Finding the best indicators to be added in RSDI

The first step in designing a road safety development index (RSDI) is to come up with a comprehensive set of indicators, which includes as far as possible aU the main parameters in road safely of human-vehicle-road-enviromnent-regulation, instead of considering a few factors such as accident rates per population or per kilometoe driven. In addition, this index should be as relevant as possible for different countries, especially in developing countries. The choice of accident risk and exposure variables is necessary to what is available in international data and what is considered necessary for meaningfiil comparisons. Commonly, frequencies of aimual numbers of vehicles, accidents, injured and killed people are some kind quantification and relatively easy to define and to measure in different countries. But differences in definitions, noncollection of data, non-rehabUity of data and under-reporting are problems for effective measurements of road safety. 

It is not possible to gather all sets of macro-indicators that are shown in Table 3.2 into the RSDI index, not only because they are many and they will take too much time to interpret and analyse, but because some of the indicators are requiring further development, which means availability and definitions. The number and type of indicators depend on the development level of a country, motorisation level (vehicles per population), and availability of data. The response of any indicator varies from one country to another. For instance, one acceptable indicator is deaths per vehicle kilometre and it is an important element to be added to RSDI, but this measure is still not available in most developing countries. Hence this indicator is excluded from the selected indicators in the current study. For a similar argument, the indicator percentage of motorways per road network was dropped because it has a low quality and reliability of data and there is a difference of definition of road standards across the countries. In fact, there are several indicators that may play an essential role in the development of RSDI, but unfortunately it is hard to obtain at this stage and they will be kept for further and future development. The selection of set of core indicators for RSDI is not final. The indicators will continue to be developed and refined. 

In principle, eight general themes have been selected in the construction of RSDI, which are traffic risk, personal risk, vehicle safety, roads situation, road user behaviour, socio- 

The first chosen dimension is the level of traffic risk in a country, which deals with the fatalities rates. The fatality rate per vehicle is currently used, while fatality rate per vehicle-km or per person-km or per type of road user (pedestrians, cyclists, motorcyclists and drivers) are all other indicators of this dimension and they can be used on the long term of RSDI. 

The second dimension is the personal risk, which is defined as fatahties per total population. An additional indicator that might be added in the long term is the fatahties per age of population. 

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