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Publication Number: FHWA-HRT-06-095
Date: May 2006
It is critical to gather detailed information about the existing infrastructure elements that support coordinated operations during the technology inventory, The inventory is completed to accurately identify locations that are deficient in deployment of data collection, traffic control, and information dissemination systems, as well as their related data analysis and communication systems. Recording details of the existing technology types, brands, protocols, and means of communication will enable engineers to determine whether existing technologies and their components are compatible, interoperable, and interchangeable. Knowledge of the existing systems will define the ability to communicate between them. It will also define future system deployments, because it is essential that new technologies deployed can communicate with, operate with, and be controlled by existing systems.
The level of data collection depends on the degree of complexity of the application and the long-term plans for coordinated operations. The examples given start on the basis of a complex application. The inventory may be less extensive for simpler applications. However, it is better to collect as much information as practical the first time, because requirements often change as systems are developed. A second trip to collect additional information is time consuming, so erring on the side of an excess of information is often a wise investment of time.
Performing an inventory of freeway and arterial data collection systems, traffic control systems, information dissemination systems, and communications networks is best accomplished with an inventory system that is a combination of a database, configuration management software, and geographic information systems (GIS). It is recommended that data input to the inventory system makes use of a form for every piece of equipment inventoried. The inventory of communications networks should focus on collecting information about the types of wireline and wireless networks that are in place, their functions, their available capacity, and their transmission modes to define the ability for future devices to communicate on existing networks, the need for additional capacity on existing systems for future devices, or the need for new communication systems altogether for future devices.
Completing the inventory for field devices, such as detectors, surveillance cameras, RWIS, ramp meters, traffic signals, DMS, and HAR, will require significant time to complete, particularly for systems with significant amounts of deployment with few records of the existing systems. Performing the inventory for central systems, however, should not require as much effort. It will only require the information recorder to gather information about individual systems, such as parking management systems, motorist call-in systems, reversible HOV lane systems, and central data analysis systems, at a few locations.
Ultimately, after populating the inventory system, it will enable a user to:
Although the inventory system described above is the most comprehensive and useful for assessments, it is rather time-consuming and costly to populate and maintain. Agencies constrained by limited staffing and budgets may only be able to accomplish an inventory that makes use of manual formats or only involves necessary data input without a GIS map.
Performing the inventory for data analysis systems and communications systems is drastically different from that described above because these systems consist of algorithms, firmware, central software, and integration of systems that enable processing, transmission, and receipt of information for CFA operations. These systems may reside in the field or at control centers.
Because there are multitudes of data analysis systems and communications systems that can comprise CFA operations, it is advisable in performing an inventory to first consider all the concepts of operations that were envisioned and then outline the data analysis systems and communications required between control centers to achieve each operations concept. An example data analysis system and communication system inventory process for a coordinated ramp metering concept of operations follows.
Ramp Metering Data Analysis System
Does your data analysis system analyze the following to determine the best metering rates?
Is the detector and control system data received often enough? Are you analyzing the most appropriate types of data (i.e., should you receive and analyze speed, occupancy, and volume data instead of only receiving speed data?)?
Ramp Metering Communication System
Can control center operators of the ramp meter owning/controlling agency:
Can the traffic signal control owning/controlling agency and other jurisdictions perform the functions listed above for the ramp meter owning/controlling agency? Can the agencies control the traffic signal operations to give less green-time to phases that send vehicle platoons to the freeway ramp when the ramp is at capacity?
Following completion of the inventory of all infrastructure elements, agencies must determine whether they can accomplish their concept of operations for each coordination management operations plan through the existing infrastructure for all desired areas of a corridor. Agencies should consider traffic data collection systems, traffic control systems, information dissemination systems, communications networks, data analysis systems, and communications systems that can be deployed to better CFA operations. If the infrastructure is insufficient, agencies should use the inventory to identify which locations require further infrastructure deployment.
Performing an Infrastructure Needs Assessment
When an agency that operates and maintains arterials performs a needs assessment, they should consider deployment needs on their own road networks and on the freeway networks that will enable the agency to improve operations on their own system via coordination with the freeway. Conversely, an agency that operates and maintains freeways should consider deployment needs on the freeways and on adjacent arterials to improve operations on their own system through coordination with the arterials. Freeway and arterial agencies should work together to complete a needs assessment, particularly when the agencies have a specific coordination applications goal, such as planned special event management coordination. The first recommended step is for each agency to independently answer the needs assessment questions.
The next step is for the agencies to meet to discuss their identified needs and prioritize deployment needs for achieving the coordination goal. The following questions address the process of needs assessment:
Specific Infrastructure Needs Assessment Questions
Additional example infrastructure needs assessment questions for specific deployment on freeways and arterials, specifically for recurring and nonrecurring congestions, are included in the following sections.
Recurrent Congestion Infrastructure Needs
Nonrecurrent Congestion Infrastructure Needs
Recurrent Congestion Infrastructure Needs
Nonrecurrent Congestion Infrastructure Needs
In most circumstances, budgetary constraints will be a
Future deployments should use technologies that apply national ITS standards to enable future systems integration as legacy systems are replaced.
significant factor in making deployment decisions; therefore, agencies should consider all of their deployment needs and associated cost estimates to develop a prioritized deployment list. To develop a complete list of deployment needs, agencies should answer questions similar to those above and complete infrastructure needs forms for each concept of operations they generated for every type of CFA operations application. They can then compare this information to determine which deployment efforts will enable accomplishing multiple goals and to prioritize deployment based on cost effectiveness, immediate needs, and ability to bring systems online. Consider this example. It is determined that 2 ramp meters, 9 ramp detectors, 56 arterial midblock detectors, and 4 CCTV cameras should be deployed for ramp metering efforts for day-to-day management coordination and traffic incident management coordination. CCTV cameras and detectors are also desired for upcoming planned special event management coordination within the same area. If sufficient funds are not available to deploy all of the technologies in this case, the best choice is to implement only the surveillance cameras and some detectors first. If agencies are focusing on a particular CFA operations application, they may want to perform only a needs assessment for that application.
In comparing desired uses of an existing communications network, agencies can determine whether deployments will exceed available capacities, and if so, they will need to prioritize deployment or add capacity to the network.
Another issue that must be considered in assessing deployment needs is the level of compatibility between disparate communication systems. If various agencies operate and maintain technologies that are incompatible, agencies should develop a comprehensive plan to trade out equipment or integrate systems to enable CFA operations. Future deployments must use technologies that apply national ITS standards to enable future systems integration as legacy systems are replaced.
Integration of Interagency Systems
Stakeholders identify and document information they want to share between their field devices and control center systems in a concept of operations document and in accordance with their regional architecture. They must then assess the compatibility and available capacity of existing control center systems, field devices, and communications systems to assess the best means of integrating their systems.
Although the control center system integration assessment will make use of the data analysis and communications systems inventory, it will also involve a detailed assessment of all system components within each center. This includes individual data elements employed in system software, software code, the ability to modify software elements and modules, control center equipment protocols and configurations, video and data networks, control system capabilities, and workstation features. The selection of appropriate systems integration between control centers must incorporate ITS standards, including center-to-center and traffic management data dictionary.
The field device and communications systems assessment will make use of the traffic data collection systems, traffic control systems, information dissemination systems, and communications network technology inventories. Stakeholders will need to review the features of field devices, such as data inputs and outputs, protocols, standards, and means of communications to assess interfacing abilities directly from the field and via control centers. The communications systems assessment will involve reviewing the location of existing wireline and wireless networks and their available capacities, system protocols, and networking parameters to determine whether the existing communications systems can support the desired systems integration.
Following these assessments, the final step will be to develop a deployment and migration plan for deploying communications network components, replacing field devices, updating system firmware, updating existing control center system settings, deploying control center systems, developing new software modules, writing software code to deploy standards, and bringing the integrated systems online to enable CFA operations.
While electronics can deliver information from the field to the control center and send it back out to the drivers, the information by itself is of little use without coordination among the many stakeholders. ITS and other electronic systems can play a significant role in this area. Part of the coordination challenge is making sure all the stakeholders get the information they need when they need it. So much information can be gathered that it must be put in context to be of use. This can be accomplished through filtering systems that make certain only the information needed is provided to each individual agency.
Timeliness is also a critical part of systems coordination. Information should be delivered to all stakeholders simultaneously and as soon as it is verified. If one agency is operating with out-of-date information, they may be taking actions out of sync with
Part of the coordination challenge is making sure all the stakeholders get the information they need when they need it.
other stakeholders. Timeliness is also critical to the largest stakeholder group, the traveling public. If information is old and no longer accurate, the value of the system is not only diminished during the incident in question, but for future incidents as well. An example might be information displayed by one agency on a DMS that conflicts with information being broadcast on another agency's HAR system.
Accuracy is a third important piece of systems coordination. Control centers need to be able to give stakeholders 100 percent accurate information, even if that information is not 100 percent complete. For example, the control center may know there is a slowdown eastbound at milepost 28.3 without knowing the reason for the slowdown. It must be certain not only that it delivers the information, but that it is understood. ITS can play a role here by providing the information in a consistent, easily understood format, by taking additional steps such as plotting the location on a map and by automatically identifying the surveillance tools that can monitor the incident.
Effectively providing traveler information across agency jurisdictional boundaries within a region requires the integration of the above data to traffic control centers and center-to-center linkages. It is encouraged that a region develops a regional architecture to facilitate the implementation of these system and data interfaces. The result will be a traveler information center/system (virtual or staffed) that disseminates information via:
Communication is needed with the media to support information sharing with stakeholders. Therefore, data and video links to the media may be required. This would allow the media to provide coordinated and accurate information, such as recommending alternate routes around congestion.
Keywords: arterial operations, freeway operations, regional operations, corridor operations, corridor management, traffic operations corridor
TRT Terms: Express highways--United States--Management--Handbooks, manuals, etc, Traffic engineering--United States--Handbooks, manuals, etc, Traffic congestion--Management--United States--Handbooks, manuals, etc, Expressways, Traffic engineering, Traffic congestion