Ensure proper sequencing of ITS deployments with careful consideration to dependencies among projects and utilize a data warehouse to lessen complexity in ITS integration.
Chattanooga Area Regional Transportation Authority's experience in deploying transit ITS
Made Public Date


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 sequencing projects and using data warehouse for implementing ITS at a mid-size transit agency. In 2004, CARTA developed a SmartBus System Overview Update report documenting a long-term vision of how agency wanted to use ITS. The report included, among other things, an implementation schedule. Lessons learned on the usefulness of having an overview/operations plan, especially for ITS project sequencing and integration, are narrated below.

  • Ensure proper sequencing of ITS deployments with careful consideration to dependencies, and avoid the temptation to do too much too fast. CARTA strove to introduce changes incrementally, avoiding the temptation to do too much too fast. Doing too much too fast can increase the deployment risks because problems in developing one system can impact development of a second system dependent on the first. A review of the CARTA deployment schedule indicates that CARTA avoided simultaneously deploying systems that included strong dependencies among them. Examples include:
    • The first system deployed was the data warehouse, which pulled data from a number of existing systems. Since most other systems in CARTA's ITS plans would integrate with the data warehouse, deploying it first helped ensure that the data warehouse was operating stably when new systems were deployed.
    • Ticket vending machines (TVM) and the demand-response and fixed-route transit operations software were deployed in 2006. These systems were integrated with the data warehouse requiring little additional integration as the data warehouse was already operational to capture and process new data.
    • In 2007, CARTA provided network connectivity to CARTA vehicles. This ensured that the network connectivity needed to support CAD/AVL was in place in advance of the CAD/AVL deployment. By the time computer-aided dispatch / automated vehicle monitoring (CAD/AVL) systems were deployed and integrated with the operations software in 2009, the operations software was tested and stable.
  • Be flexible to accept schedule adjustments—to accelerate or delay—when needed to help manage deployment risks in ITS integration. In 2008, CARTA fast-tracked several system elements needed to support the real-time bus arrival time signs. At the time that the University of Tennessee at Chattanooga approached CARTA with the real-time bus arrival time sign opportunity, many system elements necessary to support real-time bus arrival time information—for example, onboard location and route tracking equipment, ability to load the onboard run databases from Trapeze-FX [1] via the wireless local area networks (WLAN), and network connectivity to the buses—were already in place. However, other needed system elements were still not deployed. For example, the CleverCAD [2] system was going to be used to access bus location archives needed to estimate run times, and the real-time bus schedule adherence data were needed to estimate arrival times. Also needed were elements from the BusTime system, including the arrival time website server and the signs themselves. So, in this particular case, CARTA elected to deploy the BusTime system, the arrival time website server, and the bus stop dynamic message signs in 2008 despite the original intention to deploy these elements after the CAD/AVL software deployment that was well underway. To offset the risks from accelerating the deployment on specific elements of the program, CARTA deferred the rollout of the AVM and APC (automatic passenger counter) and slowed the CAD/ AVL deployment to allow the agency and its contractors to focus on elements needed for the bus arrival time predictions system. Thus, even when CARTA needed to adjust the schedule to accelerate some elements, it simultaneously accepted delays on other elements to help offset the risks of simultaneous deployments.
  • Develop and use an ITS data warehouse to lessen overall system complexity in integrating multiple ITS applications. CARTA’s early deployment of the data warehouse helped reduce complexity of integrating various projects. Early in its ITS deployment process, CARTA recognized the need to integrate data from different sources to support CARTA operations. An example of this was integrating fuel and maintenance cost data to calculate the total cost of vehicle operations so that the most cost-effective vehicles could be identified. One approach for doing this would have been to interface each of the ITS applications with every other ITS application for which integration was needed. Deploying a data warehouse allowed CARTA to achieve the same capabilities by integrating each ITS application with only a single other application – the data warehouse.

CARTA’s experience provides ample evidence that preparing a systems overview or concept of operations plan early on is a useful exercise. As narrated above, identifying the mutual dependencies among ITS applications, sequencing the projects synergistically, and lessening the complexity of ITS integration are some of the key activities that can benefit significantly from having a system overview/operations plan.

[1] Trapeze-FX is a fixed route schedule builder and vehicle and driver assignment system.
[2] CleverCAD is an advanced technology solution that delivers high levels of efficiency and security to transit operations by giving dispatchers and supervisors a clear, real-time picture of the location and status of every bus on the road.