A Review of the Delivery of the Road Safety Strategy - UCL Report

3: Target setting, accident data and research

The success of the road safety strategy will be measured mainly by the extent to which the targets are achieved, and in terms of the national road accident data. It is therefore relevant to look back briefly to the target setting process and to note developments in the road accident data system and the firm basis of the strategy in research.

3.1 The target setting process

It is appropriate to review briefly the national target setting process to ascertain whether, with hindsight at this relatively early stage in the target period and in advance of the DfT's own 3-yearly review to be undertaken during 2003, there are pointers to changes in strategy at either national or local level.

The numerical context for the setting of the current casualty reduction targets for 2010 is described by Broughton et al (2000). That work and its relationship to the rest of the development of the strategy are outlined in Appendix 3. The exact form of the target was a matter for decision by Ministers, and their eventual decisions about targets for numbers KSI and the slight casualty rate implied roughly an extrapolation to 2010 of the rates of reduction and increase respectively in annual numbers KSI and slightly injured over the period of the previous target. But the professional advice provided to them to help them in their decision was based on a wider range of considerations than simply experience with the previous target.

The method adopted for developing that advice was influenced by two considerations:

1 The Government's integrated transport policy (DETR 1998a) seeks deliberately to alter the trends of recent decades in road use by encouraging walking, cycling and the use of public transport whilst moderating growth in the use of cars.

2 The Government had committed itself to 3-yearly reviews of progress towards the target and of priorities within the strategy, so that the numerical basis of advice on target-setting had to be transparent and the calculations repeatable in the context of the reviews.

These two factors together meant that analysis had to distinguish explicitly between the effects upon future casualty numbers of safety policies on the one hand and changes in use of the roads on the other. Forecasts of future numbers of casualties were therefore made by:

1. forecasting casualty rates per unit of road use in the absence of new safety policies;
2. reducing the resulting forecast casualty rates to reflect the likely effects of new safety policies; and
3. applying these reduced rates to a range of possible future scenarios for road use.

These three steps are discussed in Appendix 3. The review team has considered to what extent the judgements made in carrying them out have been borne out by developments in the intervening 5 years.

Judgements made in the forecasting of casualty rates per unit of road use for various kinds of road user have been largely borne out, and in the few cases where slightly different judgements would be made now, the effect on the overall forecasts of numbers KSI or slightly injured in 2010 would be small.

Judgements about the likely effects of new safety policies on casualty rates were made separately for each road user group, leading to the following assumed aggregate effects on the numbers KSI.

Effects of measures of all these kinds combined multiplicatively - 35 per cent

These percentages were based partly upon estimates derived from research assembled by others contributing to development of the strategy, and partly upon aspirational judgements made by those responsible for the numerical work. With the benefit of hindsight, and in advance of the first 3-yearly review, which will be undertaken during 2003, the following comments on the percentages seem appropriate.


1. New road safety engineering programme - 7.7 per cent
2. Improved secondary safety in cars - 8.6 per cent
3. Other vehicle safety improvements - 4.6 per cent
4. Motorcycle and pedal cycle helmets - 1.4 per cent
5. Safety on rural single-carriageway roads - 3.4 per cent
6. Reducing accident involvement of novice drivers - 1.9 per cent
7. Additional measures to protect pedestrians and cyclists - 1.2 per cent
8. Additional measures to reduce speeds - 5.0 per cent
9. Additional measures to protect children - 1.7 per cent
10. Reducing casualties in drink-driving accidents - 1.2 per cent
11. Reducing accidents during long-distance work driving - 1.9 per cent
12. Additional measures for improved driver behaviour - 1.0 per cent

The percentage for the new road safety engineering programme is on the low side because the levels of funding for Local Transport Plans may well allow higher levels of expenditure on road safety engineering than was foreseen, and the cost-effectiveness of such work may well not decline as rapidly as was assumed. The percentage for improved secondary safety in cars is on the high side because the rate of progress towards this at the EU level, especially in respect of protection for struck pedestrians and cyclists, is slower than was assumed.

The percentage for motorcycle and pedal cycle helmets may be on the low side because of the increase in motorcycling.

The percentage for additional measures to reduce speeds was a judgement which it should now be possible to refine on the basis of work carried out for the speed review (DETR 2000b) and the policies for speed management included in and being pursued under the road safety strategy (DETR 2000a).

The percentage for reducing casualties in drink driving accidents is on the high side in the light of the Government's decision not to reduce the blood alcohol limit to 50mg/100ml.

In terms of the three main areas of influence contributing to casualty reduction the total of 35 per cent may be broken down (Allsop 2002) roughly as follows.

• vehicle engineering - 15 per cent
• road safety engineering - 13 per cent
• road user behaviour - 11 per cent

Developments in road use in the intervening years are well within the range covered by the scenarios that were used, except that the recent rate of growth in motorcycling is at the upper end of the range envisaged.

The results of this whole process can be interpreted as indicating that Ministers were quite cautious in setting the target for KSI and rather bolder in setting the target for the slight casualty rate. Caution derives from the fact that the estimates are based on continuation of past trends and the implementation in full of a wide range of policies - neither of which can be taken for granted - but it implies that all concerned should be thinking by how much the target can be exceeded, rather than merely how to reach it.

It can be expected that all the issues raised here will be considered by the first of the envisaged 3-yearly reviews of the strategy and targets, which is to be carried out in 2003 on the basis of traffic and casualty data to the end of 2002.

3.2 The national road accident statistics

The casualty numbers for which the targets have been set are those recorded in the national road accident statistics system known as STATS19. This system is reviewed every 5 years by a responsible body, the Standing Committee for Road Accident Statistics (SCRAS), in consultation with users of the data. The 2002 STATS19 review, whose report is nearing completion, was aware throughout its work of the importance of the STATS19 data for the monitoring of progress towards the casualty reduction targets, and its recommendations can therefore be expected to be consistent with this. They are also likely to include the adoption within STATS19 of a national system for recording of contributory factors which the reporting officer will be able to attribute to the accident being recorded. If this recommendation is implemented, the data on contributory factors are likely to be recorded from 2005 onwards and be available for analysis from 2006 onwards.

The background to this likely extension of the STATS19 system is summarised in Appendix 3. It includes the fact that 12 police forces have been recording such data using a prototype national form since 1999, and gives some examples of the kinds of findings that emerge from trial analyses of the resulting data. Any use of those data will, however, need to bear in mind that they are for a particular set of police forces and that they are not comparable with the nationwide data that are likely to become available from 2006 because the form recommended for use from 2005 is likely to differ appreciably from the previous prototype form.

A separate important source of information about factors contributing to road accidents and the mechanisms by which people are injured in such accidents is the detailed on-the-spot study of particular accidents by multi-disciplinary research teams who are called to the scene of the accident as soon as practical after the accident becomes known.

When they become available, the national contributory factors data will extend the range and reliability of estimation of the incidence of particular contributory factors and thus complement the findings of on-the-spot studies. The new data will, however, in no way replace the data from on-the-spot studies, because the judgement of the reporting officer however valuable and experienced, cannot substitute for in-depth multi-disciplinary investigation.

3.3 The role of research

These and other sources of relevant data provide the foundation for extensive ongoing programmes of research, covering many safety-related aspects of road user behaviour and road and vehicle engineering. Much of this research is commissioned by the DfT, and details of the current programme and the full text of reports resulting from recent years' programmes can be found on the Department's website. Other government departments also commission relevant research. Complementary and independent studies are funded by the Research Councils and independent foundations. Research within Britain is further complemented by cross-national studies funded by the EU, and by systematic exchange of information with researchers in other OECD countries. The scope of current programmes is outlined in Appendix 4.

The road safety strategy is firmly based upon knowledge accumulated from half a century's research of these kinds, and ongoing research continually supports and refreshes the development, implementation and monitoring of the strategy in the light of changing circumstances and understanding.

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