3 Accident-Reducing Effect of Measures Program
  We compared annual number of accidents before and after measures, regarding the 1,665 locations nationwide where measures had been implemented between 1996 and 1999. The number of casualties at the locations where measures had been implemented dropped by approximately 7% over the period prior to the implementation of measures (Table 2).

Table 2  Comparison of Annual Number of Casualties at Locations Where Measures Were Implemented

  Several years passed from the time specific accident-prone locations were selected until the measures program was completed, and during that time the number of accidents nationwide increased. The number of accidents on all main arteries went up approximately 33% by 2000. When this is taken into consideration, the implementation of measures reduced traffic accidents by approximately 30% (Figure 2).

Figure 2  Effects of Measures Program on Accident-Prone Locations

  We compared the number of accidents before and after measures, classified according to type of accident, at locations where measures had been implemented by 1999. The results are shown in Figure 3. Although the total number of accidents at all locations decreased, some types of accidents, namely, "rear-end collisions" and "collisions while turning left," increased. Even though the rate of such accidents is below that of total accidents at main arteries, the increase in rear-end collisions pulled up the rate of increase for the total number of accidents because rear-end collisions occupy a large proportion of all accidents.
  We believe that the measures made a significant contribution to reducing the number of person-to-vehicle accidents, head-on collisions, collisions with structures, and other types of accidents that are likely to cause fatalities, as well as the number of serious accidents.

Figure 3  Comparison of Number of Accidents Before and After Measures, Classified by Type of Accident

  If we look at the year-to-year change in the number of accidents only at the specific locations, there could be random fluctuations; and if we limit our view to fatalities, then tendencies over the short term are particularly hard to grasp. In order to evaluate the short-term impact of measures on reducing fatalities, therefore, we compared fatality rates before and after measures, using the following definition for "fatality index" (Table 3).

Table 3 Comparison of Effects of Measures by Annual Fatality Index

  The fatality index indicates to what extent the number of casualties is equivalent to the number of fatalities, and the more types of accidents with high fatalities there are, the greater the index will be. The fatality index at specific accident-prone locations drops from 197 before measures to 122 after measures, approximately a 38% drop. Since this is larger than the overall rate of decrease in the number of casualties (6.8%), it is evident that measures have a stronger effect on the types of accidents that are likely to cause fatalities.
UP

Institute for Traffic Accident Research and Data Analysis (ITARDA)