Remote sensors, commercial traffic reporters, field units, and individual travelers all combine to provide the information necessary to assess real-time traffic flow. CHART traffic monitoring tools include:
- Traffic speed detectors deployed along 155 centerline miles of the heaviest traveled freeways. These detectors provide the average speed of traffic flow along a segment of roadway. This information is used for early detection of traffic congestion and incidents.
- Existing in-pavement loop detection traffic counting devices which are being retrofitted to provide speed information.
- Video verification is provided by Closed Circuit Television (CCTV) cameras which provide visual information on traffic congestion, incidents and roadway conditions during inclement weather.
- A #77 cellular call-in system by which individual motorists can report disabled vehicles and accidents. This service, coordinated through the MSP and MdTA Traffic Management and Police Services, receives more than 10,000 calls annually.
- Reports from field units including State and local police as well as SHA's own units, and information from commercial radio traffic spotters who operate from aerial as well as ground units.
- Pavement weather sensors installed and operating at locations statewide. These sensors are placed at locations that are the first sites to freeze during winter conditions. They provide pavement temperature, moisture, and degree of chemical treatment during winter operations.