Knowledge Resources

This report highlighted several applications of ITS traveler information services used to manage demand during periods of congestion, including congestion during commute periods, special events, and emergencies. The authors defined advanced traveler information systems as technologies that assemble and process travel-related data and disseminate useful information to travelers.

In September 1999, over 500,000 people were evacuated from coastal areas of South Carolina prior to landfall of Hurricane Floyd. During evacuation and re-entry, traffic managers used permanent and portable traffic sensors to monitor traffic flow on several major interstates and roadway facilities. The traffic data collected indicated contraflow (i.e., lane reversal) operations would be required on I-26 during re-entry operations. Traffic and emergency managers quickly deployed dynamic message signs and highway advisory radio on this corridor to facilitate contraflow and ease traffic congestion as evacuees returned home. Traffic counts collected on I-26 showed the potential of what a successful contraflow operation can accomplish. During the return trip, when inbound traffic used both sides of the freeway, maximum per lane volume increased to 2,082 vehicles per hour, a 44 percent improvement over the outbound volumes when I-26 experienced severe congestion. South Carolina DOT and Highway Patrol personnel reported that traffic flow during the re-entry was very smooth.