Connected and Automated Vehicles

Safety and Efficiency Tradeoff Analysis for Automated Highway System: Part 3: Longitudinal Separation on AHS: A Trade-off Between Collision Probability/Severity and Capacity

Tsao, H.-S. Jacob
Hall, Randolph W.
1997

This report develops a probabilistic model for analyzing longitudinal collision/safety between an abruptly decelerating vehicle and its immediate follower on an Automated Highway System. The input parameters are the distance between the two vehicles, their common speed prior to the failure, the reaction delay of the following vehicle and a bivariate distribution for the two deceleration rates. The output includes the probability of a collision and the probability distribution of the relative speed at collision time. These safety consequences can be used to balance the desire to increase...

Modeling of the Brake Line Pressure to Tire Brake Force Subsystem

Xu, Z.
Ioannou, P.
1994

One of the most challenging problems in automated vehicle control is when and how to apply the brakes. In order to deal with such a problem, a good understanding of the dynamical behavior of the braking mechanism is essential. In this report we use experimental data from a series of tests performed in collaboration with Ford research engineers to modelthe brake line pressure to tire brake force subsystem. This model will be used together with that of the master cylinder to line pressure currently under study, for developing an overall model for the braking mechanism. The brake model will...

A Conceptual Approach for Developing and Analyzing Alternate Evolutionary Deployment Strategies for Intelligent Vehicle/Highway Systems

Al-Ayat, Rokaya
Hall, Randolph
1994

Intelligent Vehicle Highway Systems (IVHS) comprise a spectrum of technologies, with both short - term and long - term applications. Eventually, deployment of IVHS may lead to fully automated, hands-off and feet-off, driving. In the short - term, IVHS has included traffic control systems, in - vehicle information systems, and a range of new roadway sensors.This paper develops a framework for planning the evolutionary deployment of IVHS technologies. It defines an evolutionary deployment sequence, identifies baseline assumptions, and presents strategies for achieving success. This paper...

Evaluation Of Work Crew And Highway Hazard Conspicuity

Misener, Jim
1998

The report quantitatively addresses conspicuity of highway features, particularly in work zones, from the perspective of driver detection and driver decision making. The study focuses on evaluating the detection process, selecting and exercising human perception-acquisition models suitable for quick running and larger scale microsimulations to evaluate system effectiveness of pre-Automated Highway System (AHS) driver-assist systems. The report describes this process and provides a detection example of a driver-assist collision avoidance model.

A Network Layer for Intelligent Vehicle Highway Systems

Eskafi, Farokh
Zandonadi, Marco
1999

The objective of this paper is to design the network layer of a communication stack to be used in Automated Highway Systems (AHS). The communication model we propose allows cars to form private subnets, the configuration of which can change dynamically. Each car be part of multiple subnets and can send broadcast, multicast and point-to-point messages to other vehicles (both on the same subnet and on others, through a routing mechanism). Each subnet is managed by a server: a car that is in charge of accepting/rejecting join requests and of keeping a consistent state within the subnet....

Robust Automatic Steering Control for Look-Down Reference Systems with Front and Rear Sensors

Guldner, Jurgen
Sienel, Wolfgang
Tan, Han-Shue
Ackerman, Jurgen
Patwardhan, Satyajit
Bunte, Tilman
1997

This paper describes a robust control design for automatic steering of passenger cars. Previous studies [l-3] showed that' reliable automatic driving at highway speed may not be achieved under practical conditions with look-down reference systems which use only one sensor at the front bumper to measure the lateral displacement of the vehicle from the lane reference. An additional lateral displacement. sensor is added here at the tail bumper to solve the automatic steering control problem. The control design is performed stepwise: First, an initial controller is determined using the...

Simulating Life with Personally-Owned Autonomous Vehicles through a Naturalistic Experiment with Personal Drivers

Harb, Mustapha, PhD
Malik, Jai, PhD
Circella, Giovanni, PhD
Walker, Joan L., PhD
2022

Forty-three households in the Sacramento region representing diverse demographics, modal preferences, mobility barriers, and weekly vehicle miles traveled (VMT) were provided personal chauffeurs for one or two weeks to simulate travel behavior with a personally-owned, fully autonomous vehicle (AV). During the chauffeur week(s), the total number of trips increased on average by 25 percent, 85 percent of which were “zero-occupancy” (ZOV) trips (when the chauffeur is the only occupant). Average VMT for all households increased by 60 percent, over half of which came from ZOV trips. VMT...

Synthesis of State-Level Planning and Strategic Actions on Automated Vehicles: Lessons and Policy Guidance for California

Wong, Stephen
Shaheen, Susan, PhD
2020

This synthesis provides a summary and comparative analysis of actions states across the United States are taking inresponse to automated vehicles (AVs). The research focuses on state-level stakeholder forums (e.g., task forces, committees) and state-level strategic actions (e.g., studies, initiatives, programs) initiated by a state legislature, agovernor, or a state agency. The analysis found that AV stakeholder forums and strategic actions address a diverse set offocus areas, but they pay minimal attention to the implications of AVs on the environment, public health, social equity, land...

Using Automated Vehicle (AV) Technology to Smooth Traffic Flow and Reduce Greenhouse Gas Emissions

Almatrudi, Sulaiman
Parvate, Kanaad
Rothchild, Daniel
Vijay, Upadhi
2022

Passenger and heavy-duty vehicles make up 36% of California’s greenhouse gas (GHG) emissions. Reducing emissions from vehicular travel is therefore paramount for any path towards carbon neutrality. Efforts to reduce GHGs by encouraging mode shift or increasing vehicle efficiency are, and will continue to be, a critical part of decarbonizing the transportation sector. Emerging technologies are creating an opportunity to reduce GHGs. Human driving behaviors in congested traffic have been shown to create stop-and-go waves. When waves form, cars periodically slow down (sometimes to a stop) and...

“Don’t Keep Us Out of the Revolution!”: Accessibility and Autonomous Rideshare in California

Heuser, Katie L.
2024

Robotaxi services, or rideshare operated by autonomous vehicles, present an opportunity for independent and convenient transportation for people with disabilities. The proliferation of robotaxis in California has been met with mixed reactions from the disability community. To better understand perceptions of and expectations for robotaxis, this report uses semi-structured interviews with representatives from disability advocacy organizations. For many people with disabilities, especially for people with intellectual, developmental, and/or physical disabilities, robotaxis are inaccessible....