Cross-cutting Issues

Integrating individual intelligent transportation systems into
comprehensive platforms is a key challenge faced by transport authorities in the provision
of optimal services to users. The use of an ITS architecture encourages structured
development and integration of ITS systems that leads to maximization of benefits by
minimizing redundancies and maximizing capabilities. This paper presents a distributed
framework for a multi-layered ITS architecture that has been designed for integrating
information generated and used by future as well as existing intelligent transportation
systems and applications. The iTransIT framework provides a data model that allow
complex ITS domains to be successfully decomposed into a number of data layers. This
multi-layered data model may be distributed across multiple systems and exploits the
overlapping temporal and spatial aspects of traffic information to allow the federation of
data from diverse ITS systems. Moreover, the abstractions used to compose the data
model combined with the range of interaction paradigms supported by the iTransIT
architecture allow interoperation between systems based on different communication
technologies. This provides the framework with the flexibility to enable a gradual
integration of systems over time thereby reducing integration restrictions on previously
deployed systems while catering for the as yet unknown requirements of future and novel
systems.

Trinity College Dublin, Ireland

Presented at the 12th World Congress on Intelligent Transport Systems, November 6-10, 2005, San Francisco, California

While extensive ITS technology is being deployed in the field, it remains difficult to perform formal evaluation of the benefits obtained from the implementation of the technology due to the lack of available evaluation tools. We propose a methodology that uses a simulation/optimization approach to develop a performance versus cost tradeoff analysis curve. In particular, we are evaluating ITS sensor and control technologies such as cameras, ramp metering, loop detectors, etc. Employing CORSIM, a traffic simulation tool, we determine the “optimal” ITS deployment and implementation strategy for a particular budget using a pseudo random search technique. This analysis is repeated over a range of budgets to determine the nature of the cost/performance tradeoff curve. We demonstrate this approach with a six-mile section of interstate in the Hampton Roads region of Virginia.

University of Virginia - Department of Systems Engineering

Presented at the 10th ITS Annual Conference and Exposition, May 1-4, 2000 Boston, MA

Computer simulation has become a widely used tool in transportation engineering with a
variety of applications from scientific research to traffic planning and traffic management
strategies evaluation. In this paper we present a Corsim-based simulation framework that
illustrates the use of a microscopic traffic simulator to model an evacuation operation driven
by real-time control strategies. The framework was developed to assess the performance of a
set of evacuation algorithms previously proposed as part of a Smart Traffic Evacuation
Management System (STEMS). Therefore, our proposed simulation framework will be
presented in the context of STEMS.

University of Central Florida

Florida Atlantic University

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York

This paper presents an effort to develop a simulation testbed for the evaluation
of ramp metering algorithms using CORSIM’s Run-Time Extension (RTE), which provides
exported functions and shared structures to communicate between the CORSIM micro-simulator and the algorithms.  A simulation network with 12 metered on-ramps for an 11- mile
stretch of the I-95 corridor in Miami- Dade County, Florida was used to compare the results
from three alternatives: fixed-time ramp metering control, Seattle fuzzy logic ramp- metering
control, and no ramp metering.  Results show that ramp meters are generally beneficial and
that the Seattle fuzzy logic algorithm with only globally configured parameters outperforms a
well-calibrated fixed-time control strategy especially under congested conditions.  The
simulation testbed developed in this research also makes possible the evaluation of additional
ramp metering algorithms in a widely used simulation model in the United States.

Florida International University

District 6 Florida Department of Transportation

Presented at the ITS America Annual Conference and Exposition, November 16-20, 2008, New York, New York

This paper addresses the distributed position and orientation estimation problem
in ad-hoc vehicle networks using decentralized ltering. Specically, a cooperative distributed
lter for enhancing the estimation accuracy of vehicles state from uncertain position data
is proposed. The lter relies on a variety of position measurements obtained from the on-board vehicle localization system, from other nearby cooperating vehicles, as well as from the
immediate roadside environment via communication. Direct distance measurements between
vehicles and between vehicles and the static elements of the infrastructure can be used, if
available, as highly accurate reference measurements. The paper demonstrates how successfully
the idea of cooperative ltering in addressing the demands of both fault tolerance and enhanced
estimation accuracy in ad-hoc vehicle networks can be used. The availability of the distributed
sensory system that depends on cooperative vehicle communication is a prerequisite of the
applicability of the idea.

Hungarian Academy of Sciences

University of Los Andes

Ramsys Inc.

Presented at the 15th World Congress on Intelligent Transport Systems, November 16-20, 2008, New York, New York