Cross-cutting Issues

Abu Dhabi Department of Transport (DoT) recently completed and ITS Strategy and Action
Plan that provides a roadmap for transportation management and technology projects, including development of a multi-modal transportation management center (TMC). The plan has received full Government support to move ahead with initial ITS and TMC development, emphasizing deployment of active traffic management, travel time information, and pre-trip traveler information systems along with a signature TMC that will incorporate freeway and public transport operations, and will be connected to existing local traffic control centers handling urban traffic control activities.

Authors: Glenn N. Havinoviski, PE, Salah Mohammed Al-Marzouqi, Ra'id Breiwish, Ph.D.

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The concept of the car following theory, the manner in which two cars follow one another without passing, has been closely studied in the last decades. As applied to traffic engineering and safety research, many models were developed to best mimic the interaction between adjacent vehicles in a traffic stream. The car following theory also forms the process of the microscopic traffic simulation models which attempt to replicate driver behavior in a traffic stream. Though most existing applications are limited to historical traffic data, wide utilization of new data collection tools, such as Global Position System and Automatic Vehicle Identification technologies are expected to lead to rapid improvements in existing car following models. The large amount of real-time traffic data provides a possibility to better calibrate and validate car following models to better represent the traffic conditions. This study summarizes the commonly used car following models, and discusses the applications and limitations of each. Using current limitations, this study also discusses the future potential improvements of car following models with new technologies, such as the real-time traffic information provided by the intelligent transportation technologies.

Authors: Yiming He, Mashrur Chowdhury, Ph.D., Taufiquar Khan, Ph.D., Yan Zhou Ph.D.

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

Automatic vehicle sensors provide link traffic flow data in a transportation network which is valuable information to address long-term traffic planning and short-term operational needs of the transportation agencies. However, these sensors and their deployment are expensive, leading to the strategic problem of the identification of the subset of links on which to install them to maximize the information on link flows using a limited number of sensors. The need to estimate flows on the maximum number of possible links based on the measurement of link flows on a subset of links that have sensors installed on them, leads to the network sensor location problem (NSLP). Mostly, the NSLP is either solved as a sub-problem of broader problems such as origin-destination (O-D) matrix estimation, or by focusing on long-term
planning considering static traffic conditions. Since, in an operational context, traffic conditions change with time and multiple paths are used as the traffic evolves, there is the need to consider the dynamic traffic conditions in the NSLP. In this study, we formulate the NSLP to capture the traffic dynamics using the dynamic link-path incidence matrix which indicates the time-dependent presence of flow on links. This problem is then solved over the horizon of interest to obtain the subset of links that provide maximum expected network-level observability through sensors installed on them. In each time interval, the dynamic link path incidence matrix is used to compute the “basis links,” that is, the subset of links that provide complete observability of the network. The set of basis links computed in each time interval is used to identify the subset of links to install sensors on by maximizing observability gain from the links while considering the maximum number of sensors available for installation. The approach is useful for deploying short- term operational/long-term planning and link-based applications in traffic networks.

Author: Sushant Sharma

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The SafeTrip-21 (Safe and Efficient Travel through Innovation and Partnerships for the 21st Century) initiative was established to test and evaluate integrated, intermodal ITS applications, particularly those that do not entail extensive public sector infrastructure but can achieve immediate benefits and demonstrate the potential for sustainable deployment. These efforts and resulting applications support the U.S. DOT goals to improve safety, reduce congestion, and advance the nation’s transportation system. A total of 8 applications were deployed and tested across two test beds. SAIC was selected to conduct an independent national evaluation of these technologies which concluded in May 2011 and provided lessons learned to the ITS community related to technology use, consumer response, user-perceived benefits, and technical and institutional issues. Keywords: real-time traveler information, smart phones, geofencing, in-vehicle safety warnings, transit, multi-modal trip planning, probes, connected vehicles.

Author: Christopher Armstrong

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

Author:      John A.A. Opiola

Senior Partner/Vice President

D’Artagnan Consulting LLC

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida