Research Overview

Passive interaction between fixed and mobile transportation system entities is rapidly giving way to a new paradigm of connected, interacting entities. This enables both new forms of data exchange and the opportunity to extend the geographic scope, nature, precision and latency of control within the transportation system. This opportunity to transform control of individual mobile or fixed entities as well as the connected system of mobile and fixed entities may have transformational impact on the capability of the transportation system to support individual mobility, system productivity and economic activity, while at the same time reducing environmental impacts and safety risks.

Introducing new forms of control may not necessarily increase the centralization of control systems.  Some applications, for example transit signal priority, may be best deployed as a decentralized, locally optimized application.  Such a local application might combine precise predictions of pedestrian and vehicular location over time in an intersection with transit passenger count and schedule adherence data from transit vehicles approaching the intersection.  Considering these data, a local automated decision to adapt signal control to accommodate a specific transit vehicle might be made.  The altered signal plan is then communicated using two-way connectivity between the infrastructure and vehicles, including not only transit vehicles but all vehicles approaching the intersection. This example illustrates that new forms of control may exploit both new data and improved connectivity within the system.  However, the example also illustrates a consideration of an appropriate level of control and how systems that combine local, corridor and network-level controls perform.  In many cases, decentralized but coordinated systems can be cost-effective alternatives to centralized systems.

Another desired element in new forms of control is the ability to accurately characterize and monitor both near-term control impacts and long-term system performance.  Localized intersection control might routinely assess passenger-weighted intersection throughput against pre-determined target values.  Corridor or system-level controls integrating data from vehicles, travelers and local infrastructure control systems could characterize network-level mobility and productivity.  These routine assessments could be used to fine-tune control settings as well as measure improved mobility and productivity over time.