Traffic Operations and Management

Cooperative Intersection Collision Avoidance System (CICAS): Signalized Left Turn Assist and Traffic Signal Adaptation

Misener, Jim
Barnes, M.
Chan, Ching-Yao
Cody, Delphine
Dickey, Susan
Goodsell, R.
Gordon, Tim
Kim, Zu Whan
Kuhn, Tom
Lian, Thang
Nelson, David
Nowakowski, Christopher
Nubukawa, K.
Sharafsaleh, Ashkan
Shladover, Steven
Spring, John
VanderWerf, Joel
Zhang, Wei-Bin
Zhang, Liping
Zhou, Kun
2010

The Cooperative Intersection Collision Avoidance (CICAS) program is a multi-year, cooperative research program including federal, state, academic, and industry partners. The goal of the research program is to use ITS technologies to address the problem of intersection crashes. The program is funded through an 80/20 cost share, typically split between the U.S. Department of Transportation (D.O.T.) and a local state D.O.T. The program began in 2003, and has been divided into three functional segments based on crash type. The largest programmatic segment is CICAS-V (Violation) which is led by...

Regional Mobility Impacts Assessment of Highway Automation

Miller, Mark A.
Bresnock, Anne
Shladover, Steven E.
Lechner, Edward H.
Loannou, Petros A.
1997

Urban traffic congestion and air pollution are crucial issues in most metropolitan areas, but are more acute in Southern California than in most other North American regions. The PATH Program at the Institute of Transportation Studies, University of California, Berkeley and the Southern California Association of Governments (SCAG) have investigated some of the long-term regional impacts that could result from implementation of advanced highway technologies (automation and electrification) in the Los Angeles area. This chapter focuses on the evaluation of mobility impacts of highway...

Cooperative Adaptive Cruise Control in Real Traffic Situations

Milanés, Vicente
Shladover, Steven E.
Spring, John
Nowakowski, Christopher
Kawazoe, Hiroshi
Nakamura, Masahide
2014

Intelligent vehicle cooperation based on reliable communication systems contributes not only to reducing traffic accidents but also to improving traffic flow. Adaptive cruise control (ACC) systems can gain enhanced performance by adding vehicle–vehicle wireless communication to provide additional information to augment range sensor data, leading to cooperative ACC (CACC). This paper presents the design, development, implementation, and testing of a CACC system. It consists of two controllers, one to manage the approaching maneuver to the leading vehicle and the other to regulate car-...

Handling Cut-In Vehicles in Strings of Cooperative Adaptive Cruise Control Vehicles

Milanés, Vicente
Shladover, Steven E.
2016

Cooperative adaptive cruise control (CACC) systems are a candidate to improve highway capacity by shortening headways and attenuating traffic disturbances. Although encouraging results have been obtained until now, a wide range of traffic circumstances has to be investigated in order to get reliable CACC systems driving on real roads. Among them, handling both vehicle-to-vehicle (V2V) communications-equipped and unequipped vehicles merging into the string of CACC vehicles is a commonly mentioned challenge. In this article, an algorithm for managing the transitions in response to cut-ins...

Modeling Cooperative and Autonomous Adaptive Cruise Control Dynamic Responses Using Experimental Data

Milanés, Vicente
Shladover, Steven E.
2014

Vehicle longitudinal control systems such as (commercially available) autonomous Adaptive Cruise Control (ACC) and its more sophisticated variant Cooperative ACC (CACC) could potentially have significant impacts on traffic flow. Accurate models of the dynamic responses of both of these systems are needed to produce realistic predictions of their effects on highway capacity and traffic flow dynamics. This paper describes the development of models of both ACC and CACC control systems that are based on real experimental data. To this end, four production vehicles were equipped with a...

Influences on Energy Savings of Heavy Trucks Using Cooperative Adaptive Cruise Control

McAuliffe, Brian
Lammert, Michael
Lu, Xiao-Yun
Shladover, Steven
Surcel, Marius-Dorin
Kailas, Aravind
2018

An integrated adaptive cruise control (ACC) and cooperative ACC (CACC) was implemented and tested on three heavy-duty tractor-trailer trucks on a closed test track. The first truck was always in ACC mode, and the followers were in CACC mode using wireless vehicle-vehicle communication to augment their radar sensor data to enable safe and accurate vehicle following at short gaps. The fuel consumption for each truck in the CACC string was measured using the SAE J1321 procedure while travelling at 65 mph and loaded to a gross weight of 65,000 lb, demonstrating the effects of: inter-vehicle...

Development of an Analysis/Modeling/Simulation (AMS) Framework for V2I and Connected/Automated Vehicle Environment

Mahmassani, Hani S.
Elfar, Amr
Shladover, Steven E.
Huang, Zhitong
2018

This project developed a conceptual framework for an analysis, modeling, and simulation system for evaluating the impacts of connected and automated vehicle (CAV) technologies on transportation facilities at the strategic and operational levels, providing the basis for future development of CAV-enabled evaluation tools. The objective of this project is twofold: (1) to lay a foundational framework for the development of AMS system that includes connected and automated vehicles, and (2) to engage in small scale CAV AMS development using this framework that encourages future development...

Freeway Speed Harmonization

Ma, Jiaqi
Li, Xiaopeng
Shladover, Steven
Rakha, Hesham A.
Lu, Xiao-Yun
Jagannathan, Ramanujan
Dailey, Daniel J.
2016

In this paper, we present an overview and background on speed harmonization (SH). This paper reviews a number of representative studies that designed traffic control algorithms based on variable speed limits, ramp metering, connected vehicle, or automated vehicle for SH. We summarize fundamental mechanisms, control algorithms, and evaluation results of these studies. We investigate the opportunities brought by a portion of the vehicles communicating with each other using new technologies. We also investigate opportunities due to some vehicles having automated speed control. We discuss...

Applying Bundled Speed-Harmonization, Cooperative Adaptive Cruise Control, and Cooperative-Merge Applications to Managed-Lane Facilities

Ma, Jiaqi
Leslie, Ed
Ghiasi, Amir
Guo, Yi
Sethi, Sonika
Hale, David
Shladover, Steve
Lu, Xiao-Yun
Huang, Zhitong
2021

The purpose of this document is to describe the research, including simulations and a field experiment, involving the operation of connected and automated vehicles (CAVs) on managed lanes. The scenarios associated with this concept were chosen and designed to facilitate rapid and successful deployment of a solution that is not yet in use. The proposed operation involves deploying platoons of CAV-equipped vehicles that are governed by an integrated set of speed-harmonization, cooperative-merge, and cooperative-adaptive-cruise-control (CACC) applications. The concept accounts for CACC-...

Novel Freeway Traffic Control with Variable Speed Limit and Coordinated Ramp Metering

Lu, Xiao-Yun
Varaiya, Pravin
Horowitz, Roberto
Su, Dongyan
Shladover, Steven E.
2011

Freeway corridor traffic flow is limited by bottleneck flow. If the section upstream of a bottleneck is congested, the bottleneck flow will drop well below its capacity. A logical approach to maximizing recurrent bottleneck flow is to create a discharge section immediately upstream of the bottleneck. This paper proposes a control strategy for combining variable speed limits (VSL) and coordinated ramp metering (CRM) design to achieve this objective when the bottleneck can be represented as a lane (or virtual lane) reduction. At each time step, VSL is designed first, with mainline flow, on-...