The University of Tennessee, Knoxville


AASHTO's Online Tool for TSM&O

by Airton Kohls (Source: AASHTO)

Transportation Systems Management and Operations or TSM&O is a set of strategies to anticipate and manage traffic congestion, and to minimize the other unpredictable causes of service disruption and delay, thereby maintaining roadway capacity while improving reliability and safety. However, implementing the required strategies at the best practice level presents a unique set of new challenges to transportation agency management. The American Association of State Highway and Transportation Officials (AASHTO) has developed a website ( as an online tool that uses self-evaluation and best practice experience to identify key program, process and institutional preconditions to achieve more effective TSM&O, and to develop action plans for incremental improvement of the required capabilities.

Congestion and Degradation of the Level of Service

Roadway congestion has continued to increase over the last 20 years in intensity and in geographic and temporal extent as demand has outgrown capacity, especially during peak periods. The continuing increase in population and vehicle use has–and will–continue to substantially outstrip the ability of new capacity to keep pace.

Causes of Congestion

There is a range of problems that cause congestion:

Delay and disruption is not confined to the recurring congestion of peak period travel. Even in the off-peak period and outside of urban areas, level of service is increasingly unpredictable, owing to crashes, construction, and weather.

Urban and Rural Congestion

While recurring (peak period) congestion is largely an urban phenomenon, non-recurring congestion occurs in all geographic contexts. Crashes, work zones, and weather are the major causes of congestion in smaller urban and rural areas, reflecting their network redundancy limitations and sparse incident response resources. The table below shows these comparisons by indicating the percentage contribution of causes of delay by geographic context.

Graph 3
Source: Summarized in The 21st Century Operations-Oriented State DOT, NCHRP 20-24(21), 2006 from FHWA table combining recurring congestion date (TTI) and non-recurring congestion data (ORNL).

Congestion Self-evaluation Processes

The AASHTO guidance is designed for transportation agency managers whose span of control relates to the operations and management of the roadway system, including policy makers and program managers related to ITS and TSM&O at both the state and regional level, as well as managers of related activities such as traffic engineering, maintenance and public safety. The AASHTO guidance is also designed to provide direction to a given agency via a custom-tailored action plan for improving the performance-related effectiveness of TSM&O activities on a continuous basis. It is based on the understanding that capitalizing on the full potential of TSM&O strategies requires special technical and business processes, organizational structure, and relationships all tailored to the unique features of the high-tech, real-time, collaborative characteristics of TSM&O. As these capabilities are often inconsistent with existing legacy processes and arrangements, a deliberate management approach to improving these processes and arrangements is essential. The stepwise guidance can be custom-tailored to the agency and user through a self–evaluation based on a combination of the user's span of control and interest, the state of play of the agency's TSM&O activities, and the current agency capabilities regarding technical and business processes and institutional arrangements. The evaluation identifies the current level of agency capabilities in key process and institutional dimensions. This evaluation is automatically linked to a set of custom-tailored, "next steps" action plans to improve the levels of agency capability to develop and implement increasingly effective TSM&O. The Guidance can be custom-tailored to the agency through two self–evaluation processes: One-Minute Guidance Evaluation – Based on a snapshot of the agency's current program Detailed guidance is provided for a user with limited time or wishing to "get a feel" for how the full self-evaluation and custom-tailored detailed guidance works. Guidance is provided based on user selection of brief statements describing the agency's TSM&O capabilities regarding technical and business processes and institutional arrangements. Customized Guidance Evaluation – Based on a comprehensive review of the agency's current program Custom-tailored detailed guidance is provided in response to a 15–20 minute self–evaluation that queries a user's span of control and interest, the state of play of the agency's TSM&O activities, and the current agency capabilities regarding technical and business processes and institutional arrangements.

These self–evaluation processes can be found at:


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