Transportation Injury Mapping System_Los Angeles Countywide Collisions_2014_2024

The Transportation Injury Mapping System (TIMS) collision dataset was downloaded on 8/3/2026 for all collisions that occurred within Los Angeles County in the years 2014-2024, inclusive. The dataset contained 570,269 recorded collisions. There are two sets of coordinate fields in the TIMS schema: longitude and latitude (Lat/Long), and point_x and point_y (X/Y). The coordinate data was found to have four presentations at this point, where: only the Lat/Long is populated, only the X/Y is populated, both sets of coordinate data are populated, or neither set is populated. There were 13,053 records in that last presentation, with neither populated. These records were excluded from the dataset on the basis of this data being provided for spatial analysis. Using the 557,216 records with spatial information included, the data was mapped using PostGIS functionality, then brought into ArcGIS Pro. A copy of that dataset was then made into a Feature Class for ease of loading and editing. To address clearly incorrect collision locations, the 1,071 data points that fall outside of the county boundary were removed as well, bringing the collision point total to 556,145. A total of 14,124 records, amounting to 2.48% of the original dataset, were omitted for the reasons stated above. The fields ‘Join_Count’, ‘target_fid’, ‘join_fid’, ‘city_comm_name’ and ‘jurisdiction’ are the product of a spatial join with a polygon layer of the cities and unincorporated neighborhoods. (‘county’ and ‘city’ are from the original TIMS dataset). This spatial join was performed by Los Angeles County's Internal Services Department in order to help to distinguish unincorporated neighborhoods and also validate the record's location. This spatial join used the one-to-many setting, which creates duplicate records (in this case collisions) for any record that touches two polygons. There were 17 such collisions that fell exactly on the boundary between two areas, and therefore a duplicate was created for each. A value of ‘2’ in the field 'Join_Count' will reveal these duplicated collisions. This data is projected in California State Plane V (WKID 2229). Credit: Transportation Injury Mapping System (TIMS), Safe Transportation Research and Education Center, University of California, Berkeley. 2026本交通伤害映射系统（Transportation Injury Mapping System，TIMS）碰撞数据集于2026年8月3日完成下载，涵盖2014年至2024年（含首尾年份）洛杉矶县境内发生的全部道路碰撞事故，共计收录570269条已记录的事故数据。TIMS数据模式中包含两类坐标字段：经纬度（Lat/Long）与平面直角坐标（point_x、point_y，即X/Y坐标）。经核查，该数据集的坐标数据存在四种呈现形式：仅填充经纬度字段、仅填充平面直角坐标字段、两类坐标均已填充，或两类坐标均未填充。其中最后一类（两类坐标均未填充）共涉及13053条记录，因本数据集用于空间分析，此类缺失有效空间信息的记录已被全部剔除。基于包含有效空间信息的557216条记录，研究人员通过PostGIS功能完成空间数据映射，随后将处理后的数据导入ArcGIS Pro。为简化后续加载与编辑流程，该数据集的副本被转换为要素类（Feature Class）。为修正明显存在错误的碰撞事故位置信息，1071个落在洛杉矶县界外的数据点也被移除，最终有效碰撞点总数调整为556145个。综上，本次共剔除14124条原始记录，占原始数据集总规模的2.48%。字段"Join_Count"、"target_fid"、"join_fid"、"city_comm_name"及"jurisdiction"为与城市及非合并社区多边形图层开展空间连接后的衍生字段（原始TIMS数据集仅包含"county"与"city"两个基础字段）。此次空间连接由洛杉矶县内部服务部执行，旨在区分非合并社区并验证记录的空间位置准确性。本次空间连接采用一对多模式：当一条记录同时触碰两个多边形区域时，系统将为其生成重复的事故记录。本次共有17起碰撞事故恰好落在两个区域的边界线上，因此为每条此类事故生成了重复记录，字段"Join_Count"的取值为"2"时，即可识别此类重复碰撞事故。本数据集采用加利福尼亚州平面坐标系第五区（WKID 2229）进行投影。数据来源：加州大学伯克利分校安全交通研究与教育中心交通伤害映射系统（TIMS），2026年。