Safety

A Probabilistic Model And A Software Tool For AVCS Longitudinal Collision/safety Analysis

Tsao, H. S. Jacob
Hall, Randolph W.
1993

This paper develops a probabilistic model and a software tool for analyzing longitudinal collision/safety between two automated vehicles. The input parameters are the length of the gap between the two vehicles, the common speed prior to failure, the reaction delay of the following vehicle and a bivariate joint distribution of the deceleration rates of the two vehicles. The output includes the probability of a collision and also the probability distribution of the relative speed at collision time. The model is used to compare the safety consequences associated with the platooning and "free-...

Robust Computation of Optical Flow in a Multi-Scale Differential Framework

Weber, Joseph
Malik, Jitendra
1993

We have developed a new algorithm for computing optical flow in a differential framework. The image sequence is first convolved with a set of linear, separable spatiotemporal filters similar to those that have been used in other early vision problems such as texture and stereopsis. Our analysis of the measurement errors leads us to develop an algorithm based on a robust version of total least squares. Each optical flow vector computed has an associated reliability measure which can be used in subsequent processing. The performance of the algorithm on the data set used by Barron et al. (...

Optimization Tools For Automated Vehicle Systems

Shiller, Zvi
1995

This work focuses on computing time-optimal maneuvers which might be used to develop strategies for emergency maneuvers and establishing the vehicle' s performance envelope. The problem of emergency maneuvers is addressed in the context of time optimal control. Time optimal trajectories are computed along specified paths for a nonlinear vehicle model, which considers both lateral and longitudinal motions.

A Method for Relating Type of Crash to Traffic Flow Characteristics on Urban Freeways

Golob, Thomas F.
Recker, Wilfred W.
2003

A method is developed to determine how crash characteristics are related to traffic flow conditions at the time of occurrence. Crashes are described in terms of the type and location of the collision, the number of vehicles involved, movements of these vehicles prior to collision, and severity. Traffic flow is characterized by central tendencies and variations of traffic flow and flow/occupancy for three different lanes at the time and place of the crash. The method involves nonlinear canonical correlation applied together with cluster analyses to identify traffic flow regimes with...

Driving Intelligence Replacement in a Decision-Oriented Deployment Framework for Driving Automation

Tsao, H.-S. Jacob
Ran, Bin
1996

What some human drivers have done wrong has been blamed for much of the problem associated with the current highway systems. For example, driver inattention, fatigue and other human errors have often been cited as major sources of safety hazard on current highways and human capabilities as major limitations on current highway capacity. Such human deficiencies and the pervasive urban traffic congestion have motivated the concept of Automated Highway Systems (AHS). The fundamental objective of AHS is to achieve user and societal benefits through replacing human driving by automated machine...

Median Light Rail Crossing: Accident Causation And Countermeasures

Coifman, Benjamin
Bertini, Robert L.
1997

This paper focuses on accident causation and countermeasures at arterial median light rail grade crossings. It synthesizes accident causation and prevention literature from several fields, including traffic engineering, human factors and cognitive psychology, as it relates to the complex LRT grade crossing.

Supply Side Evaluation of Radio Traffic Information

Yim, Youngbin
Pfeifle, Brian
Hellman, Paul
1997

The study investigated data collection and dissemination processes of radio traffic information in the San Francisco Bay Area. Program directors from thirty two radio stations were interviewed to understand the processes and radio traffic reports were analyzed to evaluate the contents. The study showed that morning traffic conditions were broadcast most frequently. During morning peak hours from 6AM-9AM, the majority of the stations broadcast traffic conditions every 15 minutes. The content of the radio information is limited to traffic flow, incident conditions and transit schedule. The...

Configuration And Maneuvers In Safety-consciously Designed Ahs Configuration

Hitchcock, Anthony
1995

This paper sets out a configuration for an Automated Highway System (AHS) which is believed to have advantages from a safety viewpoint. The configuration and operating principles are described. The scheme requires that vehicles change lanes directly from platoon to platoon, and that entry and exit be made also without platoons merging or splitting on the automated lanes. The protocols for the maneuvers needed are described in detail.

Effects of Traffic Density on Communication Requirements for Cooperative Intersection Collision Avoidance Systems (CICAS)

Shladover, Steven E.
2005

Intersection collisions are difficult to mitigate or eliminate by use of ITS technologies for a variety of reasons. These include the complexity of the driving environment and of the driver decision making process at intersections, but also the difficulty of accurately detecting the movements of all potentially conflicting vehicles. Prior research by Calspan-Veridian Engineering (now part of General Dynamics) (1) showed the near impossibility of detecting the relevant information using vehicle-mounted sensor systems. Current research under the IDS program is revealing the challenges...

Notes From a Talk on Standards and IVHS Safety

Hitchcock, Anthony
1991

This paper records a personal understanding of some features of the needs for standards and codes of practice in IVHS, and of the present position regarding them, in so far as the author has:a. perceived them to be relevant to his own studies in the AVCS field in the U.S., mainly in relation to full automation.b. been able to obtain access to the appropriate documents; he does not have easy access to a library containing defense standards.