This paper presents results of a benefit/cost analysis of the rural call box system installed by the Georgia Department of Transportation along 39-miles of Interstate 185. The system included 147 call boxes spaced approximately 1/2 mile apart along both sides of the highway. Calls placed from the boxes used cellular technology to contact the appropriate 911call center directly. Traffic volumes on the interstate were low, with an average annual daily traffic ranging from 13,000 to 67,400 along various segments.

Travelers using the call boxes during the first six months of operation reported 920 incidents. To compute the benefit/cost ratio for the call box system, costs were derived from contract costs for maintenance and cellular service and a 10-year amortization of the capital and installation costs for the system. This resulted in a cost for the six-month period of the study of $119,639.87.

Benefits of the call boxes were computed based on the assumed number of injuries and fatalities eliminated and by assigning assumed monetary benefit values to the actual calls received from the call boxes. The study assumed that the call boxes would eliminate one injury per year and one fatality every five years. Using FHWA’s 1998 Technical Advisory on Motor Vehicle Accident Costs, the fatality cost of $2.6 million and the injury cost of $59,000 lead to a benefit of $289,000 over the six-month investigation due to the reduced number of injuries and fatalities. The following table presents the dollar values assigned to the various types of calls received from the call boxes.

Source: Kolb, et al.

Applying these values to the call box calls yields an additional benefit of $40,320. Combined with the benefits from avoided injuries and fatalities the total benefit of the call box system becomes $329,820. This yields a benefit-to-cost ratio of 2.76.