U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
California Division
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[Please note that the solution given here is for this example only. Other viable solutions may be possible and each must be evaluated for a given project.]
This project involves replacing an obsolete traffic signal management system with a new system. This system uses computers located at City Hall to provide remote monitoring and control of traffic signals. The existing system is no longer supported by the manufacturer. It is unreliable and not maintainable. It lacks the functionality needed and available in more modern systems. A needs & feasibility study identified needs, high-level requirements, investigated the capabilities, and costs of available off-the-shelf traffic signal management systems. It concluded that an off-the-shelf system using existing communications infrastructure will suffice. However, the existing signal controllers [not cabinets], central computers, and software will need to be replaced. The estimated project cost is $1,500,000, exclusive of on-going operation and maintenance costs. There is no immediate need for center-to-center interaction between this system and other systems. The stakeholders desire is to exchange data in the future.
This is a relatively straight-forward project that requires a low to moderate level of systems engineering. The absence of new software development, use of COTS components, re-use of existing communications infrastructure, and absence of integration with other systems… all reduce risk and complexity. On the other hand, selection of the optimum system, ensuring the new system operates effectively, achieving a smooth transition from the old system to the new, ensuring operations & maintenance personnel are adequately trained, and having the project completed within budget and schedule will require careful project management [including appropriate systems engineering].
| Process Step | Estimated Level of Effort |
Check list of supporting activities | Check list of issues | Check list of risks | Examples |
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Feasibility |
Medium |
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Definition of the need: "Provide a traffic signal management system that is reliable, maintainable, and provides the needed functionality". Source of quote Feasibility: Do available off-the-shelf products address the need? How much of the existing equipment and infrastructure will need to be replaced or upgraded? Is there an affordable solution? Trade study and cost benefit: Evaluate alternative approaches, such as retaining existing computers, controllers, cabinets, and communications infrastructure versus replacing some or all of these. Consider alternative communications protocols, their impact on initial and future product choices, communications infrastructure requirements, and options. Stakeholder issues: Consider performance measurement, needs of management, monitoring, control features needed by operations personnel, and self-diagnostic features needed by maintenance personnel. Risk management: Ask product vendors for input and cost estimates to ensure proposed solution is feasible and affordable Base analysis on mature, proven products Forego requirements that would require modification to off-the-shelf software or hardware Give preference to flexible, standards-based solutions |
Planning |
Medium 3-5 pages
Systems Engineering Management Plan |
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The identified systems engineering plans might include: Deployment Plan Verification and Validation Plans Project Plan Operations & Maintenance Plan Risk Management Plan
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Concept of Operations and Validation Plan |
Low 1-2 pages
Traffic signal management systems are well understood and do not need an elaborate concept of operations or Validation Plan |
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How the system will operate: Central software will continuously monitor the operation of traffic signals, reporting current status, traffic flow data, and alarms. The system automatically synchronizes the clocks in signal controllers and commands controllers to change timing patterns when appropriate. Operators periodically check status, update signal timings, respond to alarms, use collected data in various analyses, add new signals to the system, and use the system to temporarily adjust signal timings during incidents. Measures of effectiveness for validation: Traffic signal equipment failures are reliably detected and appropriate personnel notified in a timely manner Data collected by the system are successfully used for traffic analysis and signal timing refinement Adjusted signal timings are downloaded reliably when needed The system is used to temporarily adjust signal timings during incidents. Controller clocks are kept synchronized System users give favorable reports as to the ease of use and effectiveness of the system The system has a low failure rate and does not require an unreasonable amount of maintenance The number of citizen complaints that could be avoided by an effective system is reduced |
Development of System Level Requirements and Verification Plans |
Low - Medium 2-4 pages Requirements and 2-4 page Verification Plan |
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Definition of what the system is to do to support the identified needs. "The traffic signal system shall automatically synchronize controller clocks at a user-selectable time of day." "The system shall allow users to upload and store controller data sets." "The system’s central software shall operate on personal computers using the Windows operating system." "The system shall provide three workstations.". What will be used for the basis of verification and acceptance of the system? Verification Plan would include, for example: Configure the server clock to update the time in the near future and check that the test controller’s clock changes to match the server’s clock at that time Upload a designated controller’s data set, store the data, restart the database server, check that the stored data are available and match that in the controller What will be needed to support operations & maintenance? Users and maintenance documentation shall be provided. System configuration documentation shall be provided |
System design |
Low - medium 5-8 pages Design Document including map and diagrams |
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Examples of design elements:
Including any cabinet wiring changes, controller options, communication protocol choice, computer furniture, graphics style. Map showing location of signals to be integrated in the new system and communication infrastructure used. Any cabinet wiring modifications Controller firmware version to be installed Process for converting and transferring existing controller data sets to the new controllers Any new racks and furniture needed at central Configuration of computers Graphics style and source of base drawings Naming conventions Definition of signal groupings Cutover Plan Training Plan Project costs Revised cost estimate based on final system design
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Development of Component Level Design |
No detailed component-level design needed since all system components are off-the-shelf.
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Hardware and software development
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Not needed, since all components are off-the-shelf
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Unit verification |
Defined by the Deployment Plan and Verification Plan |
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Inspect and test the units of software and hardware Computers and installed software – before any signals are connected Controllers and installed firmware – stand alone bench tests |
Unit integration |
Defined by the Deployment Plan |
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Integrate components into sub-systems Prepare and install a test controller in a bench cabinet. Connect the bench controller in a cabinet to the communications server Install software and data sets in all controllers, ready for installation |
Sub-system verification |
Defined by the Verification Plan and Verification Procedures |
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Verification of sub-systems for functionality Verify that the central software can successfully communicate with a test controller on the bench Test system functionality with the bench controller connected |
Sub-system integration |
Defined by the Deployment Plan |
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Integrate sub-systems into the final system’s configuration Make any needed modifications to cabinets in the field. Install new controllers in the field. Complete installation of computers and other central equipment. Connect field controllers to the central communications server. Complete central software configuration |
System verification |
Defined by the Verification Plan |
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System passes all acceptance tests. Perform system-level acceptance tests in accordance with the Verification Plan All documentation is updated and ready for users All user training, maintenance, and user manuals are completed. The system configuration is fully documented |
Deployment |
Since this is a replacement system, deployment has already occurred by this stage. |
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Validation |
Defined by SEMP Validation Plan |
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System evaluation Does the system provide the benefits expected? Are users able to use it effectively? Are field equipment faults reported reliably and quickly? Is it reliable and easy to maintain? |
Operations & Maintenance |
Defined by the Operations & Maintenance Plan |
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On-going operation and maintenance. Ensure operations staff are available and using the system as needed Arrange vendor support contracts if needed, after warranty period Provide operation & maintenance training for new employees Maintain spare parts inventory Keep system configuration documentation up to date Track system shortcomings and additional needs Plan changes & upgrades when needed. |
Changes & upgrades |
Defined by the new project SEMP |
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Examples of reasons to change or upgrade Equipment or software may become obsolete May need to add a center-to-center connection May need to add cameras or signs |
