Maintain ownership of the work zone ITS system and monitor vendor's work diligently to assure proper system operation.
North Carolina's experience implementing ITS solutions in work zones.
- Require communications and technology experts along with traffic engineering experts to design, implement and test ITS deployments for work zone applications. A hardware / software / communications expert representing the agency should be in regular (e.g., daily) contact with a traffic engineer to ensure full system functionality and that the ultimate goals of the system are achieved. For this deployment, NCDOT engineers coordinated with vendor communications experts to deploy the system. Agencies should not rely on the construction contractor of the system vendor to assure the system is operating as intended.
- Discuss in sufficient detail the concept of operations for the system with the vendor to reach an understanding of exactly how it will process information, and determine what messages to post. The vendor needs to understand the goals the agency is trying to accomplish with the work zone deployment. Technology can easily become a “black box” where data are input and actions result. The deploying agency should be familiar with all aspects of system functionality and should guide the vendor, not the other way around.
- Verify techniques to validate the outputs of the system and refine system operating procedures as needed prior to implementation. Agencies should perform a dry run using a test data set to simulate traffic condition information to monitor the system and verify output before full implementation. In this case the ITS deployment was not completed until after construction started, so the agency had little time to test before implementation.
- Develop performance metrics prior to system implementation to establish specific means of monitoring how well the system worked during the deployment. For this deployment, observation and analysis of interim data proved difficult due to the level of effort needed to access and view preliminary data sets. Therefore, NCDOT relied on the vendor to ensure system functionality and accuracy.
- Use message board controls to prevent conflicting messages from being displayed along the same approach to the work zone area. At this study site, message logs showed that motorists observed conflicting messages, including delay warnings followed by free flow condition messages. This functionality should have been part of the system requirements and tested before implementation.
- Have real-time access to archived system data to identify any issues and monitor system functionality. A Web site could easily provide password protected access to the data being used by the system to make decisions. The Web site for this project provided access to real-time data but did not provide access to the data archives. This too should have been part of the system requirements.
Published By: FHWA
Source Date: October 2008
EDL Number: 14419
Other Reference Number: FHWA-HOP-09-002URL: http://www.ops.fhwa.dot.gov/wz/its/index.htm#its
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