Work Zone Mobility and Safety Program

Guidance on Using Traffic Management Centers for Work Zone Management


Each TMC is unique, and therefore the resources available will vary. A number of strategies for using TMC resources most common to all TMCs have been defined in previous sections of this document; however, as detailed in the table below there are many TMC resources available. The resources documented provide an overall view of the capabilities of a TMC.

Table 53. Common Traffic Management Center (TMC) Capability and Data Definitions
Traffic Management Center (TMC) Capability/Data Definition
Archived dynamic message sign messages Historical information about messages posted to dynamic message signs (e.g., timestamp, message text)
Archived environmental sensor data Historical data about weather, air quality, or noise
Archived traffic data Data collected for the highway network in the proximity of the work zone. Data collected continuously, archived, and made available at time intervals of 15 minutes or less. Volume data is required to perform volume-to-capacity calculations. Volume, occupancy, and speed are required to support delay, road user costs, and to predict queues. Data may also consist of vehicle classification and travel time data
Archived video footage Historical footage of video captured by closed-circuit television
Area traffic generators Information describing local venues and relevant schedules known to generate significant amounts of traffic (e.g., schools, stadiums, conference centers)

Note: May include anecdotal information known by TMC operators or a formal list/database of local venues with schedules.
Area transit services Information about area transit providers and their general operations
Centralized Traffic Signal Control The capability to implement traffic signal control timing plans from the TMC for arterial roads in the proximity of the work zone.
Dynamic message sign message logs Recordings of the actual dynamic message sign messages posted to portable and permanent dynamic message signs by the TMC, including a date/time stamp of when the messages where posted
Environmental monitoring and reporting Surveillance of weather, air quality, or noise related aspects of the environment that affect roadways

Note: The operation of environmental monitoring systems may be operated by various groups within the Department of Transportation (DOT). Some agencies incorporate the real-time environmental condition reports in the Road Condition Reporting System. In these situations, the TMC has the capability of environmental monitoring and reporting.
Highway Advisory Radio control Managing the content that is broadcast over Highway Advisory Radio transmitters to deliver en-route information to travelers
Incident management Detection of and response to incidents. Incident detection may include the use of resources such as visual roadway surveillance and traffic data collection. Incident response may include the use of tools such as dynamic message sign control, lane management and control, and ramp meter control
Lane management and control Dynamically managing speeds and lane functions (e.g., high-occupancy vehicle (HOV), reversible lane travel, lane pricing)
Lane management control plans Information about operational conditions and controls used to manage lanes
Locations of communication infrastructure Maps showing agency-owned or leased communication (landline and wireless) for TMC field devices
Locations of evacuation routes Maps and operational plans of designated evacuation routes
Locations of TMC-controlled field devices Maps, geolocations, or text descriptions of field devices controlled or accessed by TMCs. Field devices may include:
  • Detectors (e.g., in-pavement devices or roadside devices)
  • Ramp meters (including roadside signs, controllers, and communications)
  • closed-circuit television cameras (including camera locations and local communications)
  • dynamic message signs (including locations of permanent dynamic message signs and portable dynamic message signs)
  • Highway Advisory Radio broadcast transmitters
  • Managed Lane Devices (e.g., locations where individual lane signing is used to manage travel within lanes)
  • Environmental sensor stations (including descriptions of sensors located at specific sites)
  • Communications infrastructure (including agency-owned or leased communication (landline and wireless) for TMC field devices)
Maintenance dispatch Dispatching agency maintenance forces for roadway clean-ups, snow and ice removal, and other routine maintenance activities

Note: Depending upon the DOT approach, this may or may not be a capability of the TMC. Some agencies dispatch maintenance activities from locations outside the TMC.
Performance measurement and management tools TMC access to tools to assist in analyzing the extent of traffic delays or queue lengths in an around the work zone. Use is either to perform analyses during the work zone (to determine if adjustments are needed) or post-work zone analyses to understand the actual impacts

Note: Also requires access to volume, occupancy, speed data.
Performance measurement reports Historical analyses of traffic and incident data to identify trends in congestion, safety, and other areas of roadway performance
Queue detection Existing or temporary field equipment, access to probe data, or video analytics systems to detect queues on the roadway. Automated queue detection is preferred for real-time reporting to travelers, however manually observed queue reporting is possible
Ramp metering control Managing traffic control signals that regulate the flow of traffic entering a freeway
Ramp metering control plans Information about operational conditions and timing used to manage ramp meters (e.g., times of the day ramp meters operate, a description of the algorithm that determines metering rates, and any demand responsive capabilities)
Real-time traffic data collection and access Data collected for the highway network in the proximity of the work zone and made available to TMC operators as it is collected. Speed, travel time, or occupancy data are most often used to identify slow traffic or operational problems. Travel time data (either measured directly or computed from volume and occupancy data) are required to disseminate work zone travel times to drivers
Real-time traveler information TMC operates or participates in the operation of a system to provide drivers with information about current travel conditions pre-trip (e.g., traveler information website) and en-route (e.g., mobile devices, 511 phone, social media, dynamic message signs, etc.)
Road condition and lane closure reporting Real-time reporting of incidents, roadwork, lane closures, driving conditions, and other capacity limiting events; may include manual entry of events or automated ingest of data from external systems (e.g., law enforcement Computer Aided Dispatch [CAD] systems)

Note: Depending upon the system used, events may only include short- to medium-term events (e.g., the current construction season) or may include future planned lane closures for upcoming years. The TMC is typically only one group that enters events. Other groups (e.g., construction, maintenance) would also enter events. This capability is listed as a TMC capability, as the tool used is often operated from within the TMC.
Road conditions and lane closure reports Planned and real-time information about road work, lane closures, road conditions, unplanned incidents, and planned events

Note: TMC operators typically only enter current conditions or near-term planned events. Depending upon the approach, other sources from within the DOT may or may not enter long-term planned road work.
Service patrol Staff who patrol select roadways to provide motorist assistance and support incident management, typically dispatched from TMC operators
Signalized intersection capabilities Information about operational capabilities at signalized intersections (e.g., coordinated, stand-alone)

Note: DOTs vary in their approach to arterial signal control. Some TMCs include arterial signal control and would typically have this data as a resource within the TMC, while other TMCs do not perform or store information about signal control.
Special event traffic management Surveillance, incident management and traveler information tailored to special events (e.g., sporting events, concerts, rallies)
Temporary height/weight/ width restrictions Information about temporary overdimension restrictions

Note: Temporary overdimension restrictions are conditions commonly reported into road condition reporting tools operated by TMCs. However, the permanent overdimension restrictions are commonly not included. Therefore, there is limited functionality that TMC data can perform in situations where overdimension restrictions are required.
Third-party data Supplemental traffic data procured from a third-party service often based on probe data
TMC incident logs Records of the incidents (crashes, stalled vehicles, overturned loads) detected by or reported to TMC operators, typically with the incident type, location, and a reported date/time and cleared date/time associated to each incident

Note: Logs are not a comprehensive list of crashes or crash reports, but rather those incidents known by TMC operators.
TMC operated lane management systems Systems capable of posting messages to drivers that are specific to each lane (typically through overhead dynamic message signs above each lane) to dynamically manage speeds and lane functions. This may include message that lanes are closed ahead, speeds are reduced, or suggestions to merge to other lanes
TMC Staff Time Time that TMC staff can dedicate to coordinating work zone activities, participating in work zone planning meetings and discussions. TMC staff possess knowledge about the traffic patterns and likely impacts of capacity reduction
Traffic data collection Real-time collection of traffic data, typically volume, occupancy, and speed; may include vehicle classification
Traffic signal timing plans Information about operational timing in place at signalized intersections

Note: Some TMCs include arterial signal control and would typically have this data as a resource within the TMC, while other TMCs do not perform or store information about signal control.
Travel time calculation Determining travel times for stretches of highway based on real-time traffic data collection and surveillance
Variable (advisory) speed limit posting Displaying enforceable variable speed limits (or advisory speeds) to drivers based on current traffic or road conditions and/or queues ahead
Visual roadway surveillance (TMC operators and traveling public) Real-time monitoring of the roadway conditions using full motion or still cameras. For the traveling public, access to camera video or images are typically available through traveler information websites. For transportation management, this typically includes access to and control of the pan/tilt/zoom positioning of the cameras to observe stopped or stalled vehicles, incidents, queue lengths, overall traffic flow, or other conditions that could influence real-time management of work zones
Visualization mapping tool for interagency road work and/or lane closures A tool and approach of entering planned road work, together with adjacent agencies entering planned roadwork for the primary purpose of visualizing potential conflicts and/or overlapping road work activities
Volume-to-Capacity Calculation Tool or Process A mechanism to perform volume-to-capacity calculations. Mechanisms range from simple processes (e.g., calculations by hand or using a spreadsheet) to complex (e.g., using a self-developed tool or a procured tool that may include graphics and extensive calculations)

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