The National Academies

NCHRP 20-07/Task 392 [Final]

Plan for an AASHTO Operations Guide
[ NCHRP 20-07 (Research for AASHTO Standing Committee on Highways) ]

  Project Data
Funds: $99,999
Research Agency: Parsons Brinckerhoff
Principal Investigator: Les Jacobson
Effective Date: 6/20/2016
Completion Date: 11/3/2017


The objectives of this project were to (1) investigate the focus for, potential use and topics to be included within the context of an “Operational Standards for Highway Infrastructure” document and (2) develop a roadmap for conducting research needed in order to develop such a document.


The contractor's final report is available. Further work is being conducted as NCHRP Project 03-126.


Based on discussions with operations professionals, knowledge of the industry, and familiarity with existing AASHTO guides, the following tasks are anticipated in this project:
  • State of the practice review. This task will include web and literature searches to find what is currently documented for operations guidance, both in terms of processes and procedures, typical design features that support operations, and typical deviations that are approved because operations features mitigate the need for such stringent design standards. The state of practice review will also include recent and emerging research such as updates to the TRB Freeway Operations Guide and the Reliability Research Program from the Strategic Highway Research Program 2 (SHRP2).
  • Interview and/or survey of operations professionals and operating agencies to supplement the information gathered in the first task.
  • Present findings from the above work tasks and facilitate a meeting of a project panel drawn from experts representing the AASHTO Design, Traffic and Systems Operations and Management subcommittees as well as representatives of ITE, ITS America and FHWA
  • Based on guidance from the panel identify and recommend needed revisions to the AASHTO Green Book or the development of a stand-alone equivalent for TSMO.
  • Develop a roadmap for a research program needed to complete revisions to the Green Book or develop a stand-alone equivalent for TSMO. 


For decades the AASHTO Policy on Geometric Design of Highways and Streets (the Green Book) has been a foundational guidance document for determining the geometric features of our nation’s highway system. This guidance is based research and general assumptions of how geometric elements affect system performance. This standard continue to define the traditional perspective of highway infrastructure, and thereby drive a significant portion of highway investments. The Green Book continues to provide the content that is the basis for the design standards that are adopted and deployed nationally as well as at a state and local level. 

As transportation agencies look for ways to maximize the effectiveness of this highway infrastructure, operational strategies are becoming broadly recognized as necessary and cost effective in accomplishing system performance objectives. These strategies often bring with them ability to effect driver behavior, with direct connection to how drivers react to the conditions they encounter along their route, both in terms of real time non-recurrent events, as well as static features such geometric elements. These strategies rely upon a different definition of infrastructure, and provide the ability to influence and in some cases redefine tradition geometric elements.

Ultimately to support decision making processes, various analysis tools and methodologies continue to be developed and refined to better align with the needs and performance expectations of the users of the highway system, as well as to reflect new strategies available to system providers. These include the WZ safety and mobility improvements resulting from 2004 FHWA WZ Rule making and the advancements in MUTCD to address the integration of ITS and other future technology procedures. The latest efforts of the Strategic Highway Research Program (SHRP 2) developed enhanced methodologies to assess safety, capacity, and reliability that lay the groundwork for considering cross cutting strategies that incorporate both operational and geometric features. These tools are now in early implementation phases across the country.

These three aspects when considered together drive the initiative for a formalized TSMO program that goes beyond operating efficiency to providing the best way to develop, manage, and operate transportation networks and infrastructure. In support of this comes the need for a new perspective on how we look at and consider highway infrastructure, and a new way to think about “standards” associated not only with infrastructure, but also with system management capabilities as necessary components to accomplishing performance.

Steps moving forward could include:

  • Identification of operational strategies and associated elements that should be considered “standard” features of the highway system. This includes both urban and rural aspects of the highway system taking into the operational condition of a facility and the system management capabilities necessary to meet performance objectives;
  • The integration of operational strategies, geometric features, and analysis techniques to consider new approaches in determining highway design criteria and system elements. This blending of highway features and services would be invaluable in effectively moving from a “design exceptions” driven approach to a “right sized” approach in determining system investment needs; 
  • Consideration of how these efforts could be served by the development of an “Operational Standards for Highway Infrastructure (an operations Green Book)” document and/or how these approaches could be incorporated in existing documents.

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