Road Safety Manual
A manual for practitioners and decision makers
on implementing safe system infrastructure!
Road Safety Manual
A manual for practitioners and decision makers
on implementing safe system infrastructure!
This section provides guidance on the establishment and maintenance of crash data systems. Information on the collection and use of other sources of data can be found in the following sections. Full details on the establishment and maintenance of crash data systems can be found in WHO (2010). The following is a summary of key issues.
Identified effective practice acknowledges that no single crash injury database will provide enough information to give a complete picture of road traffic injuries or to fully understand the underlying injury mechanisms (IRTAD, 2011). A number of countries which have improved their road safety performance use both crash injury data collected by the police as well as health sector data.
National crash data are typically collected by police (WHO (2013) reports that over 70% of countries use police data as the primary source), and entered into crash database systems for easy analysis and annual reporting. In some circumstances, data are collected from hospitals, or from both of these sources. The use of health sector data for meaningful injury classification at country level is necessary to complement police data and to provide an optimal means of defining serious injury. IRTAD (2011) recommends that police data should remain the primary source of road crash statistics, but that this should be complemented by hospital data due to data quality issues and to identify levels of under-reporting (see Section 5.4). Furthermore, in-depth data is needed from crash injury research to lead to meaningful conclusions concerning crash and injury causation.
The police are well placed to collect information on crashes as they are often called to the scene. Alternatively, they may receive information about the crash following the event. Attendance at the crash scene allows for collection of detailed information that is useful for identifying crash causes and possible solutions.
A crash report form is typically completed (traditionally a paper-based form, although recently computer-based systems have been used), allowing collection of quite detailed information on the crash. Key variables typically collected include:
Examples of crash report forms, including the types of detail that should be collected as a minimum can be found in WHO (2010). The advice provided in the WHO document is based on the European Common Accident Dataset (CADaS). In addition, a number of countries have developed their own minimum criteria. For example, the US has a Model Minimum Uniform Crash Criteria (further information is available on a dedicated website at http://www.mmucc.us/).
A balance needs to be reached between collecting the required information, and the time it takes to perform this task. If too much burden is placed on the police, it is less likely that the crash report form will be completed. Police are key stakeholders in the establishment and continued collection and use of crash data, and should be included at each stage of the process.
Hospital data is used to identify levels of under-reporting or to obtain better injury information, particularly when police report data is not available or is inadequate. IRTAD (2011) suggests that because of under-reporting of crash data, hospital data should also be collected, and is the next most useful source of information for crash statistics.
Encouraged by the WHO and other institutions, medical authorities have established international recording systems that include road traffic injury. In particular, the International Classification of Diseases and related Health Problems (ICD) and the Abbreviated Injury Scale (AIS) coding systems are used widely. IRTAD (2011) recommend that an internationally agreed definition of ‘serious’ injury be developed, and that the Maximum Abbreviated Injury Scale (MAIS) be used as the basis for defining crash injury severity. This scale is based on maximum injury severity for any of nine parts of the body. A score of 3 or greater for one or more regions of the body (MAIS3+) is recommended as the point at which an injury is considered to be serious. An example of the use GIS analysis and hospital data from Thailand is provided below.
A further example is provided in the case study from Egypt, demonstrating the integration of data from different sources, as well as the use of this data by various key stakeholders.
‘Vital registration’ data can be used as a source of information on road deaths. This information comes from death certificates completed by doctors which state the cause of death. WHO (2010) reports that around 40% of WHO member countries collect vital registration data of the detail required for monitoring road traffic deaths. WHO and other organizations have instituted an international registration system that includes those injured in traffic crashes.
Other sources of data on crashes can come from emergency services, tow truck drivers, members of the public, insurance companies, etc. However, it is important to recognise that the quality and extent of this information may be limited when compared to police and hospital reported data.
Before establishing a new crash database system (or improving a current system), it is recommended that a situational assessment be undertaken (WHO, 2010). This involves:
These same steps are also required when establishing or improving on the collection of non-crash data (see Non Crash Data and Recording Systems).
A stakeholder analysis involves identifying organisations and individuals who have (or should have) a role in the collection and use of road safety data. Critical stakeholders will include police, transport agencies and health departments, but there are likely to be many others.
An assessment of data sources is required to determine what information is already collected, and the quality of the data. This is often a significant problem in many countries.
An end user assessment involves understanding who the key users are and, how these key stakeholders use the information. This knowledge will help improve the usability of the data.
An environmental analysis involves understanding the political environment and critical partnerships required for the successful collection, analysis and use of the data. Without this understanding and appropriate collaboration, it is likely that collection and use of crash data will be severely hindered. There are many examples where expensive crash data systems have been established, but data has not been entered into the system due to inadequate communications and poor cooperation.
Following this situational assessment, the recommended process for establishing a crash database system is to:
Crash location is a key element in collecting and analysing data, particular for road engineers. Without this information, it is not possible to determine what locations to treat in the future. In addition, if the crash location is known (whether from police reports or other sources of data), there is potential to link this crash data to asset or other data sources (see Analysis of Data and Using Data to Improve Safety). This information may be of use in identifying other road-based elements that may have contributed to the crash risk.
Several methods are available for the accurate location of crashes, including the use of global positioning systems, reference to a local landmark (e.g. a link-node system), or reference to a route kilometre marker post (a linear referencing system).
Historically, crash data records were kept in paper-based filing systems, but now computerised database systems are used to store information on crashes. This allows relatively easy analysis of data, and is particularly useful in the identification of trends, high risk locations or areas, key crash types, etc. There are a number of computer software packages available for this task. At a minimum, such a system should have the capacity to:
Crash data systems have become very advanced in recent years, with features added that allow quicker and more useful analysis. WHO (2010) and Turner and Hore-Lacy (2010) provide a list of other desirable features of crash data systems. These include:
An example of the successful implementation of a crash data system is provided in the case study below from Cambodia.
The Swedish Strada system is a unique database that integrates police and hospital data. It is important to recognise that although this linkage provides valuable additional information, it does occur at additional cost. Further details are provided in the Swedish case study.
Some countries have undertaken in-depth studies of serious crashes to provide a more thorough understanding of crash causation factors and possible solutions. Such studies typically investigate a sample of high severity crashes. As an example, in the UK, the ‘On the Spot’ project collected detailed and high-quality crash information over two regions. More than 2000 variables were collected for each incident based on scene investigation soon after the crash occurred, as well as follow-up communication with medical services and local government. The information was analysed to provide insight about human involvement, vehicle design, and highway design in crash and injury causation. Mansfield et al. (2008) provide an initial analysis of around 2000 incidents from this program. Such investigation can provide far more detail than what is typically available through a crash report, and to a higher degree of reliability.
Similar examples can be found in many other countries, including the USA, Germany, France, Malaysia, India and Australia. Some of these programmes have been in place for many years, and have produced large amounts of valuable information. One of the key outputs from the EU DaCoTA project (which collected and analysed data from European countries on various road safety topics) was guidance on the collection of such data, as well as standardised procedures (Thomas et al., 2013). A Pan-European In-depth Accident Investigation Network has been established, and tools such as an online manual for in-depth road accident investigations have been developed (see http://dacota-investigation-manual.eu).
The US has established the second Strategic Highway Research Program (SHRP2). SHRP2 is perhaps the most comprehensive database of information on factors occurring before and during crashes and near-crash events. The information collected includes data from the Naturalistic Driving Study (NDS) database. This dataset includes information from over 2300 drivers, collected through equipment installed in their own vehicles, and through normal driving. The massive amount of data collected through the NDS is supplemented through the Roadway Information Database (RID) which includes comprehensive information on road elements in the study areas as well as other relevant data (including crash data). This globally significant database is expected to provide the research basis for studies on driver performance and behaviour. More information can be found at http://www.trb.org/StrategicHighwayResearchProgram2SHRP2/Pages/Safety_153.aspx.
UDRIVE is the first large-scale European naturalistic driving study using cars, trucks and powered-two wheelers. The acronym stands for “European naturalistic Driving and Riding for Infrastructure & Vehicle safety and Environment”. Whilst road transport is necessary for the exchange of goods and people. There are significant negative consequences to road safety and the environment. To meet EU Target crashes and vehicle emissions will need to be reduced, with new approaches to achieve these targets developed. It is the aim of UDRIVE to provide a better understanding road user behaviour leading to crashes and wasted vehicle emissions.
Sharing of data from different sources is required for the comprehensive collection, analysis and integration of data. Efficient data sharing, particularly between the police and the highway authority, is essential for good practice road safety management.
However, it is important to note that some organisations may be reluctant to share certain data, particularly personal identifiers, due to the issues it poses surrounding the privacy and anonymity of those involved. One response is to collect the personal details on a separate page of the crash report form (e.g. name and address information). This page can then be removed before sending the remaining pages on to partner agencies. In some cases, it may be necessary to develop appropriate privacy policies to ensure this issue is addressed, or for certain variables to be removed to prevent the identification of individuals.
Crash data on its own is a valuable source of information on crash risk, and when combined with other sources of data, this value can be greatly increased. The following section discusses some of the other data sources, while Analysis of Data and Using Data to Improve Safety discusses combining these sources.
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