Problem analysis
Road safety problems fall into 3 categories and are spread throughout the traffic system [63]
- First order problems appear at a superficial level of analysis – e.g. ‘the crash risk of young drivers is too high’.
- Second order problems are revealed by deeper analysis – e.g. ‘the access of novice drivers and riders to motor vehicles is too early’. They show up after closer analysis of first order problems and may reduce the effectiveness of countermeasures aiming at solving first order problems.
- Third order problems deal with underlying conditions that impede possible solutions to the first and second order problems e.g. inadequate resource or absence of co-ordinated intervention to reduce young driver and rider injury.
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Key system risk factors
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Human
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Vehicles and equipment
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Road
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Exposure
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licensing
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availability of high performance motor vehicles
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land-use planning, user mix
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Pre-crash
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crash occurrence
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speeding, impairment
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poor lighting, braking, handling, speed management
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poor road design or layout, absence of speed limits and pedestrian facilities
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Crash
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injury during the crash
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non-use of restraints and helmets
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poor crash protective design
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absence of forgiving roadside (e.g. crash barriers)
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Post-crash
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post crash injury
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poor access to care
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poor evacuation
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absence of rescue facility
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Table 1: System risk factors
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Effective targeted road safety planning is based on past and present road safety data; reasonable assumptions about the future; and broader factors which influence safety solutions such as the state of the economy or the national capacity for delivering safety work [50, 44] Several published examples illustrate how to set challenging but achievable targets and how to translate national into regional and local targets [2, 34, 35, 7].
- Crash data analysis is needed of crash location and time, road user group involvement, collision-types, and contributory factors to crashes, injuries and injury consequences.Past casualty trends over the previous 10 years need analysis;
- Assessment of the levels of risk for each road user group requires exposure data such as population numbers, passenger kilometres, vehicle kilometres, time travelled to provide crash and injury risk data.
- Assessment of future long-term casualty, traffic and demographic trends. New safety challenges can arise during the programme term. Although not an easy relationship to study a meta-analysis has shown that in certain circumstances rising or falling traffic volumes can have a large effect on road safety. In this study, the number of fatal crashes increased by around 25% when traffic increased by 100% [62]. In several countries, the increasing popularity of motorcycle travel is being accompanied by increases in deaths and serious injuries to this user group. An ageing population or changes in numbers of high-risk groups such as young males can also have an effect.
- Analysis of the effectiveness of countermeasures nationally is needed.Public opinion survey data informs about the acceptability of potential measures. The European SARTREis a cross national study of attitudes to road safety.
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