PURPOSE: To determine the trends with fatally or otherwise injured pedestrians lying on the road and the relationship to hit-and-run incidents in Japan. METHODS: We extracted data for 2012-2016 from the records of the Institute for Traffic Accident Research and Data Analysis, Japan, a nationwide traffic accident database. All the injured and fatally injured pedestrians were selected. We examined the levels of pedestrian injury, vehicle speed immediately before the collision, whether or not the pedestrian was lying on the road, and hit-and-run incidents. Chi-square test was employed to make a statistical comparison between the two groups. RESULTS: The database contained data on 286,383 pedestrian casualties and 7256 fatalities; 8.3% of fatalities (602 persons) and 0.6% of casualties (1827 persons) involved pedestrians lying on the road. The rates of fatalities and severe injuries were significantly higher for pedestrians who were lying on the road than for those who were not. Hit-and-run incidents were evident in 4.0% of casualties and 7.3% of fatalities. The rate of hit-and-run cases was also significantly higher among pedestrians who were lying on the road. Among fatally injured pedestrians not lying on the road, the rates with speeds of ≥30 km/h did not differ significantly between hit-and-run and other cases. However, when the pedestrians were lying on the road, the rate was significantly increased in hit-and-run cases. CONCLUSION This is the first report to focus on pedestrians lying on the road and being involved in hit-and-run incidents. In addition to preventing hit-and-run incidents, prevention of pedestrians lying on the road could also decrease fatalities.

PURPOSE: Lengthy hospitalization places a burden on patients and healthcare resources. However, the factors affecting the length of hospital stay (LHoS) and length of emergency room stay (LERS) in non-fatal bicycle accidents are currently unclear. We investigated these factors to inform efforts to minimize hospitalization. METHODS: We performed a retrospective analysis of data from non-fatal injured bicyclists admitted to the Emergency and Critical Care Center at Kyoto Medical Center between January 2012 and December 2016. We measured LHoS, LERS, mechanism of injury, head injury prevalence, polytrauma, operations performed, injury severity score (ISS), abbreviated injury scale (AIS) score, maximum AIS score, and trauma and injury severity score probability of survival. We conducted multiple regression analysis to determine predictors of LHoS and LERS. RESULTS: Within the study period, 82 victims met the inclusion and exclusion criteria and were included. Mean age was (46.0 ± 24.7) years. Overall mean LHoS was (16.8 ± 25.2) days, mean LERS was (10.6 ± 14.7) days, median ISS was 9 (interquartile range (IQR): 3-16), median maximum AIS was 3 (IQR: 1-4), and median trauma and injury severity score probability of survival was 98.0% (IQR: 95.5%-99.6%). Age, maximum AIS, ISS, and prevalence of surgery were significantly greater in long LHoS and LERS group compared with short LHoS and LERS group (p < 0.05). Performance of surgery independently explained LHoS (p = 0.0003) and ISS independently explained LERS (p = 0.0009). CONCLUSION Surgery was associated with long hospital stays and ISS was associated with long emergency room stays. To improve the quality life of the bicyclists, preventive measures for reducing injury severity or avoiding injuries needing operation are required.