National Evaluation Program FY 2003 Earmark Evaluation: Utah CommuterLink Expansion Case Study Evaluation
The Utah Department of Transportation's (UDOT) Intelligent Transportation System (ITS), known as CommuterLink, was primarily been deployed in the Salt Lake City metropolitan area (Salt Lake County with some coverage on I-15 in Davis and Utah Counties). Utah received a FY 2003 ITS Earmark to expand the CommuterLink system outside of the Salt Lake Valley by integrating the Cities of Orem and Provo, Davis County, and the UDOT Regional Headquarters. With the exception of Davis County, each of these entities now operates its own Traffic Control Centers but would like to operate as a linked system that shares information and coordinates traffic management across boundaries.
According to UDOT statistics posted on the CommuterLink Website, CommuterLink has already helped increase peak-hour freeway speeds by 20 percent and reduce freeway delays, traffic signal stops, and intersection delays by 36, 15, and 27 percent, respectively. Projected savings to travelers in Utah are estimated at more than $100 million each year (1). The computer-controlled system is designed to monitor and manage traffic flow on freeways and surface streets using closed-circuit television (CCTV) cameras; dynamic message signs (DMS); the 511 Travel Information Line; and coordinated traffic signals, ramp meters, and sensors for traffic speed and volume, pavement, and weather.
A key to the success of the CommuterLink Expansion has been that the system is designed to accommodate future expansion and added functionality. Key lessons learned from the CommuterLink Expansion are presented below.
- Build excess capacity into the system and modernize hardware. Building excess capacity into the system and modernizing hardware, as feasible, have helped ensure the successful expansion of the CommuterLink system. This design also has enabled the system to be upgraded as new technologies or system modifications become available. Specific actions taken by UDOT included:
- Building Additional Workstations at the Salt lake City Traffic Operations Center (TOC): Initially, only three workstations were required, so additional room was provided for six workstations to accommodate future expansion.
- Routing Cable Connections: The connecting cables were routed into the TOC through two sides of the building to ensure redundancy by having two separate paths for information flow. Extra conduit banks were added to provide additional capacity.
- Planning Additional Server Space in Existing Locations: Extra space was added in the server locations to allow for future installation of additional servers as required by expansion.
- Accommodating Cabinet Size for Future Installations: Size 6 cabinets were used when installing CommuterLink infrastructure at intersections to ensure that the cabinets had room to accommodate future installations of CCTV and/or video equipment.
- Installing Detectors in all Ramps: Detectors were installed in all ramps rather than only those ramps initially included in the system. This ensured that all ramps were equipped with the necessary infrastructure so that no further installation was required as ramp metering system coverage was expanded as additional ramps brought on line.
- Gather all data at a central location and then devise dissemination schemes tailored to specific applications. UDOT discovered that the system’s expansion significantly increased the amount of data being received. The State determined that the best way to manage the data was for all information to be brought into a central location and then sent out in multiple formats tailored to the application. UDOT determined that standardized data formats and protocols were needed to ensure data consistency and quality as well as ensure that operators were able to properly manage the data being received.
The State also discovered that many organizations were interested in gaining access to the data. Interested groups included Metropolitan Planning Organizations (MPOs) and other groups within UDOT. In addition to developing the standardized data formats and protocols, UDOT also had to provide staffing to manage data and plan for data feeds. The State emphasized the importance of including planning for data management as a key element of project planning, thereby identifying which agencies want access to the data; what data are needed; how data will be used; and how to provide the data to these agencies.
The CommuterLink Expansion project is expected to augment the mobility improvements and cost savings previously reported for the original project (2). Overall, the CommuterLink experience shows that a successful project should be planned to accommodate future expansions.
(1) Utah CommuterLink Website, Frequently Asked Questions (FAQ) page, last accessed June 25, 2008: <http://www.commuterlink.utah.gov/ie.htm>. Benefits information was derived from the following report: Dr. Joseph Perrin, R. Disegni, B. Rama., "Advanced Transportation Management System Elemental Cost Benefit Assessment", University of Utah, March 2004.