Safety

Expedited Crash Investigation - With Use of Technologies for Documentation and Processing

Chan, Ching-Yao
Lian, Thang
Ko, Jeff
2007

The mobility and efficiency of California highways are impeded by the recurrent and non-recurrent congestion on a daily basis. Roadway incidents, especially collisions, often result in traffic congestion and travel delays. This project is initiated to explore the use of technologies that will potentially bring direct and immediate benefits to the law enforcement officers and other personnel who are involved in the handling of collision sites and subsequent investigations. The work carried out in this project includes three major components: (1) The experimentation of integrated vehicular...

Lateral Control Of Tractor-semitrailer Vehicles In Automated Highway Systems

Chen, Chien
Tomizuka, Masayoshi
1996

In this paper, linear quadratic optimal control with and without frequency shaping is utilized to design a steering controller for tractor- semitrailer vehicles in Automated Highway Systems (AHS). To enhance driving safety, the authors propose to use independent braking forces in the trailer as another control input. The combined steering and braking controller is designed by utilizing Input/Output linearization and backstepping design techniques.

High Collision Concentration Location: Table C Evaluation and Recommendations

Ragland, David R.
Chan, Ching-Yao
2007

This report describes the research work that was conducted under PATH Task Order 5215 and its extension Task Order 6215, “Methods for Identifying High-Concentration Collision Locations (HCCL).” The subject matter is related to regularly published Caltrans reports, so-called Table C, that are used to screen for and investigate locations within the California State Highway System that have collision frequencies significantly greater than the base or expected numbers when compared to other locations. The accuracy and reliability of such reports are critical as Table C is the basis for follow-...

STC Matching Grant Annual Report

Rodriguez, DA
2008

While the conventional approach to safety planning has emphasized crash analysis with police-reported crash information, transportation professionals increasingly recognize the importance of identifying potential crash risk and considering environmental characteristics. In this proactive approach, individuals’ perception of crash risk provides important information in identifying potential crash risk. As built environment characteristics such as the presence of crosswalks, sidewalks, and number of lanes, are expected to influence the levels of pedestrian and bicycle safety, this study...

Optimal Emergency Maneuvers Of Automated Vehicles

Shiller, Zvi
Sundar, Satish
1996

This work addresses two issues related to emergency maneuvers of autonomous vehicles. The first concerns the time-optimal speeds along specified path, which can be used to design emergency maneuvers. The second concerns the computation of optimal lane-change maneuvers for on- line collision avoidance. Although considering only a simple planar vehicle model, this work provides insights into the dynamic behavior of ground vehicles

Lateral Control Of Front-wheel-steering Rubber-tire Vehicles

Peng, Huei
Tomizuka, Masayoshi
1990

In this paper, two models were developed to describe the lateral dynamics of a vehicle for different purposes. The lateral feedback and feedforward controllers are designed to satisfy the above objective based on a linearized model, which includes only the lateral and yaw motions. The performance of the controllers is evaluated on a complex model, which includes motions in all six directions (longitudinal, lateral, vertical, roll, pitch and yaw). It has been validated by numerical simulations that the responses of the complex model and the simplified model remain close to each other when...

A First Example Specification Of An Automated Freeway

Hitchcock, Anthony
1991

This paper presents a specification for an automated freeway in a fully formal manner. A series of safety analyses have been carried out on the specification. The objective of the program is to derive a technique of safety analysis for such systems. Readers are advised to consult " Methods for Analysis of IVHS Safety: Final Report of PATH MOU 19" by the author for background information to this report.

Assessing Automated Speed Enforcement in California

Chan, Ching-Yao
Li, Kang
Lee, Joon-Ho
2010

Speeding is known to be related to a significant portion of highway collisions. As part of the efforts to seek safety improvements of the California highway network, the California Department of Transportation (Caltrans) is exploring the implementation issues of automated speed enforcement (ASE). This report provides an overview of Task Order 6212 undertaken by California PATH to assess various issues associated with ASE systems.An ASE system designed for use in work zones was acquired and tested in several field experimental sites, along with several other commercially-off-the-shelf...

Transportation Modeling For The Environment

Barth, Matthew J.
Norbeck, Joseph M.
1994

In this report, the authors describe preliminary research dealing with vehicle emissions associated directly with 1) Automated Highway Systems ( AHS) and 2) ramp metering. In performing this analysis, a power-demand modal emissions model has been integrated with several transportation simulation models in order to quantitatively determine the effects of Intelligent Transportation Systems (ITS) technology on vehicle emissions. For AHS, a steady-state speed/emissions comparison has been conducted between vehicles that are platooned and non-platooned. A comparison has been made between a...

Platoon Collison Dynamics And Emergency Maneuvering III: Platoon Collison Models And Simulations

Tongue, Benson H.
Yang, Yean-tzong
1994

The purpose of this report is to document the development of a platoon collision model which can be used to study platoon collision dynamics under emergency situations. Based on previous studies, the vehicle model within the platoon is implemented with two bumpers which are developed to meet the realistic performance of a real bumper. Four control algorithms have been utilized to carry out the simulations.