L-function과 KDE를 이용한 서울시 보행교통사고 잦은 곳의 공간적 범위 설정과 특성 분석

초록

This study aimed to undertake a comprehensive spatial analysis to delineate optimal spatial ranges for identifying frequent pedestrian crash locations. The analysis focused on pedestrian crashes that occurred within the seoul metropolitan government area between 2016 and 2022, selected due to its significantly high ratio of pedestrian fatalities compared to overall traffic accident fatalities among metropolitan jurisdictions. To investigate the spatial dependence among point patterns of pedestrian crash data, ripley's k-function and l-function were employed to analyze the degree of clustering by distance. The findings indicate that pedestrian crashes each year exhibited clustered patterns characterized by spatial dependence among individual crash points, with clustering evident within distances of 30.7 meters as indicated by the rate of increases in l-function values, gradually tapering off beyond this range. Furthermore, a similar analysis conducted on non-pedestrian crashes revealed clustering within distances of 35.7 meters, approximately 1.16 times the observed clustering range for pedestrian crashes. Based on the application of l-function selected results, which identified pedestrian crash hot spots, and reviewing the kernel density estimation within 5 meter increments up to a 50 meter radius, the total count of hot spots shows a gradual increase, with less than 10% within buffer radius of 30 to 35 meters. Beyond this distance, the rate of increase diminishes more steeply. Moreover, the results indicate that expanding the buffer radius includes accidents on adjacent roads. Therefore, selecting a minimum distance of 30 meters for hot-spot analysis is meaningful. Spatial analysis of pedestrian crash hot spots based on intersection, road width, and land use metrics revealed higher proportions of hot spots along secondary and tertiary roads compared to main arteries, with higher risk associated with unsignalized roads than signalized intersections. This underscores the necessity for ongoing pedestrian safety policies targeting residential roadways.

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