Plan to recalibrate traffic sensors to accommodate lane shifts and other changes near work zones.

Experience using multi-jurisdictional ITS to support freeway work zone operations.

Date Posted
01/23/2015
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Identifier
2014-L00686

Lessons Learned

Managing Work Zone Traffic: The Freeway and Arterial System for Transportation (FAST) system in Las Vegas.



This research examined the use of a multi-jurisdictional ITS system to assist traffic management during construction and maintenance in Las Vegas. Management of permanent ITS assets were integrated. Local agencies handled the basic maintenance needs of the arterial ITS infrastructure (signals, cameras for signal detection) and the FAST program handled the maintenance of freeway assets (CCTV cameras, traffic sensors, ramp meters, and dynamic message signs). In 2012, the overall system included approximately 1,000 field devices.



FAST facilitates work zone management by disseminating work zone traffic information on a dedicated website. However, most FAST support is dedicated to the operation of roadside dynamic message signs (DMS) used to inform travelers of deteriorating traffic conditions at work zones and provide advanced notice of work zone construction schedules. The messages displayed inform drivers of ongoing lane restrictions but leave it up to the drivers to identify and select an appropriate alternate route. FAST Operators are trained to identify when a DMS message is needed, and the proper way to design and post the messages.



The following recommendations were offered by FAST management personnel.

  • Engage ITS personnel early in the work zone planning process. Inclusion of ITS personnel early in the design process can improve scheduling and the strategic use of ITS resources and assets.
  • Provide travelers with advanced notice of lane change configurations or other temporary traffic control conditions prior to construction. Work zone crash risk is highest during the first few days of a project. A permanent system such as FAST can be beneficial in getting the word out to travelers a few days in advance of such changes.
  • Plan to recalibrate traffic sensors near work zones to accommodate lane shifts and other changes during construction. Depending on how the contract is written, the contractor may be required to recalibrate not only the temporary sensors, but the sensors for the permanent system as well. This recalibration effort takes time and effort. It is important to check that resources have been allocated for this activity by the contractor.
  • Retain a good electrical subcontractor with ITS device experience and include them in activities that directly or indirectly interact with ITS components. A lack of such experience on the contractor team can cause problems in getting system components installed and operating properly. It is important to request and assess contractor qualifications when reviewing project bids.
  • Evaluate how traffic related messages on DMS affect driving decisions and behavior. The posting of a particular message can lead to significant diversion in some cases, but not in others. Train operators to tailor messages to achieve desired results.
  • Establish and maintain a good relationship with the media to maximize the effectiveness of ITS. FAST experiences have shown that being proactive in getting information out to the media can pay dividends by helping to influence the messages that the media is putting forth.
  • Have a programmer on staff who understands how a particular ITS deployment has been designed and managed. A good programmer can be extremely useful in designing user interfaces, data archival methods, and other analytical elements required by operators and managers.
  • Organize ITS deployment data using data management tools that enable easy data archiving and retrieval. Centers such as FAST generate tremendous amounts of data. Enabling data to be retrieved by attributes such as location and time can be very valuable for both real-time work zone traffic management and performance measurement activities. For example, it makes it easier to see and track trends over time, can aid decision making for lane closure requests, and can improve incident management efforts if operators can quickly assess how previous incidents in the same location and time of day affected travel patterns.

The ability to coordinate both arterial and freeway operations gives FAST an advantage that few transportation agencies possess across the nation. Although a formal evaluation was not conducted during this project preliminary data show that overall work zone operations improved when FAST data were available to support decision making.