Evaluation of the Operational and Safety Effects of the I-66 Active Traffic Management System (ATMS)
Michael Fontaine, Ph.D., Emily Parkany, Ph.D., PilJin Chun
A project to install an Active Traffic Management (ATM) system on Interstate 66 from US 29 in Centreville to the Capital Beltway (I-495) has been under way since early 2013 with an estimated completion date of early 2015. I-66 is a highly congested highway during both peak and off-peak hours with unpredictable traffic patterns. This project will install smart infrastructure and employ techniques that mobilize ATM, which will ideally produce safety and operational improvements on I-66 without physically widening the roadway. The key components of ATM that will be installed on I-66 include advisory variable speed limits, queue warning systems, hard shoulder running, and dynamic ramp metering. ATM has been successful in producing safety and operational improvements in many European countries, but there are limited ATM application in the US. Since ATM is still a relatively new approach in the US, there is a need to analyze the safety and operational effects of ATM on I-66.
Appropriate operational performance measures and safety measures will be defined, examined and analyzed n order to conduct a before-and-after study to quantify the effectiveness of the ATM system on I-66. Operational measures of effectiveness will include average travel time, travel time reliability, duration of congestion, queue length, delay and throughput. Safety measures of effectiveness will include speed compliance, crash characteristics, and incident frequency. After the completion of the before-and-after studies, a preliminary benefit-cost ratio will be calculated to show the ATM system’s value relative to the cost of construction and maintenance. The results of this study could be used to evaluate the merit of proposed ATM projects on other corridors in the state.