Tailor the standard systems engineering process model to suit an agency’s ITS deployment scale and needs.
Chattanooga Area Regional Transportation Authority's experience in deploying transit ITS
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United States

A Case Study on Applying the Systems Engineering Approach: Best Practices and Lessons Learned from the Chattanooga SmartBus Project


Chattanooga, Tennessee is a city of about 170,000 people (about 500,000 in the metropolitan area) located near the Tennessee-Georgia border. The Chattanooga Area Regional Transportation Authority's (CARTA) provides transit services for the City of Chattanooga and portions of nearby counties. CARTA serves this area by providing fixed-route bus service (16 routes), curb-to-curb transit for people with disabilities (Care-A-Van), a free electric shuttle in the downtown area, an incline railway up historic Lookout Mountain, several parking garages, and management for much of the on-street parking in the downtown area. It is a moderate-sized transit organization in a moderate-sized community. In 2003, CARTA undertook an ITS project, SmartBus, which entailed introduction of many interdependent technologies across the entire range of CARTA operations:

  • Various network technologies were deployed to provide connectivity across CARTA's fixed and mobile assets
  • Technologies were deployed to help automate and modernize many field operations, such as automatic passenger counters and new bus fare boxes
  • Technologies were deployed to help automate and modernize many back office operations, such as new dispatch and revenue management systems
  • A data warehouse was developed to consolidate data collected during CARTA operations, and reporting tools were created to take advantage of this data warehouse

The deployment was challenging and susceptible to risks of failure. Effectively managing the risks, CARTA successfully implemented the SmartBus technologies over a period of 6 years, from 2003 to 2009, with most of the deployment completed. In November 2009, the Intelligent Transportation Systems Joint Program Office (ITS JPO) of the United States Department of Transportation (U.S. DOT) published an independent evaluation report documenting CARTA’s experiences in planning and implementing the SmartBus project. Presented below are lessons learned from CARTA’s experience that could be beneficial to other mid-size transit agencies’ planning for implementation of ITS program.

Lessons Learned

The Chattanooga Area Regional Transportation Authority's (CARTA) SmartBus ITS program offers valuable guidance on applying systems engineering processes for implementing ITS at a mid-size transit agency. Key lessons learned include:

  • Tailor the standard systems engineering process model to suit your agency’s scale and needs. CARTA tailored the standard “V” model of systems engineering to better suit the scale of its organization and the incremental approach it used to develop the overall ITS program through a sequence of individual project deployments [1]. For example, the subsystem and system verification steps were combined in an overall acceptance testing process based on the modest scope of each individual deployment project. There were also opportunities to involve key CARTA end users throughout the project development and implementation process to validate that the system would meet their needs. The processes of Review of Regional ITS Architecture, ITS Needs Assessment, Systems Overview, Operations and Maintenance were used for the entire CARTA ITS program, while Project Deployment Plan, Procurement Specifications, Acceptance Testing and Needs Validation were used for each project. Another set of processes—Design Review, Systems Implementation, and Vendor In-house Testing—were used to perform maintain a collaborative approach between the contractor and CARTA for review and feedback. The application of some of these processes is manifest in the subsequent lessons noted below.
  • Leverage the existing regional architecture to develop a Concept of Operations (Systems Overview) plan for the ITS program. CARTA began its process with a review of the existing Regional ITS Architecture. This included a review of CARTA operations/organization/infrastructure to help identify needs that could be addressed through the deployment of proven ITS technologies and related these needs to the User Services and Market Packages in the ITS Architecture. These efforts helped CARTA explore and define an overall ITS program vision - a system concept overview for how existing and additional technologies could be best integrated to address the agency's needs and situation over the course of developing the overall ITS program. This system overview document defined the ongoing and near-term procurement packages and provided general descriptions of medium- and long-term plans for procurement packages. The systems overview document served as both a planning document and a Concept of Operations for CARTA ITS. The Concept of Operations plan was incrementally updated when needed to reflect the specific effects of individual projects as they were deployed.
  • Develop a deployment plan for individual projects. As individual project procurements were being initiated, CARTA developed a project deployment plan. These plans defined the scope of the individual projects and helped CARTA prepare to successfully transition each project into revenue service once the deployment was completed. It addressed aspects such as organizational impacts, operations and maintenance, monitoring and evaluation, and outreach. The project requirements were documented in the procurement package for the project, including an acceptance matrix that served as the basis for the design review and acceptance testing. The selected project implementation contractor completed a collaborative design documentation and review process with CARTA, prior to developing and deploying the system hardware, software and integration. The project implementation contractor was responsible for in-house testing prior to the start of formal acceptance testing, which was witnessed by CARTA for each subsystem and the overall system. The testing followed procedures that were collaboratively planned in advance with the vendor so as to formally verify all acceptance matrix requirements.
  • Involve the end users in planning, designing, testing, and validating the projects. CARTA involved its end users throughout the process, in developing procurement specifications, contractor selection, design review, acceptance testing, review of training materials and documentation, and the transition into operations and maintenance. This all served to help validate that the project was being developed and implemented so as to address CARTA's needs.
  • Update the Concept of Operations document periodically to effect the completion of each project. As each project was completed, the Concept of Operations (Systems Overview) Plan was updated to reflect the post-deployment situation. This provided another form of validation, as the review of CARTA's post-deployment situation helped CARTA assess the extent to which the project had helped it move towards the vision described in that Systems Overview document. This step and the process of regularly updating the system overview also helped CARTA prepare for eventual changes, upgrades, retirements, and replacements that may be necessary.

The use of systems engineering empowered CARTA with a disciplined approach to improve efficiency and mobility through deploying ITS. The process of preparing the annual updates to the Concept of Operations would provide CARTA with the opportunity to identify the new or changed needs and include those needs in their long-term ITS plans.

A Case Study on Applying the Systems Engineering Approach: Best Practices and Lessons Learned from the Chattanooga SmartBus Project

A Case Study on Applying the Systems Engineering Approach: Best Practices and Lessons Learned from the Chattanooga SmartBus Project
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Haas, R.; E. Perry; J. Rephlo
U.S. DOT Federal Highway Administration

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Goal Areas
System Engineering Elements

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