Dynamic Traffic Alerts Issued to Commercial Motor Vehicles in North Carolina Showed a 70 Percent Compliance Rate and Reduced Speeds by up to 11 MPH.

To manage congestion from incidents like crashes and work zone delays, the North Carolina Department of Transportation (NCDOT) has used about 300 Dynamic Message Signs (DMS) controlled by a central traffic management center. However, these signs leave many areas uncovered, creating gaps in real-time traffic communication. Additionally, drivers could seek information via a website or 511 phone system. In response to these challenges and the 15,557 commercial motor vehicle crashes in 2021, NCDOT partnered with a probe data company and an in-cab communication company to implement a real-time in-truck alert system. Launched in 2021, this innovative system utilized probe speed data and in-cab communications via Electronic Logging Devices (ELD) to deliver instant alerts about slowdowns and congestion directly to truck drivers. NCDOT began this alert system with 500 miles of rural Interstates, initially covering I-95 and rural parts of I-40, with I-77 added in late 2021. In 2022, the service expanded to nearly all freeways in the state, covering 2,200 miles.