Road safety can be assessed in terms of the social costs of crashes and injuries. However, simply counting crashes or injuries is an imperfect indicator of the level of road safety. When crashes occur it is the “worst case scenario” of insecure operational conditions of road traffic. Work Package 3 of SafetyNet deals with Safety Performance Indicators (SPIs). A Safety Performance Indicator is any variable, which is used in addition to the figures of crashes or injuries to measure changes in the operational conditions of road traffic.
SPIs can give a more complete picture of the level of road safety and can detect the emergence of problems at an early stage, before these problems result in crashes. They use qualitative and quantitative information to help determine a road safety programmes’ success in achieving its objectives.
Goal
One of the main goals of SafetyNet WP3 is to develop a uniform methodology for measuring a coherent set of safety performance indicators in each of the 25 Member States and some non-EU Members. This report provides the first ideas from the WP3 team on this subject.
The SafetyNet team will move on to the other goals (offering technical assistance to some Member States that fail in producing the SPI data according to the developed uniform methodology & collecting current data on SPIs that meet the standards of the uniform methodology) at a later stage in the project.
Research areas
Work Package 3 of SafetyNet investigates SPIs in seven different road safety areas.
- Alcohol & Drug use
- Speeds
- Protective systems
- Daytime Running Lights
- Vehicles
- Roads
- Trauma management
State of the art report
This report starts off with a description of the general methodology. Then, the report describes the state of the art in the seven research areas. Firstly, the theoretical backgrounds of each research area are given. Secondly, the first results from the questionnaire (that was sent to 27 countries: the 25 EU Member States, plus Switzerland and Norway) are presented. And thirdly, the first ideas on the details of the SPIs that could be used in the future are described.
Summary per task
Task 1: Alcohol & Drug use
Driving under the influence of alcohol and drugs is one of the most important factors increasing the risk of severe road crashes because impaired road users are likely to be reckless and to behave inadequately when a dangerous situation appears. Moreover, impaired road users may also be more vulnerable to physical impacts caused by collision. Better knowledge of the prevalence of alcohol and drugs among road users will contribute to the understanding of crash risk and to the need for counteraction, such as legislation, enforcement, and information. Task 1 concerns the development of Safety Performance Indicators for the use of alcohol and drugs in road traffic.
Somewhat less than half of the 27 countries indicated that they have data on alcohol prevalence among injured or killed drivers, and 4-6 countries have data on drug prevalence for such drivers. Based on these data, a SPI is proposed: the percentage of road users involved in fatal crashes and impaired by alcohol or drugs.
Data should be collected from the remaining countries to check to what extent using of the proposed SPIs in the future is possible. A detailed protocol for the SPI still has to be elaborated.
Task 2: Speeds
Driving speed is an important factor in road safety. Firstly, driving speed is directly related to crash severity. Secondly, driving speed is related to the risk of getting involved in a traffic crash. Thirdly, crash rate is not only related to absolute speed, but also to speed dispersion.
The collection of speed data is often initiated by other motives than road safety alone such as traffic management and planning. It is clear that collection of speed data can help decision makers in the field of road safety to monitor safety interventions on specific road types and to make specific comparisons to study factors relevant to safety.
From the 27 countries, 17 countries responded to the questionnaire, and from these 10 provided data to all items required. This probably indicates that information about speed data is not easily accessible at a centralized source. Considering the desired properties of the speed SPI, we proposed a central tendency measure of the data and another considering its variability. The use of standardized average and/or median speed and absolute deviation will need further testing and validation across the set of countries, once the data is available, depending on levels of disaggregation and possible exposure variables. The issue of comparability may imply further adjustments in the suggested indicators, and the weighing procedures shall be validated.
Comparative assessment of road safety in a European countries and regions relies on a unified methodology for the measure of exposure, i.e. for the vehicle kilometres. The concept of speed SPIs has been inspired by the same philosophy and therefore shares the dependence on a valid and reliable methodology for exposure measurement.
Task 3: Protective systems
The human body is vulnerable and, during crashes, is exposed to immense forces leading to injury or death. Here, the protective systems available for all traffic participants (airbags and safety belts) play a very important role in protecting the most vulnerable parts of the human body. Availability and appropriate use of protective systems are therefore fundamental items in developing this SPI.
The rates of protective systems use vary significantly with age, sex and other socio-economical characteristics of their users. These argue for treating different road users group in order to understand the problem better and find out the general rate for the whole population. Moreover, subdividing wearing rates is important for the target group concerning information and education, and enforcement activities.
Based on current practices, a set of Safety Performance Indicators has been proposed. The indicators for task 3 are the wearing and usage rates of protective systems by road users in road traffic. As the importance of particular devices derives mostly from their safety potential at national and European level, they may vary significantly among each other. The choice of the appropriate ones should be based on sophisticated research knowledge and not only on the accessibility and measurability.
The total number of chosen SPIs might be further reconsidered, as it’s quite high and requires a broad knowledge of the traffic situation and detailed survey information, which might recently not have been available for many countries.
Task 4: Daytime Running Lights
Many traffic crashes occur because road users do not notice each other in time or do not notice each other at all. This is true not only for traffic crashes in the dark but for traffic crashes in daylight as well. Vehicle visibility is therefore one of the factors which affects the number of crashes. The basic idea in developing the SPI for Daytime Running Lights (DRL) is the relation between the level of use of DRL and the size of the effect on safety (The daytime visibility of motor vehicles cannot be measured directly but the level of use of DRL can).
An indicator for DRL can thus be considered an indirect indicator for visibility. For this sub-problem an appropriate indicator was developed. The indicator is based on the relation between the level of the use of the DRL and the effect on multiparty daytime crashes (MPDA). The indicator has been identified on the basis of literature survey and the current practice.
Task 5: Vehicles
The SPI that this task is concerned with relates to the level of protection afforded by the vehicle fleet in each EU Member State. Where system failures lead to a crash, the potential of the vehicle itself to prevent (or indeed cause) injuries can determine whether the outcome is a fatality or something much less serious. The insecure operational condition could be defined as the presence within the fleet of a number of vehicles, which will not protect the occupant well in a collision. What is needed is a measurable variable that will tell us what this number is, and what proportion of the fleet it represents in each Member State.
It was possible to find an indirect indicator for measuring passive safety. More modern European vehicle fleets that have state-of-the-art vehicle designs should theoretically result in reduced casualty levels. It is generally recognised that cars designed to meet EuroNCAP test procedures are more robust and therefore offer better protection to vehicle occupants in comparison to vehicles that were designed before the development of the EuroNCAP test programme.
Of the 27 countries, 14 have sent a complete answer. For at least 8 countries it will be possible to assign a EuroNCAP rating to the vehicle fleet in order to calculate a performance indicator for vehicles (passive safety). For at least 6 others it will be possible to calculate a simple general indicator based on either fleet mix, vehicle age or both. It is proposed that a pilot study be performed using a country whose data can be used for all three of these SPIs, and on that basis the three indicators can be compared for their accuracy and usefulness.
Task 6: Roads
Infrastructure layout and design has a strong impact on the safety performance of the road transport system. Many ongoing practises in infrastructure research apply sampling of casualty data for safety assessment. In addition, crash prevention can be improved by early assessments of safety hazards e.g. by monitoring the physical appearance of the road environment and the operational conditions of traffic. This is what Safety Performance Indicators (SPI) dedicated to roads are aiming at.
A methodology for network description and (safety related) road classification has been developed, that is assumed to be suitable for international harmonisation. As a basis, the functionality of a connection (consisting out of one or more road types) and a systematic combination of present (safety related) characteristics has been used.
At this stage of the project only a few countries are able to provide requested data on both connection types, road types and other road design characteristics. Part of this may be due to the fact that no complete systematic information on the performance of the roads is routinely available in the majority of countries. Hence, special efforts will need to be undertaken to collect these data.
Based on the present country responses it can be stated that the suggested sets of SPIs seem to be realisable and promising for comparing road networks and road design in the Member States.
Task 7: Trauma management
The better the post-crash care by emergency and medical services, the greater the chance of survival and, on survival, the quality of life. The same goes for the opposite: Improper functioning of the post-crash care system leads to more fatalities and severe injuries, which could be avoided. The term "Trauma Management" refers to the system, which is responsible for the medical treatment of injuries resulting from road crashes.
No complete systematic information on the performance of the trauma care system and on outcomes of road crash survivors is routinely available in the majority of countries. Hence, special efforts will need to be undertaken to collect this data. The state and forms of the post crash trauma care differ among the countries. These differences should be accounted for in estimating SPIs.
Only some countries are able to provide detailed data on the performance of different steps of the post crash chain of care. The majority of countries may provide only general figures on the availability of services but not on the characteristics of their functioning. Therefore, two sets of SPIs should be recommended for the application: an initial (reduced) set, which can be filled in by the majority of countries today, and an extended set, which should be available in the future, with the perspective to provide a comprehensive picture of the performance of the trauma management system in the country.
Based on the SPIs estimation for the countries, which answered the questionnaire, we conclude that the suggested sets of SPIs seem realisable and definitely promising for comparing the trauma management systems in different countries. The primary data should be collected and the trauma management SPIs be updated on an annual/bi-annual basis.
Conclusion
This report is the first Deliverable from SafetyNet WP3. In the next months, this report will be updated with new data from the questionnaire, and the SPIs will be elaborated. This will eventually result in a common framework of SPIs: tools that can be used for monitoring road safety in Europe.
