AN APPROACH TO THE STANDARDISATION OF ACCIDENT AND INJURY REGISTRATION SYSTEMS (STAIRS) IN EUROPE

Transcription

1 AN APPROACH TO THE STANDARDSATON OF ACCDENT AND NJURY REGSTRATON SYSTEMS (STARS) N EUROPE R. Ross P. Thomas Vehice Safety Research Centre Loughborough University B. Sexton Transport Research Laboratory United Kingdom D. Otte Accident Research Unit Medica University Hannover. KoSmann Bundesanstat fiir Strassenwesen Germany G. Vaet J.L Martin B. Laumon nstitut Nationa de Rkcherche sur es Transports et eur SCcuritC P. Lejeune CETE - Sud-Oest-Ministere des Transports France Paper Number 9%S6-P-16 ABSTRACT STARS is a European Commission funded study whose aim is to produce a set of guideines for a harmonised, crash injury database. The need to evauate the effectiveness of the forthcoming European Union front and side impact directives has emphasised the need for rea word crash injury data-sets that can be representative of the crash popuation throughout Europe. STARS wi provide a methodoogy to achieve this. The utimate aim of STARS is to produce a set of data coection toos which wi aid decision making on vehice crashworthiness as we as providing a means to evauate the effectiveness of safety reguations. This paper wi disseminate the up-to-date findings of the group as they try to harrnonise their methods. The stage has been reached where studies into the diverse methods of the UK, French and German systems of crash injury investigation have been undertaken. An assessment has aready been made of the reationships between the three current systems in order to define the areas of agreement and divergence. The concusions reached stated that there were many areas that are aready cosey reated and that the differences were ony at the detaied eve. With the emphasis on secondary safety and injury causation, core data sets were decided upon, taking into account: Vehice description, coision configuration, structura response of vehices, restraint and airbag performance, chid restraint performance, Euro NCAP, Pedestrian and vehice occupant kinematics, injury description and causation. Each variabe was studied objectivey, the important eements isoated and deveoped into a form that a partners were agreeabe on. A gossary of terms is being deveoped as the project progresses which incudes S0 standards and other definitions from the associated CAREPLUS project, which addresses the comparabiity of nationa data sets. A major consideration of the group was the data coection method to be empoyed. The strengths and weaknesses of each study were investigated to obtain a cear idea of which aspects offered the best way forward. The quaity of this information and transference into a common format, as we as the necessary error checking systems to be empoyed have just been competed and are described. n tandem with this area of study the probem of the statistica reationship of each sampe to the nationa popuation is aso being investigated. The study proposes a mechanism to use a sampe of crash injury data to represent the nationa and internationa crash injury popuation. 1298

2 NTRODUCTON: Researchers, manufacturers, insurers and reguatory bodies a have a roe to pay in the area of vehice crashworthiness. Each has an individua approach to this area and uses simiar information as a base for their judgements. However, none of the parties has the benefit of a the information that coud be avaiabe. Three separate eves of coection systems are currenty in pace in severa EU countries. The first represents the Nationa crash injury popuation - the accidents that occur throughout a country that meet certain criteria for incusion. These criteria are different for each country and are not necessariy comparabe. The second eve forms a speciaist database; insurance companies are the argest of this group and can incude data from more than one country. However, a ot of the information is sef reported and the quaity of the information, incuding injuries, may not be of the required standard. The fina eve is derived from n-depth investigation systems. These incude a high degree of detai, but consequenty they may be more imited in number of cases. They aso are derived from a set of incusion criteria initiay based on the crash notification process, pus other additiona samping variabes (e.g. the presence of an injury). t woud obviousy be preferabe if a these systems were in some way compatibe so that a better view of the overa situation coud be observed. The aim of STARS is to give hep and guidance at the indepth eve and to produce a set of data coection toos for: 1 ~p-c-y-q Research based vehice safety poicy-making, Measuring the effectiveness of vehice safety reguations, Measuring the effectiveness of new safety systems, dentifying the need for new/revised vehice safety reguations, dentifying areas requiring further research. n order to progress this task, three of the argest in-depth investigation studies in Europe are being used: The Medica University of Hannover (Germany), The Co-operative Crash njury Study (UK), and NRETS (France). Two areas of study were identified. The first concerns the actua data coection process; the second is the statistica probem of inking the in-depth sampe to the nationa dataset. The first work package has seven tasks to compete (See Figure ), and deas with the coection process. nitiay the three different systems of each country were assessed in order to find the strengths and weakness present, as we as ooking at the initia eve of compatibiity that aready existed between them. Foowing this, a nuceus of data had to be identified aong with the coection methodoogy to be used. Reevant, practica quaity checks were then identified concerning the accuracy of the data. A sma piot database was then coected in order to vaidate the previous steps, and finay the handing of sensitive data within the confines of each country s data protection aws was deveoped. Specification Data coection Data of core data methods quaity Figure 1. Work package one fowchart. 1299

3 The second work package is designed to draw up a protoco so that a generaisation of the resuts from in-depth investigations can be reated to the Nationa database. The same three studies are being used to formuate this inkage. The tasks to compete in this work package are: Samping and case seection, Comparabiity of data Correct usage of the databases. The initia probems to overcome is the statistica reationship between the in-depth, oca and nationa databases. A methodoogy is to be devised to take into account the biases between each of these databases so that a ink can be made to nationa eve, the imit of STARS. There wi be, within the overa strategy of this package, a connection to the CAREPLUS system so that a ink between the Nationa and nternationa databases wi be feasibe. WORK PACKAGE ONE. Work Package Review of existing n-depth studies: Germany has the ongest running, consistent, singe programme having commenced in 1973, coecting fu in-depth data from1985. The coection area is bound by the common border of Hannover, approximatey 2,289km. t has a popuation of 1.2 miion and is fairy representative of the nationa popuation in terms of its percentage of urban to rura areas. The study uses an on-scene, intime coection methodoogy and has speciaists in the injury, vehice mechanics and road environment fieds to coect the data. The UK study CCS (The Co-operative Crash njury Study), began in 1983 athough previous indepth studies had been in existence since the sixties. There are two main coection teams based at Loughborough University (The Vehice Safety Research Centre), and Birmingham University (Birmingham Accident Research Unit). There are a series of six smaer groups, the Vehice nspectorate, in other areas around the country. The project is managed by the Transport Research Laboratory (TRL). A information is coected in the same manner retrospectivey. This entais going to investigate the vehice at a recovery yard some days after the crash and taking a the necessary measures. This information is then coated with the injury information from the hospitas. France has had different coection systems in pace ever since the sixties. However the current arge scae project ony began in t consists of four teams. Two beong to The nstitut Nationa de Recherche des Transports et de eur SCcuritC (NRETS), at Saon-de-Provence, and Lyon., the other two beong to the Centre Europeen de Securite et d Anayse des Risques (CEESAR), and are ocated in Amiens and Evreux. A the teams coected their data in the same way unti recenty. The methodoogy used is on-scene, in-time and incudes a strong Primary Safety eement with information on driver behaviour coected by a psychoogist. Recenty, the centre at Lyon has begun to coect its data retrospectivey, athough the information coected is simiar. The impact of this change has yet to be assessed. A three studies have common objectives, in particuar, regarding the assistance given to poicy makers and industry. This incudes assessing the need for new reguations as we as the efficiency of the current aws. Each of the separate databases are aso used to monitor new safety mechanisms, such as airbags or side impact bars, to see if they have affected the injuries sustained in different types of crashes. However, each study does have its own individua aims and objectives. The German study concentrates on the injury pattern and considers the efficiency of the emergency services in handing injuries and their outcome, whie the French have a deep interest in the drivers psychoogica behaviour, and the UK study focuses on secondary safety and injury causation. Athough there are these divergent areas of interest, there is immense potentia for convergence as coecting detaied descriptions of deformations and injuries and other main methods are entirey compatibe, with the differences being in the detai. This is due to the individua aims of each study and need not be compromised to achieve compatibiity. A series of variabes are common throughout the studies, but the interpretation of the exact meaning is sighty different. f a gossary of terms coud be agreed as we as the method of coection, then there are no reasons why steps cannot be made towards compatibe systems within each country. 1300

4 Work Package Variabes and vaues: This work package seeks to define a group of variabes, upon which a partners agree, and which are essentia for a detaied accident database. The data is a minimum set and it is expected that groups wi add extra detais or extra variabes to refect particuar interests. However it shoud be possibe to reduce any enhanced dataset down to the STARS eve without ambiguity. nitiay each partner put forward a ist of the variabes they deemed necessary for the above. Discussion took pace unti there was consent as to the exact interpretation of the variabes meaning. This has, on certain occasions, necessitated the variabe to deveop into a new form that none of the current systems coect, but with the abiity to be compatibe with the od formats in each of the databases. f an internationa standard was aready in pace then it was, if possibe, adopted and integrated into the ists. The intent is not to re-invent the current coection systems, but to provide the opportunity of deveoping a new one. The document is set out in a ogica manner beginning with: accident configuration, foowed by the vehice description, pre- and post-crash measurements, seats (incuding chid restraints), intrusion, pedestrians, casuaty and finay the injury section (See Tabe 1) VARABLE Accident Detais Number of Peope Pre-crash Measurements Doors VARABLE Number of Vehices Vehice Description Post-crash Measurements Seats t is envisaged that the variabes used are transferabe and can be enhanced to suit whatever area of interest is being investigated. Simiary, the ist is seen as moduar, with headings to be omitted or new ones added or enhanced as the user requires. The ist wi aso deveop with time, and is not to be taken as a rigorous, defined system. New areas are being added a the time, and the current ist incudes Euro NCAP variabes and other current EU-Commission research projects such as CREST, COST 327. Variabes have been added in the accident configuration section which reate to those coected at nationa eve. This is to enabe a ink between the in-depth investigations and the nationa databases. Many variabes that are extremey hepfu in defining coision types coud not be used as there was no comparabe equa across the participating countries. An exampe is that of type of road. The definitions within each country were based on competey different ines, from traffic fow to whether the road ies within a town boundary or not. These disparities were too great to overcome, but work is being done within the CAREPLUS programme that may hep in this area in the future. The Coision Partner Configuration tabe (See figure 2) was deveoped to enabe a quick reference to the type of vehices invoved. This idea of using a grid or matrix to refer to certain pieces of information which may incude a number of variabes has been used throughout the work package; from an intrusion matrix to the ocating of pedestrian contacts on the exterior of a vehice s bonnet. Occupant and njury Detais Singe njury Description Tabe 1 Document Variabe Headings The coision partner ist incudes a wide range of vehices, most of which are not covered in the body of the work. Figure 2 Coision Partner Configuration Tabe 1301

5 Many areas which are currenty very contentious were examined with a view to deveoping a new paradigm. However, it was accepted that some areas, such as refined methods to estimate coision speed, were too arge a subject for the STARS project to cover and outside of its remit. n other areas the current practice was deveoped and extended to produce a hybrid. The extra digits in the coision deformation measurements and in the AS injury descriptions are exampes of this. Others, such as intrusion, were deveoped to a esser degree but do give a starting point to work from. Essentiay STARS is concerned with secondary safety, and as such deas mainy with investigating the crashworthiness of the vehice. Particuar emphasis was paced on the presence of safety components and their effectiveness. This has necessitated taking into account current and proposed standards. Euro NCAP variabes are incuded throughout the document and consideration was given to the new side impact tests when the coision deformation measurements were discussed. Detais of chid restraints were aso incuded as this was deemed an area that wi require more investigation in the future. The body of the document is aid out with the variabe on the eft, foowed by the attendant vaues, and finay by a notes section (See figure 3). The notes section is intended to carify the meaning of either the variabe or the vaue or expain the protocos to be used when coecting the data. This is particuary reevant within the new systems detaied for intrusion, injuries and pedestrian contact ocation. There is a copy of the compete document on the Word Wide Web at the URL Coision condition Coision ange t- Percentage of the area of the concerned / vehice in contact with the obstace in the 1 crash ~-~ Ange foim ed by the ongitudina axes of the vehice and the obstace at the time of coision Longitudina axis to the front i.~ overturning to ; side - / 1 Main impact is to the upper area of the vehice whew it S mosty gazing 7 vehice position after the crash..-j ~ ~ --..._ i _ Figure 3 Exampe of a page from the Variabes and vaues document._l

6 WORK PACKAGE TWO. Combining the datasets from severa countries is compex. f the anaysis of the data were just used for inking injury outcome with vehice performance, then samping methods woud not be a probem. However, STARS is to be used as a too for a better understanding of the European crash popuation. n order to achieve this the case seection process must produce representative data. To ink in-depth data to a subset of the oca accident popuation, and from there ink to a subset of the nationa popuation, wi invove using weighting factors through a two stage process. Currenty ony working documents have been produced, but the foowing is a synopsis of the current situation. Both France and the UK are panning the inkage between their respective indepth databases and the appropriate oca/nationa databases by use of common variabes (see figure 4). n Germany the inkage to the oca accident database is possibe, but it may not be possibe to represent the nationa accident database due to the specia features of the oca sampe area. Figure 4 Linking databases. Variabe Weight Loca/Nationa Accident database in-depth to oca/nationa f a variabe of interest is ony coected within the in-depth database and an estimation of its distribution is required at nationa eve, the in-depth distribution wi be weighted by one (or more) variabes which wi scae the distribution to estimate the oca and then the nationa distribution. The weighting variabe(s) must be in common with the indepth and oca/nationa databases. Further, the weighting variabe wi reduce the samping biases which may be in the in-depth database. A check at each eve of the process shoud be made using a known outcome from a cosey reated variabe to ensure accuracy of the estimate. The foowing assumptions are made: n-depth database accidents are incuded within the oca/nationa database. The oca database may be a biased sampe of the nationa database. The in-depth database may be a biased sampe of the oca database. The question is then: s there any weighting variabe (wi) to reduce the bias from the in-depth to oca database. s there any weighting variabe (wj) to reduce the bias from the oca to the nationa database. s the weighting variabe the same in each case? (wi) = (wj). We expect wi and wj to be functionay reated to the variabe of interest. The probem is to identify those weighting variabes which are required for the variabe of interest and to demonstrate that their use reduces bias. The foowing points arise: The need to identify key variabes for weighting purposes. To identify types of variabes which woud use the same set(s) of weighting variabes. To use substitute weighting variabes when necessary, e.g. 6V is not a inking variabe so one coud use speed imit instead as the best avaiabe. To accept that there may not be suitabe weighting variabes and/or data in the in-depth database to provide an estimate. t is essentia to estimate the confidence interva on any estimate. Weighting from a sma in-depth database to a nationa estimate may be imprecise 1303

7 OTHER WORK PACKAGES. Further work in other areas is occurring simutaneousy but have not yet reached their concusions. Work Package 1.4 deas with data quaity and covers the areas of: Data coection, compiation of data, initia processing of eectronic data, and comparison of data from severa sources. The emphasis of the quaity aspect in this package is to ensure accuracy of data and does not mean that the data is necessariy avaiabe to answer certain questions. There are three eves within the data quaity process: Coection of the data. Coding of the coected data into an accepted format. 0 Anaysis of the data A set of fow diagrams have been produced that reay the primary principas expored within these three categories(see exampe figure 5). i ~..~~~.~~~~~. i w L...2 Coection Data New Area Coding of Team -* Coection a dentified -* nformation T Figure 5 The Coection : T!??!!.!?~.y 1 Loop These diagrams reate to an estabished group and identify the feedback oop necessary to ensure that the changing environment of vehice design and safety systems are identified at an eary stage. From this the appropriate training can be given to the investigators. This incudes any changes that may occur within the coding systems. The accuracy of data is the most important at the coection phase. Crash investigators shoud be proficient in the areas of impact kinematics, biomechanics and vehice examination. They shoud aso understand fuy a the toos at their disposa, and the circumstances in which each one is the most practica, efficient and accurate. The advent of eectronic forms of coection wi hep in this area, but ony insofar as the time taken and there wi be fewer transposition errors. The physica coection process and its inherent quaity probems wi not be soved by the use of computers. Concentration of the quaity management procedures shoud be directed at the coection end of the process to ensure the east degradation of information. n order to ensure that this happens the foowing recommendations shoud be appied: A baanced team shoud be seected, with the appropriate speciaists in pace. Training and a constant updating of skis necessary to ensure the high quaity of information coection shoud be a main priority. 0 A simiar process for the coding of the information shoud occur. A gossary of terms, updated as necessary, shoud be in pace with a cear, precise understanding of the terminoogy and conventions used. An objective method of recording data, such as photography, shoud be used either as the primary or secondary too for investigation. Putting the case together shoud have at east two stages: The initia methodoogy of bringing together a the separate parts; vehice information, injury detais etc., and which shoud incude a manua ogic check for sef consistency throughout. A second, more objective check made by personne not directy associated with the coection process. * Checks shoud be used to ensure that the data is transferred into an eectronic format correcty. A check for sef-consistency within the coding of the eectronic data shoud occur. There shoud be a management check. Data aso has to have a certain eve of user quaity ; that is the abiity to answer questions that may be asked of it. This area of quaity is determined by the prevaent areas of investigation at the time, which is in turn dictated by the overa aims of the funding body concerned. n order to be of use, a common database must have datasets from its contributors that cover a the reevant areas of interest, both poitica and socia, to such a eve that it can provide usefu information on any query that may arise. To ensure that this happens in a controed manner rather than in a haphazard fashion, reguar reviews of the core datasets shoud occur. 1304

8 Work package Confidentiaity and Ethics, is now at the stage whereby a the necessary information concerning the working practices in each country have been identified. Each country has its own set of aws at oca and nationa eves, deaing with this type of data. European egisation does exist and has been used as the foundation for this work package. There is however, broad consensus as to the handing of the sensitive information coected. The transfer and storage of confidentia data is subject to strict guideines concerning the avaiabiity, access and confidentiaity of the information. A partners provide for the secure storage of the written data. Eectronic data has to be anonymous and each system has in pace a means of removing direct references to the persons invoves in the crash and the vehices they occupied. From this a set of protocos can now be deveoped to set down best practise within this area; but with the fexibiity to aow for the oca differences that are present. A workshop is being organised for Work Package 1.5 in order to vaidate the protocos estabished and receive feedback from other interested parties. The date wi be within the week commencing 15 June 1998 at the European Commission buidings in Brusses. Work Package 3 invoves the dissemination of the information from the STARS project as a whoe. This has been achieved by the deveopment of a wide ranging database of companies, institutes, working groups and research estabishments that have an interest in the fied of vehice safety. The deiverabes from the work packages are distributed amongst these groups and feedback requested. Repies from this diverse section wi give an exceent range of repies as to the practicaity of the proposas and hep in the further deveopment of them. For any further information, pease contact: Mr. R. Ross. Vehice Safety Research Centre, Hoywe Buidings, Hoywe Way, Loughborough, Leicestershire. LE 3UZ Te: +44 (0) e-mai: rross@ice.co.uk Mr. G. Vaet. NRETS. 109, avenue Savador Aende, Case 24 F BRON CEDEX Te: e-mai: gies.vaet@inrets.fr Mr. D. Otte. Accident Research Unit Medica University Hannover, Car-Neuberg-Str. 1 D Hannover GERMANY Te: Fax: As any ist wi never be totay comprehensive, especiay in such a arge area as vehice safety, an avenue of contact has been provided in the shape of a word wide web site at: This site is intended to hod a the up-to-date information on STARS and aso the points of contact in each reevant country. 1305