Safety

Active traffic management consists of a series of integrated congestion management strategies including speed harmonization, queue warning, hard shoulder running, dynamic rerouting, travel time signs, ramp meter control, managed lanes, etc. This study aims to provide a comprehensive review and comparative analysis on various active traffic management strategies and their application. The detailed analyses of the key technologies are provided, and the system benefit, safety, and equity concerns are addressed in this paper. The findings of this study indicate active traffic management systems demonstrate the great potential for freeway congestion mitigation and safety enhancement.

Department of Civil, Architectural and Environmental Engineering, University of Texas

Department of Civil Engineering, University of New Mexico

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

Emergent Collision Avoidance Systems (CAS's) are beginning to assist drivers in performing specific tasks and extending the limits of driver's perception. The systems face significant hurdles in terms of safety and driver acceptance. In fact, CAS's may actually make the driving environment more dangerous. This paper demonstrates that adaptive capability is necessary to mitigate these concerns. Specifically, CAS's must adapt to a driver's style and limitations. Fortunately, a significant portion of this adaptive capability can be realized without additional sensors and with the inclusion of relatively simple hardware. The requirements of components of a CAS are discussed based on advances found in recent relevant literature. An architecture for an adaptive CAS is proposed.

The George Washington University - GW Transportation Research Institute

Presented at the ITS America Annual Conference and Exposition, April 29 –May 2, 2002 Long Beach, California

Emergent Collision Avoidance Systems (CAS's) are beginning to assist drivers in performing
specific tasks and extending the limits of driver's perception. The systems face significant
hurdles in terms of safety and driver acceptance. In fact, CAS's may actually make the driving
environment more dangerous. This paper demonstrates that adaptive capability is necessary to
mitigate these concerns. Specifically, CAS's must adapt to a driver's style and limitations.
Fortunately, a significant portion of this adaptive capability can be realized without additional
sensors and with the inclusion of relatively simple hardware. The requirements of components
of a CAS are discussed based on advances found in recent relevant literature. An architecture for
an adaptive CAS is proposed.

The George Washington University

Presented at the ITS America Annual Conference and Exposition, April 29-May 2, 2002, Long Beach, California

We present an adaptive communication scheme for Cooperative Active Safety
System (CASS). CASS uses information communicated from neighboring vehicles via
wireless communication in order to actively evaluate driving situations and provide warnings
or other forms of assistance to drivers. In CASS, we assume that vehicles are equipped with a
GPS receiver, a Dedicated Short Range Communications (DSRC) transceiver, and in-vehicle
sensors. The information exchanges between vehicles include position, speed, heading, and
other vehicle kinematic and dynamic information, and the information is broadcast to all
neighbors within a certain communication range. The literature surmises CASS may need a
vehicle to broadcast information as often as every 100 msec which may lead to channel
congestion resulting in message loss rates above 20%. Here we present a new communication
design scheme, supported by simulations, which indicates that CASS could be enabled by
broadcasting, on average, as little as once every 500 msec.

California PATH, UC Berkeley

GM R & D Center

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

The new telematic-based road traffic control technologies enable the application of a large
number of various control strategies. Ranging from the fix-time control to adaptive control
there is a whole series of combined strategies that eventually depend only on the skills of the
traffic expert who by choosing traffic parameters realizes for a certain traffic demand in the
given physical conditions, the optimum of throughput capacity and safety.
Sometimes this is a difficult task and does not always lead to the desired results.
The fact is that experience and practice with the implementation of advanced technologies
have the best chance of achieving the best possible results.
The work shows an example of adaptive control and the safety results "before" and "after" at
an intersection in the City of Zagreb.

Transport and Traffic Engineering, Zagreb, Croatia

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