators proposed here. The qualitative description should reflect the potential benefits or disbenefits of a particular strategy relative to the do-minimum scenario and reflect specific security measures or issues where appropriate.

1.1.13 When assessing strategies, the approach may need to be adapted to function with lower and/or more aggregated levels of information. Thus, for example, where project level assessment might consider each site (service station, bus station and so on) separately, strategic assessment might take all sites of a given type together. Another adaptation might be to base the assessment of the level on each security indicator less on detailed knowledge of the security characteristics of the network, and more on expert judgement.

2. Application of TAG to Highway Schemes

2.1.1 This section provides advice on the links between TAG's treatment of the security sub-objective and the advice given in Volume 11 of the Design Manual for Roads and Bridges (DMRB), which deals with the environmental assessment of highway projects. An explanation of the correspondence between the advice set out in TAG and DMRB is given in Applying the multi-modal new approach to appraisal to highway schemes (TAG Unit 2.6).

2.2 Methods and Worksheets

2.2.1 This category did not previously appear in DMRB.

2.2.2 In the roads context, Security includes the perception or risk of personal injury, damage to or theft of vehicles, and theft of property from individuals or vehicles. There are three locations in which security issues may arise when using roads:

  • on the road itself (e.g. being attacked whilst broken down);
  • in service areas, car parks and so on (e.g. vehicle damage while parked at a service station, being attacked while walking to parked car); and,
  • at signals or junctions (e.g. smash and grab incident while queuing at lights).

2.2.3 Some of the main security indicators, the location(s) they refer to, and different levels of performance are indicated in Table 2 (this is a roads oriented adaptation of Table 1).

Table 2: Security Indicators for Roads

Security Indicator Relevant Locations Poor Moderate High
Formal surveillance Service areas, car parks, some roads No CCTV system. Presence of security staff not apparent CCTV system in place but number, location not optimal. Passive system monitoring by staff Effective CCTV system in place, used for active real-time monitoring
Informal surveillance Service areas, car parks Poor design that hinders observation of public areas by staff Neutral characteristics Design features facilitate staff monitoring
Landscaping Service areas, laybys Landscaping features (slopes, trees etc.) inhibit visibility. For laybys, not visible from road Generally good, but with a small number of features that conceal areas Clear sight lines exist to all areas. No concealed areas. For laybys, clearly visible from a distance
Lighting and visibility Service areas, car parks, laybys and possibly trunk & slip roads Large areas obscured from view or unlit Few areas where lighting is dim or absent Well lit, no areas obscured from view
Emergency call facilities Car parks, laybys Difficult to locate, damaged or non-functional Reasonable level of service Well located, easy to identify & in full working order
Pedestrian and cyclist facilities Bridges and under-passes Obscured from view, poorly lit Reasonable features Well lit, designed for visibility

2.2.4 Although Table 2 is intended to assist in the assessment of security indicators, the AST entry relates to the overall change in security features. As an example, if security enhancements are important and result in a change from 'poor' to 'high', the overall assessment score that enters the AST may be 'Large Beneficial'.

Worksheet 1: Assessment of Security Sub-objective

Security Indicator Relative importance
Without strategy
With strategy
Site perimeters, entrances and exits

Formal surveillance

Informal surveillance


Lighting and visibility

Emergency call

Approximate numbers of users affected ________________________________________

Overall assessment of impact on Security sub-objective
(slight/moderate/large positive/negative or neutral) _______________________________

Reference Source(s): _______________________________________________________

Qualitative comments: ______________________________________________________

3. Social and Distributional Impacts of Security

3.1 Introduction

3.1.1 This section provides additional advice on the technical processes to be considered in the assessment of the potential social and distributional impacts of changes in security resulting from transport interventions. The analyst should, in addition, make reference to Detailed Guidance on Social and Distributional Impacts of Transport Interventions (TAG Unit 3.17) in undertaking this work.

3.2 Which groups of people are particularly vulnerable to the effects of safety?

3.2.1 Literature demonstrates that there are several groups with particular concerns about their personal security (refer to references in Section 5). Women, younger people (teenagers), older people, people with disabilities and Black and Minority Ethnic (BME) communities tend to perceive risk more acutely when using public transport and, furthermore, public transport users tend to be from lower income groups. This can lead to greater anxiety and potential suppression of travel, which could reduce the effective accessibility of the transport system.

3.2.2 There are, therefore, potential social impacts (in personal security terms) from making changes to the transport system, and these should consider the specific concerns of women, young people, older people, people with disabilities and BME communities. Distributional impacts could otherwise be considered, in terms of impacts on households in different income bands.

3.3 Process to be followed

3.3.1 The approach to the assessment of the social and distributional impacts should follow the process described in TAG Unit 3.17. In terms of security, this follows the following steps:

  • Step 0 - an initial screening process to identify any likely positive impacts or negative impacts that cannot be eliminated through design or mitigation;
  • Step 1 - identification of the area impacted by changes in security;
  • Step 2 - analysis of the demographic profile of residents living within the area impacted by changes in security;
  • Step 3 - a screening process, to determine if it is appropriate to undertake further analysis of the changes in security and the approach to be taken;
  • Step 4 - the core security analysis; and
  • Step 5 - the collation and presentation of the outputs from the security analysis.

3.3.2 The process to be followed for Steps 0-3 is described in TAG Unit 3.17.

3.3.3 In the event of security impacts being identified from the screening process (Step 3), the sections below should be used to guide the technical analyses required for Steps 4 and 5 of this social and distributional impact appraisal process.

3.3.4 The following section refers to the full appraisal process. TAG Unit 3.17 also notes that alternative approaches can be taken when impacts are neither significant nor concentrated. These are intended to be more proportionate and are more qualitative than the full appraisal. TAG Unit 3.17 sets out the principles that can be applied.

3.3.5 For both the full appraisal and the more proportionate qualitative appraisal, the promoter should develop a specification for the appraisal and agree this with the Department (or equivalent) before proceeding with the appraisal.

3.4 Analysis of Social and Distributional Impacts (Step 4)

3.4.1 The analyst should appraise the collective security impacts of the transport intervention, in accordance with the guidance described in Sections 1 and 2 of this TAG Unit.

3.4.2 The security impacts (both actual and perceived) of the transport intervention on a number of potential vulnerable groups should be assessed. Careful consideration should be given to the potential issues faced by:

  • Older people;
  • Younger people;
  • Women;
  • People with disabilities; and
  • BME communities.

3.4.3 Consideration should be given to the typical journeys made by the various potential vulnerable groups and their likely time of travel. For instance older people are unlikely to be travelling for work purposes and hence not travelling during peak commuting times when natural surveillance will be at its highest. Younger people are more likely to travel for social reasons in the evening when perceptions of security are heightened by incidence of anti-social behaviour and potential concerns of users about isolation and travelling alone.

3.4.4 These impacts should consider all types and aspects of the journeys, including:

  • The walk or cycle to and from the public transport stop or for the entire journey;
  • The experience of waiting at the public transport stop; and
  • The experience of the in-vehicle journey by public transport.

3.4.5 The analyst should also consider the following:

  • The vehicles to be used (bus, light rail or train) and the security aspects such as on-board and external CCTV, visual awareness and lines of sight, staffing levels and resources, driver communications, and public alarms;
  • Existing and new waiting stops to be used for a public transport corridor;
  • Existing and new interchange or station facilities; and
  • Subways, footbridges, cycle paths or footpaths providing access to the public transport facility.

3.4.6 The analyst should draw on research that has been carried out to date in considering the travel and security issues that are faced by these different groups of people (evidence can be found in the report quoted in Section 5 of this TAG Unit). In the case of an intervention that has relatively modest impacts on security, this existing research will be adequate in considering these issues.

3.4.7 Worksheet 2 should be used to undertake analysis of the social and distributional impacts of security. Table 3 below provides a worked example, using the worksheet, for the assessment of the impacts on potential vulnerable groups resulting from changes to security features in the transport network. It provides the scores for a hypothetical improvement to a public transport interchange facility, which is used by around 8,000 users per day.

Table 3: Worked example of an Assessment of Personal Security SDIs

3.4.8 This worked example is based on the existing approach used for the assessment of security, but has been enhanced to describe the impacts on specific potential vulnerable groups.

3.4.9 Column [A] in the worksheet is based on the change in the individual security indicator resulting from the intervention. A score of zero signifies no change (for example, a moderate score in both 'without intervention' and 'with intervention' cases). A score of 1 signifies a slight improvement (for example, from poor to moderate, or moderate to high). A score of 2 signifies a larger improvement (for example, from poor in the 'without intervention' to high in the 'with intervention' case).

3.4.10 The worksheet applies a scoring system, taking into account the weightings applied by different user groups, to calculate an overall assessment of the impact of the public transport improvement on the population at large and on individual potential vulnerable groups. It can be seen that the score is highest for women (at 17) and lowest for young people (at 10).

3.4.11 The overall assessment of security impacts is likely to be large when the improvement to one of the more important indicators is substantial (ie from poor to high), and when the number of users is greater than 10,000. The worksheet shows that there are two important indicators with substantial improvements: lighting and visibility and staffing, which are shaded in the table.

3.4.12 There are a total of 8,000 users per day, which gives an overall assessment of moderate beneficial. In the case of the each potential vulnerable group, it is necessary to make a qualitative assessment, based on the estimated numbers of users and security score for each group. In the case of older people, there are only 500 users per day, which triggers a slight beneficial score, whilst the other groups receive a moderate beneficial score.

3.4.13 It can be seen that the completion of Worksheet 2 requires judgements, based on the existing evidence base, of the importance of different elements of security to different potential vulnerable groups using the transport system. In the case of relatively simple interventions, in which there are relatively minor changes to infrastructure, it is adequate to use this desktop-based approach.

3.4.14 In the case of a more complex intervention (in which the potential security impacts are not clear), or an intervention that has an explicit objective to improve security, the analyst should consider the need to proceed to the step below.

The Role of a Site Visit/Audit

3.4.15 It should be noted that a site visit/audit is encouraged as part of the process of analysing local severance issues in the area, and this could provide an opportunity to identify security issues in relation to infrastructure when travelling in the local area, including to and from public transport stops.

3.4.16 The process of undertaking a site visit/audit is described in The Severance Sub-Objective (TAG Unit 3.6.2), and the analysts responsible for the security and severance appraisals should therefore liaise, to ensure that key issues are addressed and findings from the site visit/audit are taken into account in the security analysis.

Primary Research

3.4.17 Primary research should only be considered in the case of complex interventions that will have significant impacts on security for a large number of people within potentially vulnerable groups, or for transport interventions which have an explicit objective to reduce security.

3.4.18 This type of research should be specifically targeted at the potential vulnerable groups identified in the previous steps, to gain information and understanding on how the intervention is likely to affect them. However this should not preclude the analyst from considering other groups that could be affected in the local area. Options for primary research include discussion groups (qualitative research) or surveys of these groups (quantitative research). The analyst should use judgement in determining the most appropriate approach to be used, which should be appropriate to the scale of the intervention and the number of potentially vulnerable groups identified.

3.4.19 This research should identify specific security concerns, and the extent to which people will change their journeys in response to these concerns. The research should also be used to identify the relative importance of each personal security indicator to each of the potential vulnerable groups.

3.4.20 The primary research should consider the following issues during the discussion groups, in terms of the current issues, potential improvements with the intervention, and the importance of the issue to the different groups of people:

  • Personal security in the walk from home to the public transport stop;
  • Issues in relation to site perimeters, entrances and exits (at railway stations or other segregated public transport);
  • Levels of formal surveillance - including CCTV;
  • Levels of informal surveillance, for example being near to busy roads or shops, or being overlooked by houses;
  • Landscaping - for example overgrown bushes obscuring sight lines;
  • Lighting and visibility - are there any dark spots or are there blind spots where people could hide, and is there a role for good lighting in helping to improve facial recognition?;
  • Provision of emergency call facilities - which might also be of assistance in the event of missing a train, as well as reporting problems of anti-social behaviour;
  • Staffing of facility - to what extent is the presence of a member of staff an important factor in helping people to feel more safe?;
  • Security during the public transport journey itself: for example, does the presence of an on-board conductor help reassure people?; and
  • The walk from the alighting stop to the final destination - for example, walking back home from the train station after a late evening out in the city centre.

Report to Project Manager and Design Team

3.4.21 The data from the desktop analyses (and primary research, if appropriate) should be used to inform the scoring in the appraisal process. It should also be used to identify the scope to improve the design to better tackle particular security concerns amongst the potential vulnerable groups under consideration.

3.4.22 The analyst may identify security concerns and interrelated issues that fall outside the initial design remit of the transport intervention. This may require further investigation and involvement from other public sector partners, for example, issues relating to street lighting, which should be discussed with the local highway authority.

3.5 Appraisal Outputs of Social and Distributional Impacts (Step 5)

3.5.8 The main outputs produced as a result of the personal security appraisal process will be a structured worksheet, in a similar format to Worksheet 2. This will also highlight any potential issues that can be tackled during the design stage.

3.5.9 The scores for each of the groups under consideration should then be reported in the matrix of social and distributional impacts, described in Step 5 of Detailed Guidance on Social and Distributional Impacts of Transport Interventions (TAG Unit 3.17).

Worksheet 2 - Assessment of Social and Distributional Impacts of Security

4. Further Information

The following documents provide information that follows on directly from the key topics covered in this TAG Unit.

For information on: See: TAG Unit Number:
Severance and issues affecting journeys on foot and the role of the site visit The Severance Sub-Objective Unit 3.6.2
The background and overall approach to the Social and Distributional Impacts of transport interventions Detailed Guidance on Social and Distributional Impacts of Transport Interventions Unit 3.17

5. References

Department of the Environment, Transport and the Regions (DETR), Design Manual for Roads and Bridges: Volume 13 Economic Assessment of Road Schemes, The Stationery Office: London.

Hopkin, J M and Simpson H F (1995) Valuation of Road Accidents, TRL Report163, Transport Research Laboratory, Crowthorne.

DETR Mobility Unit (1998b), Secure Stations Scheme, DETR: London.

Atkins and MVA (forthcoming) Assessing Social and Distributional Impacts in Transport Scheme Appraisal.

6. Document Provenance

This Transport Analysis Guidance (TAG) Unit is based on Chapter 5 Section 3 of Guidance on the Methodology for Multi-Modal Studies Volume 2 (DETR, 2001).

This document has been updated in January 2010 to reflect the guidance on Social and Distributional Impacts.

Technical queries and comments on this TAG Unit should be referred to:

Transport Appraisal and Strategic Modelling (TASM) Division
Department for Transport
Zone 2/25 Great Minster House
33 Horseferry Road
London SW1P 4DR

Email: tasm@dft.gsi.gov.uk
Tel: 020 7944 6176
Fax: 020 7944 2198

Updated: April 2011