title: Spatial regression analysis of traffic crashes in Seoul.
abstract: Traffic crashes can be spatially correlated events and the analysis of the distribution of traffic crash frequency requires evaluation of parameters that reflect spatial properties and correlation. Typically this spatial aspect of crash data is not used in everyday practice by planning agencies and this contributes to a gap between research and practice. A database of traffic crashes in Seoul, Korea, in 2010 was developed at the traffic analysis zone (TAZ) level with a number of GIS developed spatial variables. Practical spatial models using available software were estimated. The spatial error model was determined to be better than the spatial lag model and an ordinary least squares baseline regression. A geographically weighted regression model provided useful insights about localization of effects. The results found that an increased length of roads with speed limit below 30 km/h and a higher ratio of residents below age of 15 were correlated with lower traffic crash frequency, while a higher ratio of residents who moved to the TAZ, more vehicle-kilometers traveled, and a greater number of access points with speed limit difference between side roads and mainline above 30 km/h all increased the number of traffic crashes. This suggests, for example, that better control or design for merging lower speed roads with higher speed roads is important. A key result is that the length of bus-only center lanes had the largest effect on increasing traffic crashes. This is important as bus-only center lanes with bus stop islands have been increasingly used to improve transit times. Hence the potential negative safety impacts of such systems need to be studied further and mitigated through improved design of pedestrian access to center bus stop islands.
authors.affiliation: Graduate School of Environmental Studies, Seoul National University, Main Campus, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea. Electronic address: lka1974@snu.ac.kr.
authors.forename: Kyoung-Ah
authors.initials: KA
authors.lastname: Rhee
authors.affiliation: Korea Research Institute for Human Settlements, National Infrastructure Research Division, 224 Simin-daero, Dongan-gu, Anyang-si, Gyeonggi-do 14067, Republic of Korea. Electronic address: kimjoonki@krihs.re.kr.
authors.forename: Joon-Ki
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Graduate School of Environmental Studies, Seoul National University, Main Campus, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea. Electronic address: yilee@snu.ac.kr.
authors.forename: Young-ihn
authors.initials: YI
authors.lastname: Lee
authors.affiliation: University of Iceland, Faculty of Civil and Environmental Engineering, Hjardarhagi 2-6, IS-107 Reykjavik, Iceland. Electronic address: gfu@hi.is.
authors.forename: Gudmundur F
authors.initials: GF
authors.lastname: Ulfarsson
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D003710:Demography / Q000706:statistics & numerical data*; D004779:Environment Design / Q000706:statistics & numerical data*; D006801:Humans; D012044:Regression Analysis; D056910:Republic of Korea; D012111:Residence Characteristics / Q000706:statistics & numerical data*; D012449:Safety; D066106:Seoul; D062206:Spatial Analysis
keywords: Policy analysis; Spatial correlation; Spatial data; Spatial econometrics; Traffic analysis zone (TAZ); Transportation planning