Safety

Middleware for Cooperative Vehicle-Infrastructure Systems

Manasseh, Christian
Sengupta, Raja
2008

Middleware has emerged as an important architectural component in supporting distributed applications. The role of middleware is to present a unified programming model to application writers and to mask out problems of heterogeneity and distribution. Mobile sensors fall into the space of distributed systems that suffer from isolated data sources, heterogeneous communication infrastructure and varying application requirements. In this report, we provide a middleware architecture that addresses the needs of a distributed system made of mobile sensors in general and discuss the implementation...

Long Term Impacts of California’s Graduated Licensing Law of 1998

Cooper, Douglas
Gillen, David
2005

In July 1998 California changed its graduated driver licensing laws (GDL) for new drivers under the age of 18 to include restrictions on hours of driving, carrying teen-age passengers, and requiring more adult supervised driving practice. With fatal and injury crash data from California's Statewide Integrated Traffic Records System, this study, sponsored by Caltrans, used standard regression analysis as well as the Bai-Perron stochastic multiple structural break model to determine the effect of the law on teen-age passengers and crash rates of 16 year-old drivers. We found that in the four...

Collisions in Freeway Traffic: Influence of Downstream Queues and Interim Means to Address Them

Li, Zhibin
Chung, Koohong
Cassidy, Michael J.
2013

Findings from previous studies indicate that a freeway traffic collision is more likely to occur in close physical proximity to the tail of a queue. The implication is that collision likelihood increases when drivers abruptly alter their trajectories (e.g., by decelerating or changing lanes) on encountering the queue. The implication is supported and bolstered with new and detailed data that were painstakingly extracted from two freeway stretches in California. These data show how the likelihood of collision increases as both the spatial and the temporal proximities to the tail of an...

Weaving Analysis, Evaluation and Refinement

Skabardonis, Alexander
Kim, Amy
2010

Weaving sections are common design elements on freeway facilities such as near ramps and freeway to-freeway connectors. When the traffic demands exceed the capacity at weaving areas congestion may occur, which affects the operation of the entire freeway section. Traffic operational problems also may exist at weaving areas even when traffic demands are less than capacity because of the complexity of vehicle interactions, resulting in poor level of service (LOS) and potential safety problems. Existing procedures for the design and analysis of freeway weaving sections have several...

The Effects of Truck Driver Wages and Working Conditions on Highway Safety: A Case Study

Rodriguez, DA
Rocha, M
Khattak, AJ
Belzer, MH
2006

The role that human capital and occupational factors play in influencing driver safety outcomes has gained increased attention from trucking firms and policy-makers. This paper examines the role of these factors, in addition to demographic factors, in influencing crash frequency at the driver level. A unique driver-level dataset from a large truckload firm collected over a period of 26 months is used for estimating regression models of crash counts. Based on estimates from a zero inflated Poisson regression model, results suggest that human capital and occupational factors, such as...

Models of Vehicular Collision: Development and Simulation with Emphasison Safety II: On the Modeling of Collision between Vehicles in a Platoon System

O'reilly, Oliver M.
Et. al.
1997

In this report, an algorithm for the detection of collision between two vehicles is presented. The mechanical models used for the vehicles are based on the theory of a Cosscrat point. Here, we find it convenient to establish the corresponding models using the theory of a psuedo-rigid body. This theory facilitates the development of our collision-detection algorithm. The report concludes with four examples of vehicular impact scenarios in order to illustrate the applicability of the proposed algorithm.

Seamless Travel: Measuring Bicycle and Pedestrian Activity in San Diego County and its Relationship to Land Use, Transportation, Safety, and Facility Type

Jones, Michael G.
Ryan, Sherry
Donlon, Jennifer
Ledbetter, Lauren
Ragland, David R.
Arnold, Lindsay
2010

This paper provides the data collection and research results for the Seamless Travel project. The Seamless Travel Project is a research project funded by Caltrans and managed by the University of California Traffic Safety Center, with David Ragland, PhD., as the Principal Investigator and Michael Jones as the Project Manager. The project is funded by Caltrans Division of Innovation and Research and is being conducted by the Traffic Safety Center of University of California Berkeley and Alta Planning + Design.Measuring bicycle and pedestrian activity is a key element to achieving the goals...

Workzone Safety Improvements through Enhanced Warning Signal Devices

Christianson, Kent
Greenhouse, Daniel
Cohn, Theodore
Kim, Roy Young
Chow, Christina
2008

The high incidence of accidents associated with work zones suggests that current warning lights and signals have been in need of improvement. In this project we have developed and tested an improved emergency warning light intended specifically for Caltrans work zone vehicles, and an enhanced rear warning light for shadow trucks, both intended to improve visibility and conspicuity, and to reduce reaction times for drivers approaching the work zone.

Transient Aerodynamic Effects on a Four-Car Platoon During Passing Maneuvers: Data Summary

Tsuei, L.
Hedrick, J. K.
Savas, O.
1999

In order to provide reliable control algorithms on PATH automated highway system, knowledge of the transient aerodynamic forces is important from the point of the controlla- bility of the platoon and individual vehicles. In a passing maneuver, the platoon members may experience severe aerodynamic forces and yaw moment when another vehicle overtakes. Similar phenomenon can be seen in our daily life as one car passes the other but much more complicated flow field is expected when the interaction involves in a multi-vehicle platoon. It is the purpose of this study to quantify the unsteady...

Safety Performance and Robustness of Heavy Vehicle AVCS

Yih, Paul
Satyan, Krishna
Gerdes, J. Christian
2003

Commercial heavy vehicle research at the California Partners for Advanced Transit and Highways (PATH) program has focused on the development of controllers for partially to fully automated driving environments. Safe performance of Advanced Vehicle Control Systems (AVCS) must be demonstrated for a wide range of operating conditions and truck configurations to avoid any one of the many failure modes-such as rollover or jackknifing-common to articulated heavy vehicles. For this purpose, a multi-body dynamic model of a tractor semitrailer has been developed using a commercially available...