Knowledge Resources

ADMS offer numerous potential benefits, including the ability to better evaluate system performance, plan for operations, and support future investment decisions. Washington State TRAC, for example, uses its ADMS to assess performance of the HOV lane system, to plan work zone control, and to plan for the use of reversible lanes for special events. Archived data provides Caltrans with a powerful tool for system performance monitoring and congestion management, and the Minnesota TMC also uses its ADMS to support traffic monitoring and effectiveness of traffic control devices such as ramp meters.

During the planning and design phases of archived data management systems (ADMS), there are a number of issues that transportation agencies need to consider to ensure the success of their project. Based on the experience of the six sites profiled in this study, the following set of lessons learned highlight key issues regarding the requirements definition and system design phases of ADMS projects.

• Define the audience that will be the main system users so as to understand their data and application needs. The Minnesota TMC’s database format is structured to facilitate query response to support a broad range of users and applications. Data formats used by the system therefore include commercially available relational database applications. Moreover, system developers focused on ensuring that all data are centralized and distributed via the Internet (though individual applications could be distributed or localized).
• Teach engineers and planners that are helping to define ADMS applications to think "outside the box" to derive maximum benefit from the system. However, be prepared to provide boundaries as users may ask for capabilities they will rarely, if ever, use.
• Consider that some database formats may be easy to manage and inexpensive initially, but may require a high level of programming support which is expensive.
• Address firewall and security issues as early as possible.
• Use commercially available or open source software over proprietary or custom designed systems. Early ADMSs such as Washington State TRAC and Minnesota TMC have a history of sharing software code with other public sector ADMS developers. Sharing of code may result in development of a set of standard practices to assure that minimum quality standards are addressed. The Maricopa County RADS will rely largely on open source software to address data collection. Open source software is well suited for the wide variety of data types that the Maricopa County RADS is expected to store and process. The system will collect data via the Internet, CD-ROMs, or dedicated landlines, depending upon the agency providing the data.
• Develop a configuration plan for system software and hardware.
• Ensure proper documentation of software (especially if university students are used for software development)
• Include mapping tools in requirements developed for applications.
• Bring maintenance staff into the process early and develop coordination procedures to ensure the loop functionality will be preserved

Through careful attention to requirements definition and system design, transportation agencies can derive maximum benefit from an ADMS, as they are able to more effectively gauge system performance and to more efficiently plan future operational strategies. Ultimately, the objective of this applied research is to improve the safety, mobility, and efficiency of the transportation network.