Mapping intersection accidents with GIS technology in Huntsville, Alabama, U.S.A

This study investigates the influence of intersection accidents that threaten traffic safety, and applies geographic information systems (GIS) to map intersection crashes in Huntsville, Alabama. The DOFE (degree of freedom on entry) approach was used to classify traffic crash events. The event variables and their characteristics are either qualitative (a contributor influence) or quantitative (a causation influence) of intersection crashes. Twenty intersections were set for observations, out of which three were chosen as study sites for 24 months. During the period, DOFE modules (DOFE¹, DOFE², and DOFE³) were used to show traffic influences at the study sites. DOFE¹ was a representative module exhibiting the various traffic characteristics (e.g. turning traffic, traffic speed, signalization, and other factors that develop with traffic). DOFE² represents facility design characteristics and DOFE³ shows the influences of traffic times and seasons. The result showed that intersection traffic needs adequate control of movements at the facility. Data collected from Huntsville Police and other agencies were used for analysis. The study finds that lack of visual attention was the primary cause of Huntsville´s intersection crashes; this includes distracted driving, static and dynamic acuity. Turning traffic was a secondary cause of crashes, followed by signalization. In view of these results, this study recommends an increase in funding maintenance of traffic facilities and the establishment of driver training programs to increase awareness of distracted driving. The DOFE method is not an approach to predict accident frequencies.