自動速度制御装置による制限速度遵守が対自転車の出会い頭事故発生の低減に与える効果

抄録

Approximately half of all traffic fatalities involve pedestrians and cyclists, and exceeding the speed limit is one of the most serious factors causing fatal accidents. The use of an Intelligent Speed Assistance system (ISA) is being considered to reduce the number of traffic accidents caused by exceeding the speed limit. ISAs indicate the speed limit information to drivers or perform a control intervention to avoid exceeding the speed limit. The purpose of this study was to investigate the effects of compliance with the speed limit on reducing the number of vehicle-cyclist collisions, by using a near-miss incident database. This study sought to estimate the effects of an ISA, which provides control interventions to ensure that travel speeds do not exceed the speed limit. In the database, we extracted near-miss incident data that cyclists initiated a road-crossing from blind intersections with speed limits of 30 km/h (i.e., 956 cases), and defined a safety margin as the axis of the effect of accident prevention. Subsequently, the effect of compliance with the speed limit by the ISA on ensuring the safety margin under hazardous events caused by exceeding the speed limit was analyzed. The limitations of the effect of compliance with the speed limit by the ISA were also assessed. The data analysis revealed the following. Of the 956 cases, 129 cases (13 %) showed insufficient safety margins due to exceeding the speed limit. The frequency with which the use of the ISA can be effective in ensuring safety was not high. However, of the 129 cases, 100 cases (78 %) showed that the use of the ISA led to an adequate safety margin; the use of the ISA increased the time available for accident prevention by an average of 0.74 s. The results of this data analysis can contribute to the discussion on the social implementation of ISAs.