Report describes motivation for TMC expansion effort, details on staffing changes, the performance measurement methodology, and assessments of benefits and costs.
Austin, Texas, United States
Performance Evaluation for City of Austin Transportation Management Center Expansion
Summary Information
The City of Austin, Texas Transportation Management Center (TMC) works to monitor traffic patterns, deploy resources to address equipment issues, implement signal timing adjustments, and aid in special event management with the ultimate goal of improving traffic operations in Austin. In April 2016, the City decided to expand operations of the TMC to address the City’s increasing congestion challenges resulting from a fast-growing population. The goals of this TMC operation and capability expansion were to increase staff coverage and flexibility, increase the hours of center operation, improve operational efficiency, help manage incidents and events, and ultimately improve transportation system performance.
The addition of consultant staff enabled the City to expand the hours of TMC operation during weekdays, to include an additional 30 minutes in the morning (6:00 am–6:30 am) and an additional 90 minutes in the evening (6:30 pm–8:00 pm), as well as providing coverage on Saturdays (nine hours) and Sundays (eight hours). Beyond expanding the daily hours of operation, additional staff resources have been included during the weekday peak periods. An on-call manager was also added for special events. With the TMC expansion, the number of person-hours spent monitoring traffic increased by nearly 100 percent each week.
A benefit-cost analysis was performed that considered the benefits of TMC lane-blocking responses and additional signal retiming. All benefits and costs were estimated over the April to December 2016 analysis period.
- Lane-Blocking Response: TMC expansion enabled more off-peak signal retiming for lane-blocking incidents. The analysis assessed 18 intersections classified as involving two busy streets (“Major-Major”) and 18 classified as having minor side streets (“Major-Minor”) to estimate off-peak benefits during the analysis period. Field data and engineer logs were used as inputs.
- Expansion of the Annual Signal Retiming Program: The TMC expansion enabled City staff to address signal issues rather than day-to-day operations of the TMC, as well as to achieve more efficiency in coordination of resources with consultant staff. Following the expansion, 60 hours per week were redirected, allowing engineers to retime twice as many signals as was done previously. Of the 173 retimed signals within the April-December analysis period, 87 of these were attributed to TMC expansion. The benefit analysis for the expanded signal retiming program was based upon before-and-after measurements of retimed signal performance. The data was collected from probe vehicles that measure travel time during the AM peak, the PM peak, and off-peak hours.
- Special Case Retiming: The expansion also permitted signals to be retimed on a special-case basis depending upon the severity of an observed daily recurring bottlenecks. Such efforts are performed outside the Annual Signal Retiming Program. The most prominent example of a special-case signal retiming effort made possible through TMC expansion involved a pair of signalized intersections on N. Lamar Boulevard at 5th and 6th Streets. These intersections often experienced a heavy amount of left-turn traffic around lunchtime, blocking through traffic. In a special July 2016 effort which included monitoring of the intersection pair at the TMC and modeling in simulation, traffic engineers devised a unique timing scheme to reduce the possibility of intersections and through traffic being blocked.
Findings from TMC Expansion Activities, April–December 2016
|
Activity |
Hours of Delay Saved - Resulting Cost Savings |
|
Lane-blocking response |
15,120 hours - $337,478 |
|
Expansion of the annual signal retiming program |
65,765 hours - $1,467,893 |
|
Special-case retiming |
121,943 hours - $2,721,760 |
|
Total benefit |
$4,527,131 |
|
TMC expansion cost |
$1,237,329 |
|
Benefit-Cost Ratio |
3.7 |
Performance Evaluation for City of Austin Transportation Management Center Expansion
The University of Texas at Austin
