the practice of road safety audits - wit press...road safety audits can be undertaken throughout the...

The practice of road safety audits

H.C. ChinDepartment of Civil Engineering, National Universip of SingaporejSingapore.

Abstract

In recent years, road safety audits have been introduced in a number of cmmtriesas a proactive means of improving road safety and rect@ing potential safetydeficiencies on the road. In contrast to the usual accident investigation procedurethat is undertaken tier crashes are observed, road safety audits seek to ident@safety problems prior to crash occurrence and even before the road project iscompleted. This paper presents a brief history of the development in the practiceof safety audits and outlines the common procedure undertaken in such audits.The benefits and liability concerns associated with such audits are also discussed.The paper also describes a methodology of risk assessment not found in the mostmanuals on road safety audits.

1 Introduction

For many years, safety researchers and pmctitioners have made concerted effortsto reduce crash occurrences on the roads. While there seems to be generalimprovements in safety standards in our vehicles and on the roads [1], theincrease in motorization continues to inflict an unacceptable fatality and injurytoll on road users worldwide.

Traditional safety programs tend to be reactive, i.e., safety improvement schemesare designed based on and following observed crashes. Such an approach isunlikely to result in substantial decrease in crash reduction occurrences and roadcasualties. In recent years, there have been calls by various authorities to achievequantum reduction in fatality rates [2]. This has led many agencies to exploremore proactive strategies to deal with the root causes of safety deficiencies in theroad system.

© 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved.Web: www.witpress.com Email [email protected] from: Urban Transport VIII, LJ Sucharov and CA Brebbia (Editors).ISBN 1-85312-905-4

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In the 1970s and 1980s, there were various attempts in North America andEurope to examine traffic conflicts, which were considered to precede crashoccurrences. Though more proactive than many accident investigation programs,traffic conflict studies [3] still require road projects to be completed beforeactions can be taken.

It seems sensible that a more proactive road safety enhancement strategy is onethat examines the crash risks or potential of road projects even before suchprojects are completed. This principle underlies the practice of road safety audits.

AustRoads [4] defines a road safety audit as a Normal examination of anexisting or future road or tmffic project, or any project which interacts with roadusers, in which an independe@ qualified examiner reports on the project’saccident potential and safety performance@. Such audits were first introduced inthe 1980s in the United Kingdom based on the safety audit concepts originallydeveloped for railroad networks during the Victorian Period. It was done as partof a Quality Assurance Scheme in a nuinber of County Councils to facilitate asystematic check of highway projects prepared by the County Councils [5]. Thispractice was formalised in the United Kingdom in 1990 with the publication ofThe Institution of Highways and Transportation on Guidelines for the SafetyAudit of Highways [6]. The guidelines were subsequently revised [7] when theDepartment of Transport in United Kingdom made it mandatory for all majornational trunk roads and motorways to be audited.

At the same time, a similar safety audit process was initiated in New Zealandwhen the newly formed Transit New Zealand was given the responsibility toconduct post-construction safety reviews of road projects [8]. Initially, pilotreviews were conducted for state highway projects, but by 1993 a set of policiesand procedures [9] was already developed and implemented for all types of roads

In Australi& road safety audits were fust introduced in the State of New SouthWaies in 1990 [10]. The practice was quickly foIlowed by other states and in1994, the Australian Road Authority, AustRoads [4] has published its ownguidelines on auditing roads in Australia.

In the last decade, road tiety audits have been adopted in similar fashion inother countries in Europe [11-12], North America [13-14], Africa [15] and Asia[16-17].

2 Objectives and benefits of road safety audits

Road safety audits were introduced as an attempt to implement quality assurancein organkitions involved in planning desigm construction and operation of roadprojects. Hence they are some form of quality contxol checks undertaken atspecitic points in time so as to ensure quality is maintained throughout the life


[ ‘1’banTramport in the 21s[ Century 7(j5

cycle of a road project. Specifically, road safety audits are aimed at achieving thefollowing objectives:1. To identif$ potential safety problems faced by all road users and others whomay be atTectedby the road project;2. To ensure adequate measures are considered to eliminate or minimise thepotential safety problems.

Most road designs tend to favour the drivers rather than non-drivers. Forexample, the criteria for establishing cumatures in horizontal and vertical roadprofiles are solely based on the performance of drivers in maintaining adequatesight distances and speeds. Consequently, other road users may be inadvertentlyforgotten in the design process. A failure to provide adequate and appropriatefacilities for vulnerable road users can often lead to unsafe conditions for theseroad users who may resort to taking unsafe actions. By considering all road users,particularly the vulnerable ones in the examinatiorz road safety audits seek tocover whatever lapses in safety considerations in the design process.

There are identilable benefits in conducting road safety audits. Evidently, thenecessity of safety audits makes thow who are responsible for road developmentand maintenance become more aware of the safety requirements in their projectsand will indirectly help to promote a better road safety culture among roadproviders and operators. Potentially, safety audits should reduce the likelihood ofcrash occurrences as well as severity of crashes on the roads. Such reductionscan mean significant economic benefits to the road users and operators as well asto society as a whole. When hazards are identified early and measures toeliminate them are taken promptly, there will be a reduced possibility of havingto undertake expensive remedial works on the completed road systemsubsequently. Furthermore, by noting design deficiencies that are highlighted ina safety audit designers camwork to incorporate safety features into their fhturedesigns, bringing about improved designs and facilitating a more efficient way ofupdating design standards and procedures. The extensive documentation requiredin safety audits can also lead to better appreciation of the principles of roadsafety engineering among highway engineers and operators.

While there appears to be Potential benefits in road safety audits, there are fewquantitative assessments to confirm these benefits, despite the numerous safetyaudits that have been undertaken to date. It has been argued [18] that since roadsafety audits are unlikely to cost more than accident blackspot programs whichhave been shown to result in significant econotic benefits, the benefit to costmtio of safety audits should be high. Based on some early work done in NewZealand [9], the potential benefh to cost ratio of 20:1 seems to be attainable.

3 Types of road safety audits

As a formal process of assessing the crash potential and safety performance of aroad project, the safety audit requires an independent and qualified team to be the


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assessor. Such an examination is not considered to be a design check as it dealsonly with safety issues. However, as a complete safety check, the concerns of allroad users, including motorcyclists, pedestrians and cyclists, must be taken intoaccount.

Road safety audits can be undertaken throughout the entire life cycle of a roadproject from conception to operation. Various types of road safety audits havebeen defied in road safety audit manuals and these are conducted at thedMerent stages of the life cycle in the road development, as follows:1. Feasibility stage. In this case the review looks at the route options, layoutoptions and treatment options. The audit allows an assessment of the relativesafety performance of scheme options and identifies the specific safety needs ofthe various potential users based on the adjacent land use. It may also highlightthe need to reprogram other nearby road or @fic projects to ~elyaccommodate changes in trtdlic.2. Preliminaq Design Stage. At this stage, the issues such as intersection orinterchange layout and the alignment details are addressed along withconsiderations on the design standard to be chosen.3. Detailed design stage. Once the design details are available, the geometricdesi~ traffic signing scheme, line marking plans and landscaping plans areexamined in relation to the operational safeiy of the road.4. Post-Construction Stage. A critical safety audit is undertaken just before theroad is opened to the public; hence the audit done at this stage is also regarded asone at the Pre-Opening Stage. Site inspections are made under various conditions(e.g. day and night setting) and the safety impact is examined for all road userswho will likely use the road. This audit ensures that hazards identified earlierhave been rectified and are in place before trailic is allowed on the road. Otherdeficiencies not apparent on the drawings are easily identified at this stage.5. fiis~ing Roads. A safety audit can also be conducted on roads that are inoperation. Safety aspects of the road network may have changed signit3cantlysince the road was first built. For example, the development of adjacent land andnew roadside features such as new signage or commuter facilities may have asafety implication on the operation of the road.6. Temporary Road Works. In a major road-upgrading program, there can bemany elements in the road scheme that may be hazardous to the road users. Asafety audit during this stage can signifkantly improve operational safety andensure that the usually tight road construction schedule does not compromise onsafety.

Audits may not be conducted at every stage of the road project. Indeed, there aredit7erences in what are required in the various safety audit guidelines. TheAuStRoads guide [4] recommends only the first five categories. In New Zealan&the audit of existing roads is applicable only at a network level and while theaudit of temporary road works may not appear in the audit guide [9], its practicehas been encouraged [19]. The British manual [7] has only the fust fourcategories because it considers the traditional accident investigation programs to


1‘rbrmTronsport in the 21.7t(-<ntq 767

be equivalent to audits of existing roads, Nonetheless, there is a subtle difference– as a proactive approacl+ an audit of existing roads need not be called onlywhen crashes have occurred This may explain why many County Councils inUK have carried out audits on existing roads [20]. In Singapore, audits are notearned out at the feasibility stage because there is usually little time gap betweenthe f~ibility stage and the preliminary design stage.

4 The audit process

There are specfic steps in the audit process that are spelt out in the variousguides. AustRoads [4] details 7 steps horn the point of selecting an audit team totaking follow-up actions after the audit, These steps are discussed below.

Selection of the audit teamThe first logical step in the audit process is selecting the audit team. This mayseem straightfoIwar& but concerns raised at this step are those centred on thequalifications and composition of the audit team.

The need for a qualified team stems from the requirement that the road safetyaudit has to be a formal exercise. Consequently, members in the audit team are tohrwe both the relevant educational qualifications and experience, typically, intraffic engineering, road safety engineering or accident investigation andprevention. In some instances an undemanding of the local issues is seen to bean advantage although it may be argued that someone with a diHerent cultumlbackground may provide a more objective assessment on safety. For the audit tobe carried out without bias, it is also necessary that the audit team should have nodirect involvement in the design or execution of the road project. Thisindependence is necessary to ensure that the project will be evaluated with “afresh pair of eyes”. Furthermore, it is considered desirable for auditors toconsider only safety issues and not be biased by design considerations known tothe design team.

The composition of the audit team is also an important consideration thoughthere appears to be no consensus on its requirements. Ideally, the team shouldcomprise several individuals with diverse backgrounds and experience, who willcomplement each other in evaluating the safety performance. Based on auditexercises undertaken in training classes, it has been found that in general, auditsare better conducted and more safety issues are raised by teams whose membersare drawn from professionals with different training and experience in roaddesi~ construction, maintenance, traflic operation or @aHic management.However, in practice, it maybe diflicult and costly to muster a large and variedteam. Consequently, some authorities have allowed one-member audit teams toaudit their smaller road projects.


Provision of Background informationBefore the audit team takes on the job, the road designer or project manager willneed to prepare the necessary background materials and supporting documentsfor the audit team.

The information to be gathered depends on the type of audit to be undertaken.The background to the road project may include information related to theintended function of the road section to be audited as well as information on theadjacent streets and intersections. The existing or projected vehicular flows andpedestrian flows and the kinds of vulnerable road users expected are also madeknown. Where applicable, the accident history of the site may also be needed.

In all cases, drawings of the road project such as the traffic plans, layout plans,horizontal and vertical profiles as well as typical road sections are essential. Theaudit team also needs other documents such as design specifkations andconstraints as well as reports of previous audits, at this stage. In audits oftemporary road works, operational safety procedures for workers as well asemergency plans are also reviewed.

Commencement meetingThe formal meeting between the project team and the audit team marks thecommencement of the audit proper. In this meeting, the project team briefs theaudit team on the road project to be audited.

The idea of having one=s work to be audited is often uncomfortable and thecommencement meeting can generate some tense moments of hostility. It isknown that road designers have found it difficult to accept that their design skillsare questioned by those who have little or no experience in road design [21],Setting the right atmosphere in the commencement meeting and treatingdesigners with respect for their professional work can gain invaluable supportfrom the designers, which can lead to higher quality in the reviews [22].Emphasizing the complementary roles in promoting safety can also bring aboutgreater mutual benefits in professional developments.

Safety Ana@sisThe purpose in a safety analysis is to ident@ the crash potential of the roadproject. To do this, the audit team needs to examine the drawings as weli as carryout site inspections under various conditions. All audits, irrespective of the stageof the road project, should include a site visit so that ground conditions can beproperly understood [23].

Whether on the drawing or at the site, the auditors have to undertake a systematicappraisal of the risk potential. Few road safety audit guidelines provide arigorous methodology on how this is to be done. One of the more structuredapproaches is that adopted by Singapore Land Transport Authority (LTA), whichfollowed the concept based on military risk assessment [24].


L“rban Ttwnsport in the 21st Centzyv 769

Applied to road safety audits, risk assessment is the decision making process thatseeks to evaluate and control the likelihood of occurrence and the severity of acrash, The process involves ident.i@ing the potentird hazards, evaluating theextent of the risks involved and establishing fbrther controls and precautionsneeded to mitigate the risks.

The steps in the risk assessment methodology areas follows:1. Risk identification: Specitic hazards are identified and described. A roadhazard is defined as any unsafe condition on the roadway that can generate anincident that will inllict potential injury or harm to any road user. Risk is ameasure of the potential for such a dangerous incident being realised. Hence, theconcept of risk is a combination of two elements: the likelihood of a crash andthe severity of the crash In reporting the hazard it is important to indicate boththe location and nature of the hazar~ i.e., how the unsafe condition may result inan undesirable unsde outcome. The description should include not only the typeof vehicles and road users that will be involved but also the manner the crashwill likely occur, Since different road users are involv~ there may be severalhazards at a single location.

2. Impact assessment: For each of the hazard identifie~ its severity is nextdetermined according to some ordinal scale. The level of crash severity isinfluenced by the mture of the crash and the vulnerability of the road usersinvolved. Table 1 shows the four categories of severity adopted by LTA [25]together with the corresponding definitions and examples. Since severity may bereduced by possible evasive actions of the road users and the kind of safetyprotective devices used, the choice of the severity level can be subjective anddependent on the judgement of auditors.

Table 1: Crash Severity

Categoq Definition ExamplesHigh Multiple fatalities andlor serious Head+n crash

injuries High-speedcrashMedium Single fatality or severe injory Pedestrian or cycliststruckby car

with possibleother minor injuries Side-swipecrashLuw Minor injuries or property LOW speed crash

damageonly CyclistfallNegligible Propertydamage only Car reverses into post

Car crashes into guardrail

3. Probability estimation: Following impact assessment the expected frequencyof occurrence in the hazardous event is determined by estimating the likelihoodof occurrence. This estimate also requires good professional judgement from theauditor. Four categories of accident frequency are proposed in the LTAguidelines [25], ranging from frequent to improbable. These are defined andillustrated in Table 2.


4. Risk Rating: The category of risk for each hazard is evaluated by mapping theimpact and probability values against the risk matrix as shown in Table 3. Therisk rating establishes whether the risk of any potential hazard is acceptable ornot.

Table 3: Risk RatingRisk Category Accident Severi& Category

Negligible Low’ Medium HighAccident Frequent B A A A

Frequency Occasional c B A A

Category Remote D c B AImprobable D D c B

A Intolerable – Risk shatl be reduced by whatever means possibleB: Undesirable – Risk sbsll be accepted onty if cost of risk reduction is disproportional to gainC: Tolerable – Risk shatl be accepted if cost of ixtsprovcment is highD: Acceptable – Risk is minimal

5. Risk management: Once the risk rating is known, the appropriate courses ofaction needed to manage or mitigate the risk can next be worked out. Where therisk mting is exceptionally hig& it is imperative that such risks should bereduced by whatever means possible. On the other hand, the risk level may be solow that nothing needs to be done to reduce it further. In most cases, risk ratingsfall into the region where the risk needs to be managed. In such cases, thedecision to mitigate the risk is based on a comparison between the expectedbenefit in a risk reduction measure and the likely cost incurred. In general, risksshould be reduced as much as practically possible and economically feasible.

To assist the review team in the tasks of risk assessment checklists or promptsare often used. A @ of the customised checklists is usually included in the mostguidelines on road safety audits. These typically show the sort of issues andproblems that can potentially arise at the relevant stages of the road project. Themain advantage of using such checklists is that this formalised checkingprocedure can help ensure that potential problems will not be overlooked.Checklists may also be helpful for the designers to review their work before it issubjected to a formal audit by the audit team.

Safety reportAs a formal process, the safety audit will require a report to be produced. Thereport details the findings related to road safety deficiencies identifkd and makes


1‘rban ~“rampmt in the 21s[ Centzvy 771

the necessary recommendations for mitigating these identified hazards. Thereport usually contains a background description of the road project with a mapor location plan. As plans and designs are modified constantly, it is important toknow which sets of drawings have been audited, ‘I%M the report will usuallyinclude a list of the plans, drawings and documents and their versions that havebeen examined.

The main part of the report is devoted to hazard description. For each hazardidentified in the audi~ the location of the ha.zad and how it may develop ispresented together with the nature of the potential crash and the result of the riskassessment, The risk rating and the recommended remedial measures toeliminate the risk are also included. To facilitate ease of reference, these areusually organised and presented in a tabular form. This is supplemented by a setof appropriate photographs showing the hazards and the sumounding roadconditions. The list of the hazards and their ratings, together with therecommendations are summamd in a form at the end of the report. Thissummarised list is intended for the project team to document their response to theaudit tidings.

Completion meetingFollowing the submission of the safety audit repo~ it is usual for the audit teamto orally present the findings to the project team. This is done at the final meeting.With the help of visual aids and photogmphs to describe the hazards and roadconditions, this presentation of audit findings can sometimes be more effectivethan the written report in bringing across the safety concerns observed by theaudit team. While the project team needs to examine all the recommendations inorder to make an appropriate response, it is not normal for the project team torespond to any of the recommendations during the meeting itself.

Response reportThe indirectconsequence of having a formal safety audit is that there needs to bea response from the project designer or builder to the recommendations raised inthe audit report. In responding to each of the safety deficiencies identified, thedesigner or project manager may choose to accept or reject the existence of sucha potential hazard. Where there is concurrence on the existence of the h- theproject team may choose to agree or disagree on the risk rating. Finally, theproject team may decide to adopt the recommended remedial actions or suggestan alternative or even to reject the recommendation and take no action.Whenever the design team or project team differ from the assessment of the auditteam, it is normal to document the reasons for the differing opinions.

The safety audit submission and the response report are usually presented to thenext level of management overseeing the project. Lnsmaller projects, the reportsmay end up with the immediate superiors of the designers or builders but inlarger projects, it is not uncommon for a high-level safety review committee toexamine the safety and response reports.


One of the main stumbling blocks to having more extensive use of road safetyaudits is the concern over professional liability. The manner in which liabilityimplications are viewed may depend on the cultural setting of the country andpxactice of governance. In Austral@ anyone alleging professional negligencemust prove that the party charged with the duty of care has failed to act withreasonable diligence. Thus in calling for road safety audits, the authorities orroad providers can show themselves to have acted with due diligence and hencebecome less subjected to litigation. In New Zealan& where the nationalinsurance program does not permit lawsuit for personal injury, the liability issuein road safety audit does not arise.

Safety auditors have always expressed concerns over liabilities should there bemishaps arising from safe~ deficiencies that have not been identified in the audit.Some have argued that the role of auditors is ditlerent from that of accidentinvestigators. In a safety audit, the intention is to identify safety problems so thatsafety deficiencies can be filly considered [18]. On the other han~ accidentinvestigation seeks to apportion blame or award compensation. Hence, followingthis argument, the liability of reviewers should not be an issue.

There are still serious debates over the legal implications arising from theconduct of road safety audits, particularly in the United States where governmentdecisions are subject to intense legal scrutiny. One concern is whether a team,agency or authority would become liable to those crashes that occur followingthe rejection of a safety audit recommendation. Such fears may indeeddiscourage agencies from carrying out safety audits. However, as safety auditsdeal with potential hazmls while accident analysis deal with manifested hazards,then assuming that potential hazards cannot be treated as evidence for lack ofsafety, it has been argued [18] that agencies are no more liable in conductingsafety audits than in executing programs to identi@ hazardous locations

6 Conclusion

For the road safety process to be successful there should be commitment to theaudit process at all levels, from the management of an organisation to the variousworking levels of stti and contractors. Often the audit process is perceived to bea challenge to the competence and professional judgement of the designer orroad builder. This can inhibit the sharing of vital information. On the other han~the audit process may also be treated as an approval of the design. In this case,designers and contractors have known to adopt a more careless attitude, knowingthat their failings will be picked up. For the process to work well. all thestakeholders must view the audit process as an important avenue to promote road


safety and to prevent the occurrence of crashes. It seems that much work is stillrequired to encourage the various parties to agree on this common goal.

In the last decade, there has been significant progress in the development oftiety audit pmctices around the world. Yet there remain numerous challengesahead. As in many safety initiatives, there are as many sceptics as advocates.There are those who remain unconvinced that there is enough evidence of realsafety benefits. It has also not been proven that the objective of creating a saferroad environment and inculcating a safety culture among road prof~sionalsthrough safety audits has been achieved. Furthermore, there needs to be moreresearch work to improve the assessment methodology. The manner of assessingrisk as described in this paper, though more rigorous than what is reported inexisting road safety audit manuals, is still far horn perfect.

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