Active Traffic Management (ATM) applications, such as variable speed limits, queue warning systems, and dynamic ramp metering, have been shown to offer mobility and safety benefits. Yet because they differ from conventional capacity investments in terms of cost, service life, and operating requirements, how to incorporate them into the planning process is not clear. To facilitate such incorporation, this study developed guidelines for considering ATM deployments.
The guidelines consist of four sets. The first set identifies required infrastructure and operational conditions, such as sensor placement and queuing behavior, to apply a particular ATM technique at a given site. The second set presents sketch planning analysis methods to estimate the operational and safety benefits of applying the particular technique at the site; these may be refined with the third set concerning a more detailed (and accurate) simulation analysis. The fourth set concerns continued monitoring of an ATM deployment at a given site. Also provided is a framework for incorporating ATM concepts into the regional planning process. The framework is illustrated with a hypothetical case study of variable speed limits implemented on I-66 in Virginia.
Although Virginia metropolitan planning organizations (MPOs) and the Virginia Department of Transportation already consider operational initiatives to some degree within the planning process, a key finding of this study is that there are several ways to strengthen the inclusion of operational initiatives. These include (1) using the guidelines developed in this study; (2) linking ATM initiatives to the MPO’s Congestion Management Process; (3) facilitating the computation of operational-related performance measures such as total vehicle- hours of delay; and (4) emphasizing, when applicable, the safety and environmental aspects of ATM. The rationale for such aspects is not to promote ATM as being more effective than other types of investments but rather to compare ATM objectively with these other types of investments. For example, Appendix A illustrates how to compute a benefit-cost ratio where costs include capital and operations expenditures for the ATM and where benefits include monetized values of vehicle-hours of delay plus crash costs. In this manner, the benefit-cost ratio for an ATM project may be compared to the benefit-cost ratio for other operational or capacity projects.