< < TM02 : TM03 : TM04 > >

TM03: Traffic Signal Control

This service package provides the central control and monitoring equipment, communication links, and the signal control equipment that support traffic control at signalized intersections. A range of traffic signal control systems are represented by this service package ranging from fixed-schedule control systems to fully traffic responsive systems that dynamically adjust control plans and strategies based on current traffic conditions and priority requests. This service package is generally an intra-jurisdictional package. Systems that achieve coordination across jurisdictions by using a common time base or other strategies that do not require real time coordination would also be represented by this package. Coordination of traffic signal systems using real-time communications is covered in the TM07-Regional Traffic Management service package. This service package is consistent with typical traffic signal control systems.

Relevant Regions: Australia, Canada, European Union, and United States

Enterprise

Development Stage Roles and Relationships

Installation Stage Roles and Relationships

Operations Stage Roles and Relationships
(hide)

Source Destination Role/Relationship
ITS Roadway Equipment Manager ITS Roadway Equipment Manages
ITS Roadway Equipment Owner ITS Roadway Equipment Owns
ITS Roadway Equipment Owner ITS Roadway Equipment Manager Operations Agreement
ITS Roadway Equipment Owner Other ITS Roadway Equipment Owner Information Exchange and Action Agreement
ITS Roadway Equipment Owner Traffic Management Center Owner Information Exchange Agreement
ITS Roadway Equipment Supplier ITS Roadway Equipment Owner Warranty
Other ITS Roadway Equipment Manager Other ITS Roadway Equipment Manages
Other ITS Roadway Equipment Owner ITS Roadway Equipment Owner Information Exchange and Action Agreement
Other ITS Roadway Equipment Owner Other ITS Roadway Equipment Owns
Other ITS Roadway Equipment Owner Other ITS Roadway Equipment Manager Operations Agreement
Other ITS Roadway Equipment Supplier Other ITS Roadway Equipment Owner Warranty
Traffic Management Center Manager Traffic Management Center Manages
Traffic Management Center Manager Traffic Operations Personnel System Usage Agreement
Traffic Management Center Owner ITS Roadway Equipment Owner Information Exchange Agreement
Traffic Management Center Owner Traffic Management Center Owns
Traffic Management Center Owner Traffic Management Center Manager Operations Agreement
Traffic Management Center Supplier Traffic Management Center Owner Warranty
Traffic Operations Personnel Traffic Management Center Operates

Maintenance Stage Roles and Relationships

Functional

This service package includes the following Functional View PSpecs:

Physical Object Functional Object PSpec Number PSpec Name
ITS Roadway Equipment Roadway Basic Surveillance 1.1.1.1 Process Traffic Sensor Data
1.1.1.7 Process Road User Protection
1.1.2.11 Control Dynamic Lanes
1.2.7.16 Process Signal Control Conflict Monitoring
1.2.7.2 Monitor Roadside Equipment Operation
1.2.7.8 Provide Device Interface to Other Roadway Devices
1.3.1.3 Process Traffic Images
9.2.3.6 Collect Field Equipment Status for Repair
9.3.3.1 Collect Vehicle Speed
Roadway Field Management Station Operation 1.1.1.5 Provide Sensor Interface to Other Roadway Devices
1.2.7.13 Provide Device Interface for Field Management Stations
Roadway Signal Control 1.1.1.1 Process Traffic Sensor Data
1.2.7.1 Process Indicator Output Data for Roads
1.2.7.13 Provide Device Interface for Field Management Stations
1.2.7.16 Process Signal Control Conflict Monitoring
1.2.7.2 Monitor Roadside Equipment Operation
Traffic Management Center TMC Basic Surveillance 1.1.2.1 Process Traffic Data for Storage
1.1.2.2 Process Traffic Data
1.1.2.3 Update Data Source Static Data
1.1.2.5 Process Vehicle Situation Data
1.1.2.8 Process Roadway Environmental Data
1.1.3 Generate Predictive Traffic Model
1.1.4.1 Retrieve Traffic Data
1.1.4.2 Provide Traffic Operations Personnel Traffic Data Interface
1.1.5 Exchange Data with Other Traffic Centers
1.2.6.1 Maintain Traffic and Sensor Static Data
1.2.8 Collect Traffic Field Equipment Fault Data
1.3.1.1 Analyze Traffic Data for Incidents
1.3.2.1 Store Possible Incident Data
1.3.2.5 Provide Current Incidents Store Interface
1.3.2.6 Manage Traffic Routing
1.3.4.2 Provide Traffic Operations Personnel Incident Interface
1.3.4.5 Process Video Data
TMC Roadway Equipment Monitoring 1.2.8 Collect Traffic Field Equipment Fault Data
1.3.2.6 Manage Traffic Routing
TMC Signal Control 1.1.2.2 Process Traffic Data
1.1.2.5 Process Vehicle Situation Data
1.1.4.1 Retrieve Traffic Data
1.1.4.4 Manage Traffic Archive Data
1.1.5 Exchange Data with Other Traffic Centers
1.2.1 Select Strategy
1.2.2.2 Determine Indicator State for Road Management
1.2.4.1 Output Control Data for Roads
1.2.6.1 Maintain Traffic and Sensor Static Data
1.2.8 Collect Traffic Field Equipment Fault Data

Physical

The physical diagram can be viewed in SVG or PNG format and the current format is SVG.
SVG Diagram
PNG Diagram


Display Legend in SVG or PNG

Includes Physical Objects:

Physical Object Class Description
Cyclist Personal 'Cyclist' participates in ITS services that support safe, shared use of the transportation network by motorized and non-motorized transportation modes. Representing those using non-motorized travel modes, and in particular bicyclists that sometimes share motor vehicle lanes, cyclists provide input (e.g. a call signal requesting right of way at an intersection) and may be detected by ITS services to improve safety.
Driver Vehicle The 'Driver' represents the person that operates a vehicle on the roadway. Included are operators of private, transit, commercial, and emergency vehicles where the interactions are not particular to the type of vehicle (e.g., interactions supporting vehicle safety applications). The Driver originates driver requests and receives driver information that reflects the interactions which might be useful to all drivers, regardless of vehicle classification. Information and interactions which are unique to drivers of a specific vehicle type (e.g., fleet interactions with transit, commercial, or emergency vehicle drivers) are covered by separate objects.
ITS Roadway Equipment Field 'ITS Roadway Equipment' represents the ITS equipment that is distributed on and along the roadway that monitors and controls traffic and monitors and manages the roadway. This physical object includes traffic detectors, environmental sensors, traffic signals, highway advisory radios, dynamic message signs, CCTV cameras and video image processing systems, grade crossing warning systems, and ramp metering systems. Lane management systems and barrier systems that control access to transportation infrastructure such as roadways, bridges and tunnels are also included. This object also provides environmental monitoring including sensors that measure road conditions, surface weather, and vehicle emissions. Work zone systems including work zone surveillance, traffic control, driver warning, and work crew safety systems are also included.
Other ITS Roadway Equipment Field Representing another set of ITS Roadway Equipment, 'Other ITS Roadway Equipment' supports 'field device' to 'field device' communication and coordination, and provides a source and destination for information that may be exchanged between ITS Roadway Equipment. The interface enables direct coordination between field equipment. Examples include the direct interface between sensors and other roadway devices (e.g., Dynamic Message Signs) and the direct interface between roadway devices (e.g., between a Signal System Master and Signal System Local equipment) or a connection between an arterial signal system master and a ramp meter controller.
Pedestrian Personal 'Pedestrian' participates in ITS services that support safe, shared use of the transportation network by motorized and non-motorized transportation modes. Representing those using non-motorized travel modes, pedestrians provide input (e.g. a call signal requesting right of way at an intersection) and may be detected by ITS services to improve safety. This object also includes travelers in special motorized conveyances, which travel at slow speed through portions of the transportation network and interact with ITS systems in a manner similar to that of Pedestrians.
Traffic Management Center Center The 'Traffic Management Center' monitors and controls traffic and the road network. It represents centers that manage a broad range of transportation facilities including freeway systems, rural and suburban highway systems, and urban and suburban traffic control systems. It communicates with ITS Roadway Equipment and Connected Vehicle Roadside Equipment (RSE) to monitor and manage traffic flow and monitor the condition of the roadway, surrounding environmental conditions, and field equipment status. It manages traffic and transportation resources to support allied agencies in responding to, and recovering from, incidents ranging from minor traffic incidents through major disasters.
Traffic Operations Personnel Center 'Traffic Operations Personnel' represents the people that operate a traffic management center. These personnel interact with traffic control systems, traffic surveillance systems, incident management systems, work zone management systems, and travel demand management systems. They provide operator data and command inputs to direct system operations to varying degrees depending on the type of system and the deployment scenario.

Includes Functional Objects:

Functional Object Description Physical Object
Roadway Basic Surveillance 'Roadway Basic Surveillance' monitors traffic conditions using fixed equipment such as loop detectors and CCTV cameras. ITS Roadway Equipment
Roadway Field Management Station Operation 'Roadway Field Management Station Operation' supports direct communications between field management stations and the local field equipment under their control. ITS Roadway Equipment
Roadway Signal Control 'Roadway Signal Control' includes the field elements that monitor and control signalized intersections. It includes the traffic signal controllers, detectors, conflict monitors, signal heads, and other ancillary equipment that supports traffic signal control. It also includes field masters, and equipment that supports communications with a central monitoring and/or control system, as applicable. The communications link supports upload and download of signal timings and other parameters and reporting of current intersection status. It represents the field equipment used in all levels of traffic signal control from basic actuated systems that operate on fixed timing plans through adaptive systems. It also supports all signalized intersection configurations, including those that accommodate pedestrians. In advanced, future implementations, environmental data may be monitored and used to support dilemma zone processing and other aspects of signal control that are sensitive to local environmental conditions. ITS Roadway Equipment
TMC Basic Surveillance 'TMC Basic Surveillance' remotely monitors and controls traffic sensor systems and surveillance (e.g., CCTV) equipment, and collects, processes and stores the collected traffic data. Current traffic information and other real-time transportation information is also collected from other centers. The collected information is provided to traffic operations personnel and made available to other centers. Traffic Management Center
TMC Roadway Equipment Monitoring 'TMC Roadway Equipment Monitoring' monitors the operational status of field equipment and detects failures. It presents field equipment status to Traffic Operations Personnel and reports failures to the Maintenance and Construction Management Center. It tracks the repair or replacement of the failed equipment. The entire range of ITS field equipment may be monitored including sensors (traffic, infrastructure, environmental, security, speed, etc.) and devices (highway advisory radio, dynamic message signs, automated roadway treatment systems, barrier and safeguard systems, cameras, traffic signals and override equipment, ramp meters, beacons, security surveillance equipment, etc.). Traffic Management Center
TMC Signal Control 'TMC Signal Control' provides the capability for traffic managers to monitor and manage the traffic flow at signalized intersections. This capability includes analyzing and reducing the collected data from traffic surveillance equipment and developing and implementing control plans for signalized intersections. Control plans may be developed and implemented that coordinate signals at many intersections under the domain of a single Traffic Management Center and are responsive to traffic conditions and adapt to support incidents, preemption and priority requests, pedestrian crossing calls, etc. Traffic Management Center

Includes Information Flows:

Information Flow Description
crossing call Non-motorized user request to cross the roadway. This is an overt request from a pedestrian, cyclist, or other vulnerable road user. This overt request may be a physical button push or hovering or gesturing in the vicinity of the button that supports contactless activation.
crossing permission Information provided to guide and warn pedestrians at crossings including crossing request acknowledgment, current crossing permission, crossing time remaining, and real-time warnings of safety threats.
driver information Regulatory, warning, and guidance information provided to the driver while en route to support safe and efficient vehicle operation.
local priority request coordination The direct flow of information between field equipment. This includes notification of crossing calls from pedestrians and other vulnerable road users and requests for signal prioritization or preemption, and any other request for right-of-way at an intersection. The status of the priority request is also shared. For vulnerable road users, this includes information provided to guide and warn vulnerable road users at crossings including crossing permission status and crossing time remaining.
right-of-way request notification Notice that a request has occurred for signal prioritization, signal preemption, pedestrian call, multi-modal crossing activation, or other source for right-of-way.
signal control commands Control of traffic signal controllers or field masters including clock synchronization.
signal control coordination The direct flow of information between field equipment. This includes configuration and control of traffic signal controllers or field masters. Configuration data and operational status of traffic signal control equipment including operating condition and current indications are returned.
signal control device configuration Data used to configure traffic signal control equipment including local controllers and system masters.
signal control plans Traffic signal timing parameters including minimum green time and interval durations for basic operation and cycle length, splits, offset, phase sequence, etc. for coordinated systems.
signal control status Operational and status data of traffic signal control equipment including operating condition and current indications.
signal fault data Faults reported by traffic signal control equipment.
signal system configuration Data used to configure traffic signal systems including configuring control sections and mode of operation (time based or traffic responsive).
traffic detector control Information used to configure and control traffic detector systems such as inductive loop detectors and machine vision sensors.
traffic detector coordination The direct flow of information between field equipment. This includes information used to configure and control traffic detector systems such as inductive loop detectors and machine vision sensors Raw and/or processed traffic detector data is returned that allows derivation of traffic flow variables (e.g., speed, volume, and density measures) and associated information (e.g., congestion, potential incidents). This flow includes the traffic data and the operational status of the traffic detectors
traffic detector data Raw and/or processed traffic detector data which allows derivation of traffic flow variables (e.g., speed, volume, and density measures) and associated information (e.g., congestion, potential incidents). This flow includes the traffic data and the operational status of the traffic detectors
traffic image meta data Meta data that describes traffic images. Traffic images (video) are in another flow.
traffic images High fidelity, real-time traffic images suitable for surveillance monitoring by the operator or for use in machine vision applications. This flow includes the images. Meta data that describes the images is contained in another flow.
traffic operator data Presentation of traffic operations data to the operator including traffic conditions, current operating status of field equipment, maintenance activity status, incident status, video images, security alerts, emergency response plan updates and other information. This data keeps the operator appraised of current road network status, provides feedback to the operator as traffic control actions are implemented, provides transportation security inputs, and supports review of historical data and preparation for future traffic operations activities.
traffic operator input User input from traffic operations personnel including requests for information, configuration changes, commands to adjust current traffic control strategies (e.g., adjust signal timing plans, change DMS messages), and other traffic operations data entry.
video surveillance control Information used to configure and control video surveillance systems.
video surveillance coordination The direct flow of information between field equipment. This includes information used to configure and control video surveillance systems and the high fidelity, real-time traffic images and associated meta data that are returned.

Goals and Objectives

Associated Planning Factors and Goals

Planning Factor Goal
A. Support the economic vitality of the metropolitan area, especially by enabling global competitiveness, productivity, and efficiency; Improve the national freight network, strengthen the ability of rural communities to access national and international trade markets, and support regional economic development
D. Increase the accessibility and mobility of people and for freight; Achieve a significant reduction in congestion
E. Protect and enhance the environment, promote energy conservation, improve the quality of life, and promote consistency between transportation improvements and State and local planned growth and economic development patterns; Enhance the performance of the transportation system while protecting and enhancing the natural environment
G. Promote efficient system management and operation; Improve the efficiency of the surface transportation system
I. Improve the resiliency and reliability of the transportation system and reduce or mitigate stormwater impacts of surface transportation; Improve the resiliency and reliability of the surface transportation system

Associated Objective Categories

Objective Category
Arterial Management: Delay
Arterial Management: Reliability
Arterial Management: Traffic Monitoring and Data Collection
Arterial Management: Traffic Signal Management
Special Event Management: Entry/Exit Travel Times
Special Event Management: Use of Technology
System Efficiency: Cost of Congestion
System Efficiency: Delay
System Efficiency: Duration of Congestion
System Efficiency: Energy Consumption
System Efficiency: Extent of Congestion
System Efficiency: Intensity of Congestion (Travel Time Index)
System Efficiency: Travel Time
System Reliability: Non-Recurring Delay
System Reliability: Planning Time Index
System Reliability: Travel Time 90th/95th Percentile
System Reliability: Travel Time Buffer Index
System Reliability: Variability
Transit Operations and Management: Transit Signal Priority
Travel Weather Management: Signal Timing Plans

Associated Objectives and Performance Measures

Objective Performance Measure
Annual rate of change in regional average commute travel time will not exceed regional rate of population growth through the year Y. Average commute trip travel time (minutes).
Crash data for all arterials in the region is reviewed every X years to determine if signal adjustments can be made to address a safety issue. Number of years between reviews of crash data on all arterials for possible signal timing impacts.
Decrease delay by X percent per year by increasing the use of queue jumping and automated vehicle location. Travel time delay on routes with queue jumping and automated vehicle location in use.
Decrease system-wide signal delay on transit routes by X percent per year. System-wide signalized stop delay on transit routes.
Decrease the average buffer index for (multiple routes or trips) by X percent over Y years. The buffer index represents the extra time (buffer) most travelers add to their average travel time when planning trips. This is the extra time between the average travel time and near-worst case travel time (95th percentile). The buffer index is stated as a percentage of the average travel time. Average buffer index or buffer time can be calculated using miles traveled as a weighting factor. Buffer time = 95th percentile travel time (min) – average travel time (min).
Decrease the buffer index for (specific travel routes) by X percent over the next Y years. The buffer index represents the extra time (buffer) most travelers add to their average travel time when planning trips. This is the extra time between the average travel time and near-worst case travel time (95th percentile). The buffer index is stated as a percentage of the average travel time. Average buffer index or buffer time can be calculated using miles traveled as a weighting factor. Buffer time = 95th percentile travel time (min) – average travel time (min).
Decrease the seconds of control delay per vehicles on arterial roads by X percent in Y years. (Control delay is defined as the portion of the total delay attributed to traffic signal operation for signalized intersections). Control delay seconds per vehicle.
Implement special event traffic signal timing plans at X percent of major special events each year beginning in year Y. Percent of major special events each year in which a special event traffic signal timing plan was implemented.
Improve average travel time during peak periods by X percent by year Y. Average travel time during peak periods (minutes).
Increase the miles of arterials in the region operating at level of service (LOS) Z by X percent in Y years. Percent of arterial miles in region operating at LOS Z.
Increase the number of intersections running in a coordinated, closed-loop, or adaptive system by X percent in Y years. Number of intersections running in a coordinated, closed-loop, or adaptive system.
Increase the percent of major special events using ITS-related assets (e.g., roadside cameras, dynamic message signs, vehicle speed detectors) to detect and manage special event entry/exit bottlenecks and incidents by X percent in Y years. Percent of special events using ITS-related assets to detect and manage incidents/bottlenecks at entry/exit routes of the events.
Maintain a program of evaluating X percent of signals for retiming every Y years. Number of traffic signals evaluated for retiming.
Maintain the rate of growth in facility miles experiencing recurring congestion as less than the population growth rate (or employment growth rate). Percent of lane-miles (or rail) operating at LOS F or V/C > 1.0
Reduce average time to clear event's exiting queue by X percent in Y years. Average time to clear event's exiting queue by year per event.
Reduce average travel time into and out of the event by X percent in Y years. Average travel time away from selected special events to a set of locations over a year.
Reduce average travel time into and out of the event by X percent in Y years. Average travel time to selected special events from a set of locations in the area over a year.
Reduce buffer index on arterials during peak and off-peak periods by X percent in Y years. The buffer index (represents the extra time (buffer) travelers add to their average travel time when planning trips in order to arrive on-time 95 percent of the time).
Reduce buffer time index for travelers to multiple similar special events by X percent in Y years. Buffer time index for travelers to multiple similar special events.
Reduce delay associated with incidents on arterials by X percent by year Y. Hours of delay associated with incidents.
Reduce excess fuel consumed due to congestion by X percent by year Y. Excess fuel consumed (total or per capita).
Reduce hours of delay per capita by X percent by year Y. Hours of delay (person-hours).
Reduce hours of delay per capita by X percent by year Y. Hours of delay per capita.
Reduce hours of delay per driver by X percent by year Y. Hours of delay (person-hours).
Reduce hours of delay per driver by X percent by year Y. Hours of delay per driver.
Reduce non-special event VMT in the event area during events by X percent in Y years. Non-special event VMT in the event area during events over a year.
Reduce the 90th (or 95th) percentile travel times for each route selected by X percent over Y years. 95th or 90th percentile travel times for selected routes.
Reduce the annual monetary cost of congestion per capita for the next X years. Cost (in dollars) of congestion or delay per capita.
Reduce the average buffer time needed to arrive on-time for 95 percent of trips on (specified routes) by X minutes over Y years. The buffer index represents the extra time (buffer) most travelers add to their average travel time when planning trips. This is the extra time between the average travel time and near-worst case travel time (95th percentile). The buffer index is stated as a percentage of the average travel time. Average buffer index or buffer time can be calculated using miles traveled as a weighting factor. Buffer time = 95th percentile travel time (min) – average travel time (min).
Reduce the average of the 90th (or 95th) percentile travel times for (a group of specific travel routes or trips in the region) by X minutes in Y years. 95th or 90th percentile travel times for selected routes.
Reduce the average planning time for (specific routes in region) by X minutes over the next Y years. The planning time index represents the time that must be added to travel time at free-flow speeds or the posted speed limit to ensure on time arrivals for 95 percent of the trips. Planning time = 95th percentile travel time (minutes) – Travel time at free-flow speed or posted speed limit. Average planning time index or planning time can be computed using a weighted average over person miles traveled.
Reduce the average planning time index for (specific routes in region) by X (no units) over the next Y years. The planning time index represents the time that must be added to travel time at free-flow speeds or the posted speed limit to ensure on time arrivals for 95 percent of the trips. Planning time = 95th percentile travel time (minutes) – Travel time at free-flow speed or posted speed limit. Average planning time index or planning time can be computed using a weighted average over person miles traveled.
Reduce the number of hours per day that the top 20 most congested roadways experience recurring congestion by X percent by year Y. Hours per day at LOS F or V/C > 1.0 (or other threshold).
Reduce the percentage of facility miles (highway, arterial, rail, etc.) experiencing recurring congestion during the peak period by X percent by year Y. Percent of lane-miles (or rail) operating at LOS F or V/C > 1.0
Reduce the regional average travel time index by X percent per year. Travel time index (the average travel time during the peak period, using congested speeds, divided by the off-peak period travel time, using posted or free-flow speeds).
Reduce the share of major intersections operating at LOS Z by X percent by year Y. Percent of intersections operating at LOS F or V/C > 1.0
Reduce the variability of travel time on specified routes by X percent during peak and off-peak periods by year Y. Variance of travel time. Variance is the sum of the squared deviations from the mean. This can also be calculated as the standard deviation of travel time. Standard deviation is the square root of variance.
Reduce total energy consumption per capita for transportation by X percent by year Y. Total energy consumed per capita for transportation.
Reduce total fuel consumption per capita for transportation by X percent by year Y. Total fuel consumed per capita for transportation.
Reduce total person hours of delay (or travel-time delay per capita) by time period (peak, off-peak) caused by all transient events such as traffic incidents, special events, and work zones. Total person hours of delay during scheduled and/or unscheduled disruptions to travel.
Reduce total person hours of delay (or travel-time delay per capita) by time period (peak, off-peak) caused by scheduled events, work zones, or system maintenance by x hours in y years. Travel time delay during scheduled and/or unscheduled disruptions to travel.
Reduce total person hours of delay (or travel-time delay per capita) by time period (peak, off-peak) caused by unscheduled disruptions to travel. Total person hours of delay during scheduled and/or unscheduled disruptions to travel.
Special timing plans are available for use during freeway incidents, roadway construction activities, or other special events for X miles of arterials in the region by year Y. Number of miles of arterials that have at least one special timing plan for incidents, construction, or events.
Special timing plans are available for use during inclement weather conditions for X miles of arterials in the region by year Y. Number of miles of arterials that have at least one special timing plan for inclement weather events.
X percent of intersections in the region are equipped and operating with traffic signals that enable real-time monitoring and management of traffic flows by year Y. Percent of intersections in the region equipped and operating with traffic signals that enable real-time monitoring and management of traffic flows.


 
Since the mapping between objectives and service packages is not always straight-forward and often situation-dependent, these mappings should only be used as a starting point. Users should do their own analysis to identify the best service packages for their region.

Needs and Requirements

Need Functional Object Requirement
01 Traffic Operations need to be able to remotely control traffic signals at intersections under their jurisdiction Roadway Signal Control 01 The field element shall control traffic signals under center control.
04 The field element shall report the current signal control information to the center.
06 The field element shall return traffic signal controller operational status to the center.
07 The field element shall return traffic signal controller fault data to the center.
TMC Basic Surveillance 02 The center shall monitor, analyze, and distribute traffic images from CCTV systems under remote control of the center.
TMC Signal Control 01 The center shall remotely control traffic signal controllers.
02 Traffic Operations need to be able to manage and implement control plans in order to coordinate signalized intersections. Roadway Basic Surveillance 02 The field element shall collect, process, and send traffic images to the center for further analysis and distribution.
TMC Basic Surveillance 05 The center shall respond to control data from center personnel regarding sensor and surveillance data collection, analysis, storage, and distribution.
TMC Roadway Equipment Monitoring 02 The center shall collect and store CCTV surveillance system (traffic, pedestrian) operational status.
TMC Signal Control 03 The center shall collect traffic signal controller operational status and compare against the control information sent by the center.
05 The center shall manage (define, store and modify) control plans to coordinate signalized intersections, to be engaged at the direction of center personnel or according to a daily schedule.
06 The center shall implement control plans to coordinate signalized intersections based on data from sensors.
07 The center shall manage boundaries of the control sections used within the signal system.
08 The center shall maintain traffic signal coordination including synchronizing clocks throughout the system.
03 Traffic Operations need to be able to monitor and control pedestrian crossing aspects of traffic signals in order to facilitate safe pedestrian crossings at the intersection. Roadway Signal Control 02 The field element shall respond to pedestrian crossing requests by accommodating the pedestrian crossing.
03 The field element shall provide the capability to notify the traffic management center of pedestrian calls and pedestrian accommodations.
TMC Signal Control 02 The center shall accept notifications of pedestrian calls.
04 Traffic Operations need to monitor the status of traffic signal control equipment. Roadway Basic Surveillance 04 The field element shall return sensor and CCTV system operational status to the controlling center.
05 The field element shall return sensor and CCTV system fault data to the controlling center for repair.
Roadway Field Management Station Operation 01 The field element shall accept configuration information from the center.
02 The field element shall pass data provided by the center to local field devices and report data from the field devices back to the center.
TMC Roadway Equipment Monitoring 04 The center shall collect and store CCTV surveillance system (traffic, pedestrian) fault data send to the maintenance center for repair.
TMC Signal Control 04 The center shall collect traffic signal controller fault data from the field.

Related Sources

Document Name Version Publication Date
ITS User Services Document 1/1/2005


Security

In order to participate in this service package, each physical object should meet or exceed the following security levels.

Physical Object Security
Physical Object Confidentiality Integrity Availability Security Class
ITS Roadway Equipment Moderate High Moderate Class 3
Other ITS Roadway Equipment Moderate Moderate Moderate Class 2
Traffic Management Center Moderate High Moderate Class 3



In order to participate in this service package, each information flow triple should meet or exceed the following security levels.

Information Flow Security
Source Destination Information Flow Confidentiality Integrity Availability
Basis Basis Basis
Cyclist ITS Roadway Equipment crossing call Not Applicable High Low
The "Not Applicable" group includes information flows that do not actually carry information; for example, flows that represent the physical environment. Although pedestrians have a responsibility to make sure the road is safe before they cross, and should ensure that they are detected by pedestrian detection systems, they may not always be detected and be led to cross at unsafe times if the ITS RE obtains incorrect information. It is easy to tell whether this information flow is available and pedestrians are used to using crosswalks that do not provide this service.
ITS Roadway Equipment Cyclist crossing permission Not Applicable High Low
This data is intentionally transmitted to everyone via a broadcast. Although pedestrians have a responsibility to make sure the road is safe before they cross, they may react instinctively to incorrect information and be led to cross at unsafe times if they get incorrect information. Also, if the traffic signals are wrong and an accident happens, the pedestrian involved could sue, causing financial loss and other undesirable outcomes. It is easy to tell whether this information flow is available and pedestrians are used to using crosswalks that do not provide this service.
ITS Roadway Equipment Driver driver information Not Applicable High Moderate
This data is sent to all drivers and is also directly observable, by design. This is the primary signal trusted by the driver to decide whether to go through the intersection and what speed to go through the intersection at; if it's wrong, accidents could happen. If the lights are out you have to get a policeman to direct traffic – expensive and inefficient and may cause a cascading effect due to lack of coordination with other intersections.
ITS Roadway Equipment Other ITS Roadway Equipment local priority request coordination Moderate Moderate Moderate
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
ITS Roadway Equipment Other ITS Roadway Equipment signal control coordination Moderate Moderate Moderate
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
ITS Roadway Equipment Other ITS Roadway Equipment traffic detector coordination Moderate Moderate Low
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
ITS Roadway Equipment Other ITS Roadway Equipment video surveillance coordination Moderate Moderate Moderate
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
ITS Roadway Equipment Pedestrian crossing permission Not Applicable High Low
This data is intentionally transmitted to everyone via a broadcast. Although pedestrians have a responsibility to make sure the road is safe before they cross, they may react instinctively to incorrect information and be led to cross at unsafe times if they get incorrect information. Also, if the traffic signals are wrong and an accident happens, the pedestrian involved could sue, causing financial loss and other undesirable outcomes. It is easy to tell whether this information flow is available and pedestrians are used to using crosswalks that do not provide this service.
ITS Roadway Equipment Traffic Management Center right-of-way request notification Low Moderate Moderate
This can be reasonably guessed based on observing the ITS RE's environment. It is obvious when a bus approaches an intersection. Invalid messages could lead to an unauthorized user gaining signal priority at an intersection. This could also be used to delay traffic, which could lead to a financial impact on the community. However, the traffic signal will have controls in place to ensure that it does not display an illegal configuration (such as green in every direction). Even if all of the Right-of-way Requests are not passed along from an ITS RE, the intersection will still operate as normal. There are other existing methods to assist a right-of-way requesting vehicle safely traveling through an intersection, such as lights and sirens, which prevent this from being a HIGH. DISC: THEA and NYC believe this to be LOW: "not necessary for the app to work; can cope with not having immediately available data"
ITS Roadway Equipment Traffic Management Center signal control status Low High Moderate
The current conditions of an ITS RE are completely observable, by design. This influences the TMC response to a right-of-way request. It should be as accurate as the right-of-way request themselves. For some applications (ISIG) this need only be moderate. Per THEA: info needs to be accurate and should not be tampered to enable effective monitoring and control by the TMC. DISC: THEA believes this to be MODERATE: "info needs to be accurate and should not be tampered to enable effective monitoring and control by the TMC; should be as accurate as the right of way request". NYC:TMC doesn't play an active role in this application, i.e. even if the information contained in this flow were incorrect, it is unlikely to affect the outcome of this application one way or the other. On some applications NYC has this MODERATE though. RES: This value can obviously change a lot depending on the application context. The TMC will need the current status of the ITS RE in order to make an educated decision. If it is unavailable, the system is unable to operate. However, a few missed messages will not have a catastrophic impact. From NYC: TMC doesn't play an active role in this application, i.e. even if it is unavailable, it is unlikely to affect the outcome of this application one way or the other. RES: This value can change a lot depending on the application context.
ITS Roadway Equipment Traffic Management Center signal fault data Low High Moderate
The current conditions of an ITS RE are completely observable, by design. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE.
ITS Roadway Equipment Traffic Management Center traffic detector data Low Moderate Moderate
No impact if someone sees the data Some minimal guarantee of data integrity is necessary for all C-ITS flows. THEA believes this to be LOW.only limited adverse effect if raw/processed traffic detector data is bad/compromised; DISC: WYO believes this to be HIGH Only limited adverse effect of info is not timely/readily available, however without this information it will be difficult to perform traffic management activities, thus MODERATE. If not used for management, may be LOW.
ITS Roadway Equipment Traffic Management Center traffic image meta data Low Moderate Moderate
Traffic image data is generally intended for public consumption, and in any event is already video captured in the public arena, so this must be LOW. While accuracy of this data is important for decision making purposes, applications should be able to cfunction without it. Thus MODERATE generally. While accuracy of this data is important for decision making purposes, applications should be able to function without it. Thus MODERATE generally.
ITS Roadway Equipment Traffic Management Center traffic images Low Moderate Low
Traffic image data is generally intended for public consumption, and in any event is already video captured in the public arena, so this must be LOW. Generally transportation coordination information should be correct between source and destination, or inappropriate actions may be taken. While useful, there is no signficant impact if this flow is not available.
Other ITS Roadway Equipment ITS Roadway Equipment local priority request coordination Moderate Moderate Moderate
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
Other ITS Roadway Equipment ITS Roadway Equipment signal control coordination Moderate Moderate Moderate
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
Other ITS Roadway Equipment ITS Roadway Equipment traffic detector coordination Moderate Moderate Low
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
Other ITS Roadway Equipment ITS Roadway Equipment video surveillance coordination Moderate Moderate Moderate
Any control flow has some confidentiality requirement, as observation of the flow may enable an attacker to analyze and learn how to assume control. MODERATE for most flows as the potential damage is likely contained, though anything that could have a significant safety impact may be assigned HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Since this directly impacts device control, we consider it the same as a control flow. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
Pedestrian ITS Roadway Equipment crossing call Not Applicable High Low
The "Not Applicable" group includes information flows that do not actually carry information; for example, flows that represent the physical environment. Although pedestrians have a responsibility to make sure the road is safe before they cross, and should ensure that they are detected by pedestrian detection systems, they may not always be detected and be led to cross at unsafe times if the ITS RE obtains incorrect information. It is easy to tell whether this information flow is available and pedestrians are used to using crosswalks that do not provide this service.
Traffic Management Center ITS Roadway Equipment signal control commands Moderate High Moderate
Control flows, even for seemingly innocent devices, should be kept confidential to minimize attack vectors. While an individual installation may not be particularly impacted by a cyberattack of its sensor network, another installation might be severely impacted, and different installations are likely to use similar methods, so compromising one leads to compromising all. DISC: NYC believes this to be LOW: "The result of this will be directly observable." Invalid messages could lead to an unauthorized user gaining control of an intersection. This could also be used to bring traffic to a standstill, which could lead to a large financial impact on the community. DISC: NYC believes this to be MODERATE: The signal timing is critical to the intersection operation; incorrect signal timing can lead to significant congestion and unreliable operation; while unsafe operation is controlled by the cabinet monitoring system, attackers could "freeze" the signal or call a preemption. RES: This will vary depending on the application and implementation. These messages are important to help with preemption and signal priority applications. Without them, these applications mayl not work. However, if these signals are not received, the ITS RE will continue to function using its default configuration. The TMC should have an acknowledgement of the receipt of a message. DISC: NYC blieves this to be LOW: TMC doesn't play an active role in this application, i.e. even if it is unavailable, it is unlikely to affect the outcome of this application one way or the other.
RES: This will vary depending on the application and implementation.
Traffic Management Center ITS Roadway Equipment signal control device configuration Moderate High Moderate
Control flows, even for seemingly innocent devices, should be kept confidential to minimize attack vectors. While an individual installation may not be particularly impacted by a cyberattack of its sensor network, another installation might be severely impacted, and different installations are likely to use similar methods, so compromising one leads to compromising all. DISC: THEA believes this to be LOW: "encrypted, authenticated, proprietary; however will not cause harm if seen, traffic light information is visible." Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. From THEA: proprietary info that should not be tampered with; includes local controllers and system masters; tampering with configurations could cause delays along with major safety issues Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH. From THEA: should be timely and readily available; however, should be able to function using a default configuration
Traffic Management Center ITS Roadway Equipment signal control plans Moderate High Moderate
Control flows, even for seemingly innocent devices, should be kept confidential to minimize attack vectors. While an individual installation may not be particularly impacted by a cyberattack of its sensor network, another installation might be severely impacted, and different installations are likely to use similar methods, so compromising one leads to compromising all. DISC: THEA believes this to be LOW: "encrypted, authenticated, proprietary; but the result is directly observable from traffic lights Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. From THEA: proprietary info that should not be tampered with; tampering with these plans could cause delays along with major safety issues Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH. From THEA: should be timely and readily available; coordinated with other systems; however, should be able to function using a default configuration
Traffic Management Center ITS Roadway Equipment signal system configuration Low High Moderate
encrypted, authenticated, proprietary; however, the result is directly observable from traffic lights proprietary info that should not be tampered with; data used to configure traffic signal systems; could cause significant delays and traffic issues if compromised should be readily available; configurations can be time
Traffic Management Center ITS Roadway Equipment traffic detector control Moderate Moderate Low
Control flows, even for seemingly innocent devices, should be kept confidential to minimize attack vectors. While an individual installation may not be particularly impacted by a cyberattack of its sensor network, another installation might be severely impacted, and different installations are likely to use similar methods, so compromising one leads to compromising all. DISC: THEA, WYO believe this to be LOW: encrypted, authenticated, proprietary; but should not cause severe damage if seen Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH.. From THEA: should be accurate and not be tampered with; could enable outside control of traffic sensors but should not cause severe harm, but could cause issues with traffic sensor data received and be detrimental to operations Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.. From THEA: want updates but delayed information will not be severe; should be able to operate from a previous/default control/config. DISC: WYO believes this to be MODERATE
Traffic Management Center ITS Roadway Equipment video surveillance control Moderate Moderate Moderate
Control flows, even for seemingly innocent devices, should be kept confidential to minimize attack vectors. While an individual installation may not be particularly impacted by a cyberattack of its sensor network, another installation might be severely impacted, and different installations are likely to use similar methods, so compromising one leads to compromising all. Control flows, even for seemingly innocent devices, should have MODERATE integrity at minimum, just to guarantee that intended control messages are received. Incorrect, corrupted, intercepted and modified control messages can or will result in target field devices not behaving according to operator intent. The severity of this depends on the type of device, which is why some devices are set MODERATE and some HIGH. Control flow availability is related to the criticality of being able to remotely control the device. For most devices, this is MODERATE. For purely passive devices with no incident relationship, this will be LOW. All devices should have default modes that enable them to operate without backhaul connectivity, so no device warrants a HIGH.
Traffic Management Center Traffic Operations Personnel traffic operator data Moderate Moderate Moderate
Backoffice operations flows should have minimal protection from casual viewing, as otherwise imposters could gain illicit control or information that should not be generally available. Information presented to backoffice system operators must be consistent or the operator may perform actions that are not appropriate to the real situation. The backoffice system operator should have access to system operation. If this interface is down then control is effectively lost, as without feedback from the system the operator has no way of knowing what is the correct action to take.
Traffic Operations Personnel Traffic Management Center traffic operator input Moderate High High
Backoffice operations flows should have minimal protection from casual viewing, as otherwise imposters could gain illicit control or information that should not be generally available. Backoffice operations flows should generally be correct and available as these are the primary interface between operators and system. Backoffice operations flows should generally be correct and available as these are the primary interface between operators and system.

Standards

The following table lists the standards associated with physical objects in this service package. For standards related to interfaces, see the specific information flow triple pages.

Name Title Physical Object
ITE ATC Advanced Transportation Controller ITS Roadway Equipment
ITE ATC API Application Programming Interface Standard for the Advanced Transportation Controller ITS Roadway Equipment
ITE ATC ITS Cabinet Intelligent Transportation System Standard Specification for Roadside Cabinets ITS Roadway Equipment
ITE ATC Model 2070 Model 2070 Controller Standard ITS Roadway Equipment
NEMA TS 8 Cyber and Physical Security Cyber and Physical Security for Intelligent Transportation Systems ITS Roadway Equipment
Traffic Management Center
NEMA TS2 Traffic Controller Assemblies Traffic Controller Assemblies with NTCIP Requirements ITS Roadway Equipment