The Georgia DOT Intelligent Transportation System, known as NaviGAtor, covers 140 freeway miles in the Atlanta metropolitan area. The NaviGAtor system includes a traffic management center (TMC), freeway management components, advanced traveler information systems, and an incident management program. TMC operators use vehicle detectors, closed circuit television (CCTV) cameras, dynamic message signs (DMS), and ramp meters to collect traffic data and manage incidents. When TMC operators identify an incident, they dispatch a Highway Emergency Response Operator (HERO) to provide motorist assistance or traffic control, and disseminate traveler information via DMS, the NaviGAtor web site (www.georgia-navigator.com), and a telephone information service (*DOT or 404-635-8000).
The benefits of the NaviGAtor incident management program were determined during a before-and-after study that analyzed twelve months of data (i.e., May 2003 to April 2004) from incident logs. The "before" conditions were estimated by analyzing incident information when a HERO could not respond, analyzing incidents that occurred outside of the NaviGAtor coverage area, and using public safety dispatch logs and personnel surveys to predict incident timelines when no NaviGAtor resources were employed. By comparing "before" conditions with "after" conditions when NaviGAtor incident management strategies were utilized, the benefits were determined in four areas: safety, mobility, energy and environment, and productivity.
The benefits above and the value of HERO motorist assistance resulted in a cost savings of more than 187 million dollars, which was used to calculate a benefit-to-cost ratio of 4.4:1. These productivity benefits are summarized in the table below.
Cost Savings due to NaviGAtor Incident Management Program
Secondary Crash Reduction
Incident Delay Reduction
Fuel Consumption Reduction
CO Emissions Reduction
HC Emissions Reduction
NOx Emissions Reduction
Assistance to Travelers
Total Cost Savings