Report numberRA-MOW-2011-026
TitleThe effect of an ageing society on road safety
SubtitleA projection of the number of fatalities and seriously injured persons in 2030
AuthorsKurt Van Hout
Tom Brijs
Published byPolicy Research Centre for Mobility and Public Works, track Traffic Safety 2007-2011
Number of pages88
Document languageDutch
Partner(s)Universiteit Hasselt
Work packageOther: Risk assessment

Society evolves constantly. Most western countries are today confronted with a sharp increase of the number of older inhabitants. At the same time the number of 25-40-year-old decreases. Furthermore this demographic trend is accompanied by some other societal developments, as an increasing level of activity and drivers’ license ownership. These evolutions will undoubtedly influence the total exposure of the different groups that make out the population. The number of traffic victims will alter accordingly.


In this study the number of deadly and seriously injured traffic victims is calculated as the product of exposure and the risk of getting injured seriously. This is done on a disaggregated level as to detect shifts between different subgroups in the population or between modes. The subgroups are determined by age and gender and exposure (the distance travelled) is calculated for the different modes of transportation, in this study confined to 4: car driver, car passenger, pedestrian and cyclist.


Exposure depends on the size of each group and on the average distance travelled by each mode of the members of the group. The population projections take into account demographic evolutions, changes in the level of activity and the increasing ownership of drivers’ licenses. The first 2 are taken from existing projections. Drivers’ license ownership is modeled based on the Flemish travel survey data (that were collected in the period 1994-2010), as is the average distance travelled.


The distance travelled is calculated at the individual level. As a consequence of socio-demographic changes this will reflect in the exposure on population level. For all 4 studied transport modes the total distance travelled will increase. The increase is however not equal for the different population groups. 3 scenarios are built in which the 3 socio-demographic changes are added one at a time. This enables us to determine the influence of the different socio-demographic drivers on exposure separately. The scenarios are called DEMO (only demographic changes), SOCIO (additional changes in work status) and RB (additional changes in drivers’ license ownership). This last RB-scenario is considered the most complete and best representing the expected reality.


Deze worden in dit rapport het DEMO-scenario (enkel demografische wijzigingen), SOCIO-scenario (bijkomend aanpassingen in werkstatus) en RB-scenario (bijkomende aanpassingen van rijbewijsbezit) genoemd. Het RB-scenario is hierbij het meest volledige dat het best aansluit bij de verwachte realiteit.


The second component in the analysis of injury risk, or the probability a person gets seriously injured in a crash. From earlier studies we know that risk isn’t equal for all road users. It also evolves differently for different population groups and modes. In this study the trends from the past are extrapolated to the future. This is done again for the same subgroups and modes.


The projection of the number of fatally and seriously injured is split up into 4 steps in order to expose the influence of the separate trends concerning demography, activity level, drivers’ license ownership and injury risk.
When the risk is held constant at the level of 2001, we find, due to the higher exposure, an increased number of fatally and seriously injured crash victims in the future. However, the increase differs among different age groups. From 45 year on the number of victims increases, the most distinctly in the age groups 55-64 and 75+. The share of older people as crash victims will therefore increase in the future. The share of men older than 65 will increase from 13,2% in 2001 to 19,3% in 2020. With women the share will increase from 17,0% to 22,7%. S


plit up according to mode we find the number of car victims increasing less then global exposure as car occupant. Concerning cyclists and pedestrians we find the opposite: the number of victims increases more than their exposure. The relative shares of the 4 modes remain nevertheless fairly constant.


When we take into account however the decreasing trends of the injury risk for the subgroups and modes, we find a substantial decrease of the number of crash victims. In 2020 the global number of killed and seriously injured car occupants, cyclists and pedestrians decreased with almost 60% compared to 2001. Again the decrease isn’t equal for all subgroups. In the groups of women younger than 45 the number of victims decreases with more than 70%. Males older than 55 show a less marked decrease (40% lower in 2020 compared to 2001). The number of female victims older than 75 decreases even less (only 7,5% less). The share of older people in the crash statistics will therefore increase. In 2020 19% of the male victims will be older then 65 (in 2001 the share was around 13%). Female victims will rise to a share of 36% in 2020 compared to 19% in 2001.


We also find different evolutions for the different modes. In the group of car occupants we find a sharp decrease in the number of fatalities and seriously injured, caused by the favorable evolution of the injury risk (-76% for car drivers and -64% for car passengers). The evolution in the group of cyclists and pedestrians is far less advantageous. In 2020 we expect the number of injured cyclist to be 23% lower than in 2001. The decrease in the group of pedestrians is estimated at 13%. Therefore the share of victims will, under these assumptions, shift towards the vulnerable road users.


The analyses show a number of groups with a less favorable evolution of the number of fatally and seriously injured crash victims, like people older than 55 (especially females older then 75) and the vulnerable road users. Specific road safety measures are therefore needed to reduce faster the risks these groups face.

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The Policy Research Centre for Traffic Safety carries out policy relevant scientific research under the authority of the Flemish Government. The Centre is the result of a

cooperation between Hasselt University, KU Leuven and VITO, the Flemish Institute for Technological Research.


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