U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
REPORT |
This report is an archived publication and may contain dated technical, contact, and link information |
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Publication Number: FHWA-HRT-12-054 Date: December 2012 |
Publication Number: FHWA-HRT-12-054 Date: December 2012 |
The goals and initiatives established by agencies determine the TMC functions and the measures that evaluate these functions. Appendix A provides one agency's flow sequence for this process.
Table 1 identifies many of the possible functions of TMCs by the types of facilities managed. In later sections of this report, these functions are related to performance measures and the data and parameters needed to implement those measures.
Performance evaluation systems may take either of the following forms:
Performance evaluation systems may include the archived data user service functions of the National ITS Architecture.(2)
Table 2 provides key functional characteristics for several performance evaluation systems.
Table 1. TMC functions.
TMC Functions | Facilities Managed by TMC | Comments | |||
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Freeways | Signal Systems and Surface Streets | Corridorsa | Special Facilitiesb | ||
Active Traffic Managementc | X | X | X | See reference 3. | |
Speed harmonization | X | X | |||
Temporary shoulder use | X | X | |||
Queue warning | X | X | |||
Dynamic truck restrictions | X | X | |||
Dynamic routing | X | X | X | ||
Dynamic lane markings | X | X | |||
Data Analysis and Warehousing | X | X | X | X | These are support functions. They relate to outputs rather than to outcomes. No measures are provided for these functions in section 3. |
Incident Response | |||||
Development of incident management plans | X | X | X | X | |
Selection of incident management plan | X | Where TMCs have this responsibility | X | X | |
Assistance to emergency service providers | X | X | X | ||
Maintenance | These are support functions. They relate to outputs rather than to outcomes. No measures are provided for these functions in section 3. | ||||
Maintenance of TMC facilities | X | X | X | X | |
Management of field equipment maintenance | X | X | X | Field equipment maintenance management for corridors depends on division of responsibilities. | |
Configuration management of TMC and ITS facilities | X | X | X | X | |
Coordination of roadway maintenance and construction | X | X | X | ||
Motorist Information | |||||
Management of information for ITS field devices | X | Where agency operates devices | X | X | |
Provision of information to external services | Sometimes | ||||
Planning | X | X | X | X | These are support functions. They relate to outputs rather than to outcomes. No measures are provided for these functions in section 3. |
Ramp Management and Conventional Lane Management | |||||
Ramp metering | X | X | X | ||
Ramp closure | X | X | X | ||
Conventional lane controls | X | X | X | X | |
Security | These are support functions. They relate to outputs rather than to outcomes. No measures are provided for these functions in section 3. | ||||
Security in TMC | X | X | X | X | |
Security of ITS field devices | Possibly | Not often | Possibly | Usually | |
Other security functions | Possibly | Not often | Possibly | Usually | Security monitoring of other transportation department facilities. |
Service Patrol | X | X | |||
Signal Timing | |||||
Signal timing plan development | X | Seed | |||
Signal timing operations management | X | Seed | |||
Emergency vehicle signal preemption | X | Seed | |||
Special Functions | These are support functions. They relate to outputs rather than to outcomes. No measures are provided for these functions in section 3. | ||||
Roadway ventilation | X | See reference 4. | |||
Roadway fire detection and suppression | X | See reference 4. | |||
Other Supervisory Control and Data Acquisition Functions | X | May include pumping, electrical system control, and motorist telephone system.(4) | |||
Training and Support | X | X | X | X | These are support functions. They relate to outputs rather than to outcomes. No measures are provided for these functions in section 3. |
Transit Assists | |||||
High occupancy vehicle (HOV) bypass of metered lanes | X | X | X | ||
Transit signal priority | X | Seed | |||
Weather Monitoring | X | Not usually | X | X |
a Includes TMCs with responsibility for operations on alternate routes.
b Includes bridges and tunnels.
c Active traffic management includes speed harmonization, temporary shoulder use, queue warning, dynamic merge control, construction site management (active traffic management methodologies), dynamic truck restrictions, dynamic routing and traveler information, and dynamic lane markings. Separate lines will be provided for each strategy.
d Responsibility for timing plan development and operations rests
with the agency responsible for traffic signal systems. This function is
applicable when freeway and signal system TMCs share a common facility.
Note: Blank cells in the comments field indicates no comment was provided.
Table 2. Characteristics of representative ITS performance evaluation systems.
System | Key Data Processing Features | Data Collection Periods | Data Source | Key Measures Provided |
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California Department of Transportation (Caltrans) Freeway Performance Measurement System (PeMS)(5,6) |
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Collects data at 30-s intervals, then aggregates to 5-min and hourly periods. |
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Volume, occupancy, speed, congestion delay, vehicle miles traveled (VMT), and travel times. |
Washington State Traffic Data Acquisition and Distribution System |
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Collects data at 20-s intervals, then aggregates to 5-min data. |
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Volume, occupancy, speed, travel time, and travel time reliability. |
Minnesota TMC(7) |
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Collects data at 20-s intervals, then aggregates to 5-min data. |
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Florida Statewide Traffic Engineering Warehouse for Regional Traffic Data (STEWARD); designed as a statewide system that links to each district(8) |
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Collects data at 20-s intervals, aggregates to 5-, 15-, and 60-min periods. |
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Volume, occupancy speed, lane volume balance, effective vehicle length (see section 5.1.2.1), input/output balance, VMT, vehicle hours, delay, kinetic energy, and level of service. |
a Additional information is provided in table 22.
b The g factor represents the effective length of the vehicle at the tuning of the loop detector. It
varies over the course of time. An algorithm is in PeMS to calculate the g factor as a function of time.
Note: Blank cell indicates no key measures were provided.