Lakewood Traffic Collisions

In 1999, City of Lakewood GIS staff began digitizing reported traffic collisions using data provided by the Lakewood Sheriff’s Department. Along with the location of each collision, information such as the time and day, alcohol and drug influence, lighting conditions, and other factors related to the collision was captured. More than 10,000 collisions since 1997 have been digitized.

The original purpose of this map was to showcase the collision data created by—and stored in—the city’s GIS. However, after viewing early versions of the map, city government staff began to wonder where the “Top 5” intersections for traffic collisions were and how the collisions were distributed within them. To find the answer, all major intersections in Lakewood were identified. From the center of each intersection, four 100-foot ringed buffers were created in succession starting from the center of each major intersection. Using these buffers, the total number of collisions occurring within 400 feet of each intersection could be determined. This technique provided Lakewood with a Top 5 list as well as the ability to measure the density of collisions in each intersection at regular intervals.

Courtesy of the City of Lakewood, California. Basemap copyright Rand McNally & Co.