Section 4 Is the rise in participation trend for elderly drivers the result of the increase in the number of license holders?
  To eliminate the effects of increase or decrease in the number of driver's license holders to allow for comparison between age groups, "accident frequency rate" is defined as:

  Accident frequency rate = 1000 × number of participants / number of driver's license holders of appropriate age group (per 1000)

  Accident frequency rate by age group, both indexed and non-indexed, is used in the following paragraphs.

  According to the accident frequency rates in Fig. 8, drivers under 25 years old are two times more likely to be involved in an accident compared to other age groups. It can also be seen that the accident frequency rate of the elderly is comparatively low. As will be touched on later, this reflects the relatively shorter distance traveled by elderly drivers.

Fig. 8 Accident frequency rate by age group
  The accident frequency rates in Fig. 9 show an increase across all age groups. This means that the number of drivers participating in accidents is increasing at a rate that surpasses the increase in driver's license holders. Among the age groups, 35-44 and 25-34 stand out. As there is a considerable difference between the age groups, the increase cannot be attributed only to deterioration in traffic environment conditions. A simple inference can be made that certain age groups are more prone to causing accidents, or, that the opportunity to drive has increased for those groups.

Fig. 9 Trends in accident frequency rate by age group (indexed)
  [Reference: Bicycle riders]
  As bicycle use does not require a license, the accident frequency rate for this category was based on participants in a population of 1,000 instead.

  As shown in Fig. 10, the accident frequency rate for bicycle users 24 years and younger is extremely high, probably because bicycling is a major means of transportation for this age group (as many don't have a driver's license), in addition to this transportation mode being action-oriented.

Fig. 10 Accident frequency rate by age group while on bicycle
  In the index trends of Fig. 11, the accident frequency rate for both the 25-34 and 35-44 age groups rose considerably, resulting in values about 1.8 times greater in 2005 compared to the base value (1996). The 24 and younger group reached 1.5 in 2005 as well. The 75 and older group showed the lowest rate of increase among the other age groups, with a gain of only about 1.1 times the base value.

Fig 11 Trends in accident frequency rate by age group (indexed) while on bicycle
  [Reference: Pedestrians]
According to the accident frequency rates in Fig. 12 and the accident frequency index in Fig. 13, while the rate for the elderly age group is declining, the rate for the 25-34 and 35-44 groups is increasing. This seems to point out that the elderly are shifting from walking to driving. However, as shown in Fig. 12, the accident frequency rate for elderly pedestrians is still very high, nearly 2 times greater than that of the comparatively younger groups.

Fig. 12 Accident frequency rate by age group when walking

Fig. 13 Trends in accident frequency rate by age group (indexed) when walking

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Institute for Traffic Accident Research and Data Analysis (ITARDA)