The Illinois Department of Transportation (IDOT) uses an Expected Accident Frequency (EAF) formula as one of the parameters in prioritizing the rail-highway grade crossings that need warning devices upgrade. This study evaluated the effectiveness of the formula and assessed the current 0.02 threshold. Field data were collected from three railroad corridors and 93 crossings in Illinois. Four potential models (Connecticut, Michigan, California, and USDOT models) were evaluated using Illinois data and none of them consistently outperformed the IDOT EAF formula. A new Illinois Hazard Index (IHI) formula was developed. The variables used in IHI are average daily traffic, number of trains per day, maximum timetable speed, number of tracks, number of highway lanes, 5-year history, and control devices factor. The IHI formula identified a higher number of locations with a higher crash rate than the IDOT formula did. The revised IHI should be used in combination with other criteria to identify those crossings in need of safety improvement.
|ITRC FR 98-2