Safety

Emergency Vehicle Maneuvers and Control Laws for Automated Highway Systems

Toy, Charmaine
Leung, Kevin
Alvarez, Luis
Horowitz, Roberto
2001

In this report control laws and maneuvers for high priority emergency vehicle transit on automated highways are presented. The work presented is specifically designed for use with the Partners for Automated Transit and Highways (PATH) hierarchical control architecture. The types of control laws that are needed for the different hierarchical layers are examined, and specific maneuvers for the coordination and link layers are presented. Simulations using SmartCAP (a mesoscopic traffic simulator) and SmartAHS (a microscopic traffic simulator) demonstrate the maneuvers' functionality.

A Specification Of An Automated Freeway With Vehicle-borne Intelligence

Hitchcock, Anthony
1992

The focus of this work is to derive a technique of safety analysis for an automated freeway system. To demonstrate the method of safety analysis a procedure called fault tree analysis is applied. The specified freeway operates with vehicles in platoons. The safety criterion used here is that two or more simultaneous faults must occur independently before the hazards can arise.

Safety and Throughput Analysis of Automated Highway Systems

Godbole, Datta N.
Lygeros, John
2000

We investigate the effect of a number of design alternatives on the safety and capacity of an Automated Highway System. Our methodology makes use of two computational tools, designed to highlight the fundamental limitations of the vehicle dynamics, sensing and control strategies and inter-vehicle communication. The first tool produces the minimum spacing necessary for two vehicles not to collide, as a function of their state and capabilities. The second tool investigates the multiple collisions that may occur in a string of vehicles if the spacing requirements of the first tool are...

A Comparative Safety Study of Limited versus Continuous Access High Occupancy Vehicle (HOV) Facilities

Jang, Kitae, MS
Ragland, David R., PhD
Chan, Ching-Yao, PhD
2009

The report summarizes the findings from comparative studies of safety performance between two different types of High Occupancy Vehicle (HOV) facilities in California - continuous access versus limited access. The findings show that HOV facilities with limited access offer no safety advantages over those with continuous access, whether measured by percentage of collisions, collisions per mile, collisions per VMT, or collision severity. As part of the present research, the authors investigated the relationship between HOV design features and safety performance of HOV facilities. One key...

Who Noticed, Who Cares? Passenger Reactions to Transit Safety Measures

Wallace, RR
Rodriguez, DA
White, C
Levine, J
1999

Safety and security are important considerations for the transit operator, but few empirical studies exist that measure the effectiveness of measures taken to improve transit safety either on actual crime (or other incident) data or transit passengers’ perceived safety. The current study focuses on the links between transit safety measures implemented in the Ann Arbor, Michigan, area; the visibility of these improvements to transit passengers; and perceived levels of safety. The findings indicate that the characteristics of passengers’ riding patterns, and whether a safety measure...

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority: Passenger Reactions to Transit Safety Measures

Wallace, RR
Rodriguez, D
White, C
Levine, J
1999
Safety and security are important considerations for the transit operator, but few empirical studies exist that measure the effectiveness of measures taken to improve transit safety on either actual crime (or other incident) data or transit passengers’ perceived safety. The current study focuses on the links between transit safety measures implemented in the Ann Arbor, Michigan region, the visibility of these improvements to transit passengers, and perceived ...

SmartAHS and SHIFT Enhancements, Persistence and Query Interpretation

Misener, Jim
2000

We have enhanced and "tuned" SmartAHS and SHIFT to address a wide variety of functional and user needs. SmartAHS has become an important microsimulation tool for design, analysis and evaluation of AHS - and "pre-AHS" or AHS deployment - concepts and scenarios in dimensions of system performance (i.e., throughput and travel time), safety and comfort. The SmartAHS/Hybrid Systems Tools Interface Format (SHIFT) is the basis for SmartAHS, and it is the general hybrid systems simulator for user-defined AHS architectures.

Relationships Among Urban Freeway Accidents, Traffic Flow, Weather, and Lighting Conditions

Golob, Thomas F.
Recker, Wilfred W.
2003

Linear and nonlinear multivariate statistical analyses are applied to determine how the types of accidents that occur on heavily used freeways in Southern California are related both to the flow of traffic and to weather and ambient lighting conditions. Traffic flow is measured in terms of time series of 30-second observations from inductive loop detectors in the vicinity of the accident prior to the time of its occurrence. Results indicate that the type of collision is strongly related to median traffic speed and to temporal variations in speed in the left and interior lanes. Hit-object...

Evaluation Of The Advanced Operating System Of The Ann Arbor Transportation Authority: Impacts of an Advanced Public Transportation System: Demonstration Project

Levine, J
Hong, Q
Hug, GE
Rodriguez, D
1999
In 1997, the Ann Arbor (Michigan) Transportation Authority began deploying a set of integrated advanced public transportation system technologies in its vehicles, stations and control center. This paper summarizes selected findings of a multidimensional evaluation of the effects of the system on schedule adherence and transfer time, passenger perception and impacts on drivers. Some improvement in on-time performance was observed in vehicle departures from major ...

Commercial Vehicle Parking in California: Exploratory Evaluation of the Problem and Solutions

Rodier, Caroline J., PhD
Shaheen, Susan A., PhD
Allen, Denise M.
Dix, Brenda
2010

California is home to major international ports in Long Beach, Los Angeles, and Oakland, as well as the second largest border crossing between Mexico and the U.S. California’s highways are critical commercial links from these ports of entry to the nation and carry more commercial vehicle truck traffic than any other state in the U.S. Given the high volume of truck travel in California, it is not surprising that there is a serious shortage of truck parking in the state. This shortage negatively impacts economic productivity, roadway safety, air quality, and public health. This report begins...