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
- 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
- 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.