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SAFETY ASSESSMENT FOR TWO LANE RURALLOCAL ROADS – EU-IASP PROJECT

Salvatore Cafiso,Associate Professor, University of Catania

Grazia La Cava,Ph.D., P.Eng., University of Catania

Alfonso Montella Assistant Professor, University of Naples

1 INTRODUCTIONRoad safety evaluations on two-lane rural roads withlow/medium traffic flows can raise concerns both due tothe general deficiency of reliable data on road accidentsand to the circumstance that few crash data due to lowtraffic, not always can give enough information onaccidents distribution and causes.Based on these considerations, the project“Identification of Hazard Locations and Ranking ofMeasures to Improve Safety on Local Rural Roads”(Italian acronym IASP), funded by the EuropeanCommission (DG TREN) and the Province of Catania(Italy), aims to define a methodological approachpurposely designed for the safety evaluation of two-lanelocal rural highways. The proposed model usesprocedures referring both to the geometric designconsistency of road alignment and to the SafetyInspection process. Nowadays, Road SafetyInspections (RSI) are recognized as an effective tool foridentifying safety deficiencies of road infrastructures.They represent a low cost process for the evaluation ofthe network safety performance. Its applicability in rurallocal roads, where accident data generally do not giveenough information for the safety analysis, makes theprocedure very attractive. As part of the project, safetyinspections of 100 km of two lane rural roads have beencarried out. The IASP safety inspection proceduresreflect the scope of the project and give somequantitative safety evaluation, to the best extentcompatible with a methodology mainly based onsubjective evaluations.A part of the project was aimed at defining a RSIoperative procedure able to improve the effectivenessand reliability of the methodology. For this purpose, theresearch was focused, after a brief research on RSIstate of practice, on the review framework, on thereviewers roles and, with special emphasis, on themethodologies used for identifying and ranking thesafety problems. Phases of the inspection procedureshave been defined. For each phase, objectives of theinspection, needed equipments, inspectionmethodology and roles of each team member havebeen defined and are synthetically described in thepaper. Moreover, criteria for identifying and rankingsafety issues are reported. Last, the review reportcontents and format are described. The procedure hasproved to be effective to identify most safety issues. Asa research outcome, a RSI operative manual has beenedited. It allows to transfer to other road agencies theacquired knowledge and to obtain a greater objectivityin the inspection process.

By the combination of results coming from the theoretical-experimental models for the evaluation of alignment designconsistency and from the Safety Inspection process ofroad features a Safety Index (SI) was defined. It wasformulated by combining three components of risk: theexposure of road users to road hazards, the probability ofbecoming involved in a accident and the resultingconsequences should an accident occur.The SI model was verified comparing the ranking of riskcarried out by the model with the actual number of accidenton the same road sections.

2 ROAD SAFETY INSPECTIONS:

INTERNATIONAL EXPERIENCE

2.1 USAIn 1996, the Federal Highway Administration (FHWA)dispatched a scanning team to evaluate the road safetyaudit process in Australia and New Zealand to investigatetheir applications of Road Safety Audits (RSAs) and todetermine if that tool would have added value in advancingU.S. safety practices [FHWA, 1997a]. The proactive RSApractice and its wide acceptance were recognized by theteam as adding value to road safety practices [FHWA,1997b.]The program participants recommended that a UnitedStates pilot study be conducted. Subsequently, the FHWAstarted a Road Safety Audit Pilot Project in 1998. Theproject began by auditing road projects. The application ofRSAs and RSARs is in its infancy in the United States, withonly a few states having safety pro-grams that includeeither an RSA or RSAR component. However, as a resultof training, more states appear to be willing to try theseapproaches to enhance safety. In particular, thirteen statesindicated the Road Safety Audit Reviews were part of theirstate’s safety program [TRB, 2004].FHWA indicates RSAs and RSAR such as new tools whichserve to bring an improved understanding of crash causeand countermeasures to bear in a proactive manner. Well-documented experience in Europe, Australia, andelsewhere shows that they are both effective and costbeneficial as a proactive safety improvement tool. Inparticular, post-construction road safety audits aims toevaluate all roadway and roadside features, designelements and local conditions (glare, night visibility,adjacent land uses, etc.) that would increase the likelihoodand severity of a crash [FHWA, 2006].

2.2 CanadaIn Canada, road safety audits have been introduced indifferent form across the country. In 1998, the Insurance

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Corporation of British Columbia released a DraftDiscussion Document to raise awareness and stimulatea discussion on audits [Halmiton Associates Consulting,1998]. In 1999, the University of New Brunswick issuedthe Road Safety Audit Guidelines document [Universityof Brunswick TG, 1999], drawing on the auditexperiences in New Brunswick.Furthermore, In British Columbia, a criterion for a driver-based evaluation of road safety risk was developed.The process is based on well-defined and quantifiablecharacteristics of road features that are studied andscored during a drive-through review. These scores arecombined to produce a safety index, formulated bycombining the exposure of road users to road hazards,the probability of becoming involved in a collision, andthe resulting consequences should a collision occur.Specific and combined risk indices are assessed. Thespecific index defines the risk associated with eachroad feature, while the combined risk defines overallrisk. The methodology can effectively support safetyreview results. Nevertheless, it requires input data thatin many instances are not available to the review team.[De Leur et al, 2002].In 2001, the Canadian Road Safety Audit Guide [TAC,2001] has been released. The guide addresses bothdesign audit and safety inspections, defined as “inservice”. Only in 2004 specific Canadian Guide to In-Service Road Safety Reviews was edited for theTransportation Association of Canada [TAC, 2004].Canadian guidelines are very comprehensive anddefine both inspection procedures and their interactionwith Safety Management system. Its worthwhile to pointout that human factors review was specificallyaddressed as part of the procedure.Existing roads safety reviews are intended as a mean toaddress potential collision risks before collisions startoccurring. To date, both in urban and rural area,numerous reviews of existing facilities have beenundertaken.

2.3 AustraliaIn 1994, Austroads released a broad set of guidelinesfor a national road safety audit program [Austroads,1994] , which has been revised in 2001 [Austroads,2001]The guidelines specifically address the safety review ofthe existing roads. The aim is to ensure that the safetyfeatures of a road are comparable with the functionalclassification of the road, and to identify any featurewhich may develop over time into safety concern[Jordan p., 2002] Regular audits of existing roads allowroad safety hazards to be identified before they result inaccidents.Two levels of inspection are defined: the preliminarylevel and the detailed level. The first level involves abroad assessment of the route, highlighting what majorproblems exist and where they are located. The secondlevel follows, with an inspection of the selected problemlocations in more detail, highlighting specific issues andmaking specific recommendations.Austroads states that ideally a program of safetyreviews that covers every road in the network should bedeveloped. Individual states are incorporating roadsafety audits at different rates throughout Australia. InNew South Wales twenty percent of existing roadwayswithin all regions are to be audited to identify

deficiencies in existing roads and identify priorities foraction.In Australia, a formal auditor accreditation exists. Anauditor has to meet the following criteria:• have a minimum of five years experience in roaddesign, traffic engineering; or closely related road safetydiscipline;• have successfully competed a training courseapproved and recognised by the State Road Authority;• certify that he has maintained current knowledgeand experience in road safety auditing.To be a designated audit team leader or a senior auditor,an individual has to also satisfy the following criterion:• have participated in at least five road safety auditsunder the guidance of a senior road safety auditor.

2.4 New ZealandIn New Zealand, safety reviews of existing roads havebeen extensively carried out in the last decade. ATransfund manual of safety audits of existing roads definesa risk assessment procedure that involves the prediction ofthe frequency and severity of potential accidentsassociated with each problem identified in the audit report[Transfund, 1998]. A matrix is provided on which one axisis the exposure to risk and the other axis is the severity ofthe expected crash. The cells of the matrix are filled withwords such as “low,” “medium,” and “high” level ofimportance. To assess the repeatability of the procedure,Transfund commissioned two independent safety audits ofthe same road network. The lack of common findings andthe variation in assessing risk level ratings raised concernsabout a lack of repeatability [Transfund, 2001] Transfundalso commissioned a study into the relationship betweenthe issues raised by auditors and actual traffic crashes.This work produced widely varying results and showed thatsome of the assigned risk ratings were not accurate.On the basis of these considerations, Transfund isdeveloping a rating methodology to improve the systematicquantification of the safety impact associated with theitems identified during safety reviews [Transfund, 2003].The method, although not definitive, is very well suited as asupport to the review process.A central record of existing road safety audits are retainedon a central database. The database has a number of uses[Appleton I. 2001]:• it enables authorities’ performances to bemonitored over time – hopefully they will improve;• it can record the implementation of the auditteams’ recommendations;• it can be interrogated for common recurringthemes. Transfund has started a series of articles thatdescribe these recurring themes and offer advice on howthey may be addressed.

2.5 EUIn 2002 The AA Foundation for Road Safety Researchlaunched its ”European Road Assessment Program”[EuroRAP, 2006], an European wide programme whosecore objectives are• to reduce deaths and life-treating injuries onEurope’s roads by systematically assessing risk andidentifying safety shortcomings that can be addressed withpractical road-improvements measures• to put assessment of risk at the heart of strategicdecisions on route improvements, crash protection andstandards of route management.

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It is a sister programme to the European New CarAssessment Programme (EuroNCAP) which awardsstars to roads for safety and produces maps describingrisk of traffic accidents on routes of states involved inthe project, as the starting point for a series ofdemonstration assessments or reviews. These reviewsare check-list based assessments of existing roads,concentrating on Safety Audit techniques rather thanhistorical accident data. Part of the EuroRAPprogramme is the development of a procedure for “drivethrough” inspections of routes carried out in speciallyequipped vehicles, in which inspectors assess andscore each road’s major safety features and hazards–the Road Protection Score (RPS).The RPS describes the protection from accidents that aroad provides (elements of primary safety) and theprotection from injury when collisions do occur(secondary safety). The results show where safetygains can be obtained and, where this is not costeffective, how some improvement can be made byreducing traffic speed [Lynam D. et al., 2004].The results of the project co-funded by the EU"Guidelines to Black Spot management: Identificationand Handling" [ERF, 2002] Road Safety Inspections areindicated like accidents preventive measures. The mainobjectives of the development of the inspections are todiminish accident frequency and severity, to reduce theaccident costs, to guarantee that every road haveoptimal safety conditions.The European Commission of the Directorate General'on Energy and Transport [EU DG_TREN, 2003]highlights the role of the RSI as part of a systematicapproach to road safety, evidencing as expectedbenefits from RSI application: the removal of roaddefects, the coordination of structures and pavingoperations maintenance, the safety improvement for allroad users, the implementation of low costsinterventions. The Directive aims to establishinfrastructure safety as an objective in its own right at allstages of the planning, design and use of roads [EUParliament, 2007]. A uniformly high level of safetyshould prevail on the roads of all the EU memberStates. Care must be taken to ensure that limitedresources are targeted to improving road safety. Toachieve these aims, the Directive proposes fourprocedures:

1. Impact assessment of the effect of roadbuilding on safety;

2. Safety Audits;3. Improving safety in existing road network;4. Safety Inspections, defined as regular

inspections of road infrastructure by trainedstaff that are a binding requirement.

To date, the Directive was not still approved.In quantitative terms the European Road Federation(ERF) assesses that 30 % of the problems identifiedduring RSI could transform itself in an accident causein the following 5 years [Papì J., 2005].

2.6 DenmarkSince 1997 Denmark applies road safety audit on newroad project for systematic prevention of roadaccidents, according to the procedures described in theDanish Manual of Road Safety Audit [Road Directorate,1997].In October 2000 the Danish Road Directorate launchedthe project “Road Safety Audit of Existing Roads”

[Langer K.A., 2001]. Such an audit is to be seen as asupplement, and not as an alternative, to other safetymeasures on existing roads, e.g. black spots treatment.The project concerns a road safety audit of a road sectionin Denmark of about 35 km on the island Lolland. Thestretch of road represents different types of roads:motorway, expressway, and highway with small villagesalong the route.In the fall of 2000, the road section was systematicallyinspected for all the matters that might be of importance tothe traffic safety. After the inspection, an audit report listingall commentaries and offering recommendations forpossible solutions has been prepared. The comments havebeen given priority according to the seriousness of therelevant traffic safety problems at three levels.

2.7 UKIn the UK the 1988 Road Traffic Act places a statutory dutyon local authorities to “carry out studies into accidents onroads”, and “to take such measures as are appropriate toprevent such accidents”.Since the early 1970’s many local authorities havetherefore undertaken work to identify high risk sites, andimplement “low-cost” improvement schemes. Much of thiswork has been monitored, and can therefore be shown tobe highly cost-effective.The UK government has set targets in terms of casualtyreduction since the 1980’s. In 1987 a target of a one-thirdreduction in road accident casualties was set for the year2000. This was met for killed and serious (KSI) casualtiesbut not for slights. In 2000 new targets of a 40% reductionin KSI, a 50% reduction in KSI for children and a 10%reduction in slights expressed as a flow based accidentrate were established for 2010. A 2001 U.K. publicationentitled Practical Road Safety Auditing was edited [ProctorS. et al., 2001].

2.8 NorwayExperience from completed road safety inspections inNorway shows that many roads have design faults that canlead to serious accidents. Undertaking road safety auditsthat can reveal such faults will be a central measure in theVision Zero effort. In 2003 the Directorate of Public Roadsmade an evaluation of results and experiences withundertaking road safety inspections of a total of 56 roadsections. Moreover, the Action Program for 2006 – 2015stated that the Public Roads Administration will intensify itswork on road safety inspections on national roads with highinjury severity density. In October 2006 the NorwegianPublic Roads Administration published the guidelineshandbook “Road Safety Audit and Inspections” [NPRA,2006] based on the “Preliminary guide for road safetyaudit of existing road and traffic projects” and additionalmaterial has been taken from “Development of road safetyinspection methods for existing roads”. The handbookcontains procedures, checklists and other information onhow road safety inspections of existing road shall becarried out.

2.9 AustriaRoad Safety Inspections in Austria are regarded as aperiodical controlling instrument of the existing roadnetwork (including roadsides), independently of number ofaccidents, which allows the implementation of remedialmeasures before accidents occur. However, selection of

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the same road network and the EB refinementtechnique was used to obtain a better estimate of theexpected accident frequency. The SI can be assessedwhether accident data are available or not. If accidentdata are available and are of good quality, the SI can beeffectively used in conjunction with accident frequencyas ranking criteria. If accident data are not available orare unreliable, the SI can be used as a proxy foraccident data and becomes the only ranking criteria.

REFERENCES

AASHTO. Roadside Design Guide. Washington, D.C.,1996

Appleton, I. Road Safety Audits. 14th IRF World RoadCongress, Paris, 11 – 15 June 2001

Austroads. 1994. Road Safety Audit. Sydney, NewSouth Wales, Australia.

Austroads, 2001. Road Safety Audit 2nd Edition.Austroads Publication AP-G30/02, Sidney,Australia.

Cafiso, S., La Cava, G., Montella, A., Pernetti, M., 2004.- A Methodological Approach for the SafetyEvaluation of Minor Two-Lane Rural Roads. In:Proceedings of the Conference European RoadFederation - 1st European Road Congress, Lisbon,Portugal.

Cafiso, S., La Cava, G., Leonardi, S., Montella, A.,Pappalardo, G., 2005. - Operative Procedures forRoad Safety Inspections. In: Proceedings of theConference Road Safety on Four Continents,Varsaw, Poland.

Cafiso, S., La Cava, G., Montella, A., Pappalardo, G.,2006a, “Una procedura per il miglioramentodell’efficacia e dell’affidabilità delle ispezioni disicurezza delle strade esistenti” XXV AIPCRNational Congress 4-7 Ottobre 2006 Napoli, Italy

Cafiso, S., La Cava, G., Montella, A., Pappalardo, G.,2006b, A Procedure to Improve Safety InspectionsEffectiveness and Reliability on Rural Two-LaneHighways. The Baltic Journal of Road and BridgeEngineering, Volume 1, No.3, pp. 143-150. ISSN1822-427X.

Cafiso, S., La Cava, G., Montella, A., Pappalardo, G.,2007a IASP Safety Inspection Manual. In press

Cafiso, S., La Cava, G., Montella, A., 2007b, “SafetyIndex for Evaluation of Two-Lane Rural Highways”TRANSPORTATION RESEARCH BOARD, 86thAnnual Meeting, January 21-25, 2007, WashingtonD.C. ,U.S.A.

De Leur, P., and T. Sayed. Development of a RoadSafety Risk Index. In Transportation ResearchRecord: Journal of the Transportation ResearchBoard, No. 1784, Transportation Research Board ofthe National Academies, Washington, D.C., 2002,pp. 33–42.

ESAS 2002. Empfehlungen für das Sicherheitsaudit vonStraßen ESAS, Allgemeines RundschreibenStraßen Nr. 18/2002 - Forschungsgusellschaft fürStrassen und Verkehrswesen, ArbeitsgruppeStrassenentwurf & Bundesministerium für Verkehr,Bau und Wohnungswesen - Bonn, Germany

EuroRAP sito web: http://www.eurorap.org, visited May2006.

European Transport Safety Council, 1997. – RoadSafety Audit and Safety Impact assessment,Brussels, Belgium

European Union Commission, DG Energy and Transport,High Level Group Road Safety, 2003. RoadInfrastructure Safety Management. Brussels, Belgium.

European Parliament, Committee on Transport andTourism, 2007, DRAFT REPORT on the proposal for adirective of the European Parliament and of the Councilon road infrastructure safety management

European Union Road Federation, 2002.. Guidelines toBlack Spot Management – Identification & Handling.Brussels, Belgium.

Federal Highway Administration, FHWA Study Tour forRoad Safety Audits, Part 1 - Final Report”, USA,1997a.

Federal Highway Administration, “FHWA Study Tour forRoad Safety Audits, Part 2 - Case Studies andChecklists”, USA, 1997b.

Federal Highway Administration, “Road Safety AuditsGuidelines, USA, 2006.

Fessl T., 2006, “Road Safety Inspection in Austria” Best inEurope Conference, Brussels, February 21-22 2006 inhttp://www.kfv.at

Hamilton Associates Consulting, Introducing Road SafetyAudit and Design Safety Reviews: Draft DiscussionPaper, Hamilton Associates, 1998.

Italian Ministry of Public Works Circular n.3669/2001: RoadSafety Audit Guidelines. Rome, Italy. 2001a.

Italian Ministry of Infrastructures and Transports.Guidelines for the Design of Road Infrastructures: D.M.n. 6792, 5/11/2001. Rome, Italy, 2001b.

Javier Saura López F., Careaga Miró E. & Crespo del RíoR. 2001.- - Auditorías de Seguridad Vial - AEPO,Ingenieros Consultores S.A., Área de Gestión deInfraestructuras

Jordan, P. 2002. “Putting road safety audit to workworldwide”, Routes/Roads n.314 II-, pp. 15-25

Lamm, R., B. Psarianos, T. Mailaender, E.M. Choueiri,R.Heger, and R. Steyer. Highway Design and TrafficSafety Engineering Handbook. McGraw-Hill, New York,N.Y., 1999.

Lamm, R., B. Psarianos, and S. Cafiso. Safety EvaluationProcess of Two-Lane Roads. A 10-Year Review. InTransportation Research Record: Journal of theTransportation Research Board, No. 1796, TRB,National Research Council, Washington, D.C., 2002,pp. 51-59.

Lamm, R., A. Beck, T. Ruscher, T. Mailaender, S. Cafiso,G. La Cava, and W. Matthews. How to Make Two-LaneRural Roads Safer. Scientific Background and Guidefor Practical Application. WIT Press, Southampton,United Kingdom, 2006.

Langer, K.A. 2001. “Road Safety Audit of Existing Roads”,Conference Traffic Safety on Three Continents, 19-21September 2001, Moscow, Russia,

Lynam D., Hummel T and Barker J, Lawson S. D. Hill J.2004. “EuroRAP Year I (2003) update - performancetracking of roads” Traffic Engineering and Control,September.

Norwegian Public Roads Administration 2006 “Road Safetyaudit and Inspection guidelines” Handbook 222,Norway

Papì J. 2005. Engineering Safer Roads:A look at EuropeanPolices and Practices“ EU-Serbia Seminar, Cacak,Serbia.

Proctor, S., M. Belcher, and P. Cook, Practical RoadSafety Auditing, Thomas Telford Publishing, London,United Kingdom, 2001.

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Road Directorate Ministry of Transport Denmark, 1997.Manual of Road Safety Audit. Copenhagen, DK.

SETRA, 1998. The Design of Interurban Intersectionson Major Roads. At-grade intersections. BagneuxCedex, France.

Siegel, S., Castellan, N. J. Jr, 1988. Nonparametricstatistics for the behavioral sciences. Boston, MA.,McGraw-Hill.

Transfund New Zealand, 1998. Safety Audit Proceduresfor Existing Roads. Transfund Report RA97/623S,Wellington, New Zealand.

Transfund New Zealand, 2001. A Review of TwoIndipendent Safety Audits of Existing Road Networkin Manawatu District. Transfund ReportOG/0901/4S, Wellington, New Zealand.

Transfund New Zealand, 2003. Safety Audits of ExistingRoads: Developing a Less Subjective Assessment.Transfund Report OG/0306/24S, Wellington, NewZealand.

Transportation Association of Canada 2001, “TheCanadian Road Safety Audit Guide”.

Transportation Association of Canada, 2004.. TheCanadian Guide to In-Service Road SafetyReviews. Ottawa, Canada.

Transportation Research Board 2004. NCHRPSynthesis 336 – Road Safety Audit – A synthesis ofHighway Practice.

University of New Brunswick Transportation Group,Road Safety Audit Guidelines, University of NewBrunswick Transportation Group, Canada, 1999.