Intelligent Transportation Systems in Work Zones: A Case Study - Work Zone Traffic and Incident Management System - Keeping Traffic Moving During Reconstruction of the Big I, a Major Interstate-Interstate Interchange in Albuquerque
The New Mexico State Highway and Transportation Department (NMSHTD) rebuilt the Big I interchange in Albuquerque to make it safer and more efficient and provide better access. The original Big I was severely over-capacity. NMSHTD employed an ITS-based mobile traffic monitoring/management system to help move vehicles through the extensive construction area. ITS components were deployed prior to construction with plans to later incorporate portions of the system into a permanent freeway management system.
NMSHTD used ITS for several reasons:
- Changes in traffic patterns, closures and alternate routes required that travelers be provided with high-quality real-time information.
- The high volume of traffic moving through the interchange created great potential for congestion.
Three main project goals included:
- Provide traffic management capabilities and traveler information on traffic routing, detours, and incidents.
- Minimize capacity restrictions due to incidents.
- Enhance traveler safety.
The project included cameras and sensors to monitor traffic conditions and detect incidents, electronic signs, highway advisory radio, a website, and other media to transmit traveler information. Incident detection was a major component. Lessons learned related to the importance of a reliable communication system, scheduling and planning, public awareness, interagency coordination, and consideration of future maintenance requirements.
It is important for agencies deploying ITS resources to conduct necessary pre-implementation measures in order to ensure smooth system operations. In light of their experience deploying ITS at the Big I interchange rebuilding in Albuquerque, The New Mexico State Highway and Transportation Department (NMSHTD) found a number of ways to help ensure operational efficiency of ITS resources.
- Grant ample start up time when implementing new ITS technologies. Problems will arise, such as with sensor operation, communications (wireless or wireline), license applications, component calibration, hardware, or software. These issues will take time to address and need to be identified as soon as possible before going "live".
- The mobile traffic monitoring and management system used by NMSHTD for the Big I interchange ITS deployment in Albuquerque was designed to be portable and use wireless communication. Wireless communication links were tested prior to the installation of field elements to ensure adequate bandwidth availability.
- The complete mobile traffic monitoring and management system was brought on-line two weeks prior to the start of construction. This allowed for thorough pre-construction testing.
- Maintain flexibility throughout the implementation process. The ability to remain flexible allows agencies the ability to quickly reconfigure system components on an as needed basis. Based on experiences during the Big I interchange ITS deployment in Albuquerque NMSHTD realized that:
- ITS units deployed in the core of the work zone should be highly portable. Because work zone configurations are likely to change frequently, ITS units will need to be moved regularly.
- When making changes to roadway geometry, allow time for drivers to learn the new traffic pattern before reporting problem spots to the contractor based on observations from the system's cameras.
- Consider the future when planning and deploying a traveler information system. Because New Mexico's State Highway and Transportation Department planned for future use, the agency used a combination of equipment purchases and rentals for its project to rebuild the "Big I" interchange in Albuquerque. Once the project ended, NMSHTD was able to reuse the purchased equipment as part of a permanent freeway management system.
- Perform maintenance needs in-house with some initial vendor assistance. This allows agencies to reduce costs by not having to rely solely on a vendor for maintenance support. While experience varies from project to project on the subject of in-house vs. contracted maintenance, in this instance, in-house maintenance was the appropriate selection.
- For the Big I interchange NMSHTD coordinated extensively with the incident management community and obtained Federal Highway Administration (FHWA) assistance to help patrol the work zone area.
Before implementation of any ITS resource, deploying agencies need to conduct pre-planning that will ensure fluid operations throughout the life span of the system. From their experience deploying ITS at the Big I interchange rebuilding site NMSHTD found that allowing sufficient start up time is key, in order to work out any bugs in the system before full scale implementation. It is, as always, in the best interest of any agency deploying ITS to maintain an element of flexibility throughout the implementation process in order to be able to respond to dynamic conditions. Also of considerable importance is planning to have as much future maintenance done in-house as possible, this saved both time and money for NMSHTD.