Safety

Augmented Speed Enforcement Project at UC Berkeley

Chan, Ching-Yao
Gupta, Somak Datta
Huang, Jihua
Chiu, Guan-Ling
Nelson, David
Lian, Thang
2013

This report describes the development of an automated speed enforcement (aSE) system. The main function of the aSE system is to communicate relevant speed, violation, and hazard information to the stakeholders in the work zone context: drivers, CHP officers, and workers. The system consists of two sub-systems that can work jointly in an integrated manner as a whole but they can also be deployed and tested separately.

Develop Methods to Reduce or Prevent Backing Crashes

Cooper, Douglas L.
Duffy, Sarah
Orrick, Phyllis
Ragland, David R.
2010

Workplace motor vehicle incidents at Caltrans are a significant cause of injuries, employee lost time, and property damage. Because backing crashes are major contributors to motor vehicle incidents, identifying and promoting methods of reducing backing accidents is a top priority. According to internal Caltrans’ data, 92.3% of workplace backing crashes were preventable by the driver. Backing crashes are the single largest category of preventable crashes, representing 30% of preventable crashes in the Caltrans fleet. From 1998 through 2007, preventable backing crashes cost Caltrans at least...

A Multi-channel VANET Providing Concurrent Safety and Commercial Services

Mak, Tony K.
Laberteaux, Kenneth P.
Sengupta, Raja
2005

One of the key goals of a vehicular ad-hoc network (VANET) is providing sufficient quality of service (QoS) for real-time safety applications while concurrently supporting commercial services. This paper proposes a multi-channel wireless communication architecture and protocol for the scenario where commercial services are provided by roadside infrastructure. This solution extends the IEEE 802.11 wireless LAN protocol to schedule periodic safety messages in a "safety channel". It explicitly supports concurrent non-time-critical communications in separate, non-safety "service channels"....

Simulation and Animation Tools for Analysis of Vehicle Collision: SMAC (Simulation Model of Automobile Collisions) and Carmma (Simulation Animations)

Hongola, Bruce
Chan, Ching-Yao
1999

This document describes part of the work conducted under MOU324, related to the studies of vehicle collisions in vehicle-following operations. The goal of the study is to conduct vehicle dynamics and control analysis and to explore display methods so that analytical results can be visualized. This working paper is a description of the functional capabilities of a series of computer programs that can be used to investigate the consequences of vehicle collisions. The core element of the simulation tools for vehicle collision dynamics is SMAC (Simulation Model of Automobile Collisions)...

Brake Dynamics Effect On IVHSLane Capacity

Maciua, Dragos B.
1994

This paper attempts to assess the effects of brake system dynamics and inter-vehicle communication delays (microscopic characteristics) on the capacity of an automated highway system (macroscopic characteristics). Simulations were conducted to investigate the relationship between the microscopic and macroscopic characteristics. Recommendations are made regarding the maximum desired delays, intra-platoon and inter-platoon distances and platoon size in order to achieve the highest possible capacity while maintaining a high degree of safety.

A Focus Group Study of Automated Highway Systems and Related Technologies

Yim, Youngbin
1997

The paper presents the findings of a focus group study of the automated highway system and its related technologies, specifically adaptive cruise control and collision avoidance systems, in the San Francisco Bay Area. A majority of the participants had a favorable reaction to AHS despite the fact that almost all were concerned about its safety and funding capability. Responses to the adaptive cruise control were generally positive. The focus group participants recognized the safety benefits, the convenience, and especially the stress reduction of using the automated highway system, when...

Effect of Longitudinal Control on Capacity

Beji, Yousser
1987

This paper focuses on what benefits a longitudinal control system can be expected to render to the present highway system.There are three major reasons why longitudinal control should be expected to improve traffic flow and to reduce accidents.(1) It may permit higher traffic densities with uniform spacing forming an even distribution with increased travel speeds and consequently higher capacity.(2) It may reduce the rate of rear-end collisions that occur on urban freeways.(3) It can provide increased stability in traffic flow (shockwaves due to human response characteristics are the main...

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.