Establish a working group among public sector partners to address liability issues.
A Phoenix area experience with establishing procedures for cross jurisdictional signal control.
Made Public Date


Maricopa County
United States

What Have We Learned About ITS?


The U.S. Department of Transportation study "What Have We Learned About ITS?" is a synthesis of the national experience with implementing ITS through the year 2000, with a goal of more effectively planning the future of the National ITS Program. This synthesis examines which ITS technologies and applications have been successful, which have not, and those for which more information is needed to make a judgment. The seven areas included within the scope of this study are as follows:

  • Freeway, Incident, and Emergency Management, and Electronic Toll Collection (ETC)
  • Arterial Management
  • Traveler Information Systems
  • Advanced Public Transportation Systems
  • Commercial Vehicle Operations (CVO)
  • Cross-Cutting Technical Issues
  • Cross-Cutting Institutional Issues

Lessons Learned

An area of potential concern for many metropolitan areas is the sharing of system control by more than a single jurisdiction. This is a frequent concern for jurisdictions that operate a traffic signal control system with arterials that cross one or more jurisdictions. To reduce liability, good planning and engineering practices must be exercised when establishing procedures to share control among agencies.

Some public sector partners in the Phoenix metropolitan area note that liability issues in their area have already been resolved through discussions in the Signals Working Group, a regional group that looks at coordinating traffic signals along corridors running through several jurisdictions. Through their involvement in the working group, participants are confident that only appropriate actions will be taken when representatives of one jurisdiction assume temporary control of another jurisdiction's traffic signal system.

Engineers in the Phoenix area established the following practices within the Signals Working Group to avoid potential liability issues.

  • Define and document a series of thresholds under which signal plans can be altered.
  • Establish written coordination policies and plans to cover signalized corridors bordering multiple jurisdictions.

The key to overcoming any constraint is to acknowledge its likelihood and address it early. Project participants should anticipate these obstacles and come to the table prepared to discuss them.

This lesson illustrates how a metropolitan area can work together to circumvent any liability issues that may surface by establishing a discussion group and developing a set of plans and procedures to share traffic signal control among multiple jurisdictions. Cross jurisdictional signal control can lead to significant benefits for a region having considerable impact on the performance of a corridor and contributing to the achievement of several ITS goals including: safety, mobility, efficiency, and customer satisfaction. Addressing liability issues and documenting procedures in a working group forum relieves some of the reservations agencies may have when it comes to considering cross jurisdictional signal control.

What Have We Learned About ITS?

What Have We Learned About ITS?
Publication Sort Date
Joseph Sussman, et al. (MIT)
Federal Highway Administration, U.S. DOT
Other Reference Number
Report No. FHWA-OP-01-006

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Focus Areas Taxonomy: