Steven E. Shladover

• University of California, Berkeley

As driverless automated driving systems (ADS) start to operate on public roads, there is an urgent need to understand how safely these systems are managing real-world traffic conditions. With data from the California Public Utilities Commission (CPUC) becoming available for Transportation Network Companies (TNCs) operating in California with and wi...

In 2022, the Automated Road Transportation Symposium returned to a traditional face-to-face meeting format after two years of virtual meetings caused by the global pandemic. The plenary presentations and breakout discussions continued to provide the meeting participants with the most up-to-date and authoritative information about the current intern...

In 2021, the Automated Vehicles Symposium was succeeded by the Automated Road Transportation Symposium (ARTS21), which was produced entirely by the Transportation Research Board. With the continuing disruptions from the global pandemic, it was again produced as a virtual online meeting. The plenary presentations and breakout discussions continued t...

Automated driving has attracted intense attention in the media and among the general public, based on extremely optimistic predictions from some industry participants, but these have started to become more realistic in the last couple of years, after the “hype cycle” for automation peaked. This paper explains the opportunities for Automated Driving...

The 2020 Automated Vehicles Symposium represented a significant departure from its predecessors, since it had to be converted on short notice from an in-person meeting to a virtual meeting in response to the global COVID-19 pandemic. Most of the originally planned content was retained in the process, although the activities were of necessity less i...

Cooperative Adaptive Cruise Control (CACC), as an advanced version of adaptive cruise control (ACC), automates brake and engine controls based on the information received from wireless V2V communications and remote sensors, enabling smaller vehicle-following time gaps. It can improve the safety of vehicle platooning and increase fuel savings. As an...

The development of Connected Automated Vehicle (CAV) technology introduces vehicle connectivity and automation into urban intersection management. It offers powerful means for accurate traffic state perception and effective traffic control actuation. This enabled the development of an intersection control algorithm that included an optimal traffic...

This paper provides an introduction to the opportunities for improving the performance of road transportation automation systems by use of vehicle-vehicle and vehicle-infrastructure communication and cooperation. Four different types of cooperative driving automation are defined and examples of the functionality enabled by each are described. Altho...

The 2019 Automated Vehicles Symposium followed a similar pattern to its predecessors, but with a change of location from California to Orlando, Florida, to offer a different local perspective. The plenary and poster presentations and breakout discussions continued to provide the meeting participants with the most up-to-date and authoritative inform...

Cooperative adaptive cruise control (CACC) vehicle string operations have the potential to improve significantly the mobility and energy consumption performance of congested freeway corridors. This study examines the impact of CACC string operations on vehicle speed and fuel economy on the 13-mi SR-99 corridor, near Sacramento, CA. It extends the e...

Quantifying the effect of Cooperative Adaptive Cruise Control (CACC) on traffic mobility and vehicle fuel consumption has been a challenge because it requires a modeling framework that depicts the interactions among manually driven vehicles and CACC vehicles in the complex multilane traffic stream. This study adopted a state-of-the-art traffic flow...

Connected and automated vehicles (CAVs) have the potential to address a number of safety, mobility, and sustainability issues of our current transportation systems. Cooperative longitudinal motion control is one of the key CAV technologies that allows vehicles to be driven in a cooperative manner to achieve system-wide benefits. In this paper, we p...

Cooperative signal control algorithm Intersection throughput Vehicle fuel consumption CACC string operation A B S T R A C T Vehicles equipped with Cooperative Adaptive Cruise Control (CACC) have the capability to broadcast their real-time speed and location information via wireless communications. They can also safely operate in multi-vehicle strin...

The 2018 Automated Vehicles Symposium built on the successes of the predecessor meetings, with an even larger and more diverse roster of participants and a broader selection of breakout sessions. The plenary and poster presentations and breakout discussions continued to provide the meeting participants with the most up-to-date and authoritative inf...

This paper presents quantitative driving performance results for a cooperative adaptive cruise control (CACC) system tested on Class-8 trucks. It focuses on the vehicle following control performance measured on a closed test track and in mixed traffic on public freeways. The speed and distance tracking errors are reported for the string of three tr...

Realistic microscopic traffic simulation is essential for prospective evaluation of the potential impacts of new traffic control strategies. Freeway corridors with interacting bottlenecks and dedicated lanes generate complex traffic flow phenomena and congestion patterns, which are difficult to reproduce with existing microscopic simulation models....

Cooperative Adaptive Cruise Control (CACC) is a Connected Automated Vehicle (CAV) system that has potential to significantly improve the traffic flow of arterial networks. Successful implementation of the system relies on the efficient operation of CACC vehicle strings at intersections. To this end, we have developed a cooperative traffic control a...

Based on the outcomes from the automated trucking breakout session at the 2017 Automated Vehicles Symposium, this Chapter reviews the current state-of-the-art of automated trucking applications and discusses key factors expected to influence their deployment. It is suggested that a key challenge for the deployment of automation in the trucking doma...

The 2017 Automated Vehicles Symposium built on the successes of the predecessor meetings, with an even larger and more diverse roster of participants and a broader selection of breakout sessions. The plenary and poster presentations and breakout discussions continued to provide the meeting participants with the most up-to-date and authoritative inf...

Modeling impacts of Cooperative Adaptive Cruise Control (CACC) on multi-lane freeway traffic can be challenging. It requires an accurate description of the formation and disengagement of CACC vehicle strings when CACC vehicles are mixed with manually driven vehicles in the traffic stream. It also needs to depict the behaviors of CACC vehicles under...

Cooperative adaptive cruise control (CACC) systems have the potential to improve traffic flow and fuel efficiency, but these effects are challenging to estimate. This paper reports the development of a micro-simulation model to represent these impacts for heavy trucks using CACC when they share a freeway with manually driven passenger cars. The sim...

Cooperative adaptive cruise control (CACC) is a driver-assist technology that uses vehicle-to-vehicle wireless communication to realize faster braking responses in following vehicles and shorter headways compared with adaptive cruise control. This technology not only enhances road safety, but also offers fuel savings benefits as a result of reduced...

The 2016 Automated Vehicles Symposium built on the successes of the predecessor meetings, with an even larger and more diverse roster of participants and a broader selection of breakout sessions. The plenary and poster presentations and breakout discussions continued to provide the meeting participants with the most up-to-date and authoritative inf...

Cooperative Adaptive Cruise Control (CACC) allows vehicles to exchange real-time operational information wirelessly, enabling vehicles to travel in strings with shorter than normal time gaps between adjacent vehicles and ultimately increasing the freeway capacity. This study is intended to investigate the impact of CACC vehicle string operation on...

Cooperative driving is based on wireless communications between vehicles and between vehicles and roadside infrastructure, aiming for increased traffic flow and traffic safety, while decreasing fuel consumption and emissions. To support and accelerate the introduction of cooperative vehicles in everyday traffic, in 2011, nine international teams jo...

Cooperative adaptive cruise control (CACC) systems have the potential to improve traffic flow and energy consumption efficiency, but these effects are challenging to estimate. This report presents the development of a micro-simulation model to represent these impacts for heavy trucks using CACC when they share a freeway with manually driven passeng...

Cooperative Adaptive Cruise Control (CACC) is a driver assist technology that uses vehicle-to-vehicle wireless communication to realize faster braking responses in following vehicles and shorter headways compared to Adaptive Cruise Control (ACC). This not only enhances road safety, but also offers fuel savings benefits as a result of reduced aerody...

Cooperative Adaptive Cruise Control (CACC) allows vehicles to exchange real-time operational information wirelessly, enabling vehicles to travel in strings with shorter than normal time gaps between adjacent vehicles and ultimately increases the freeway capacity. This study is intended to investigate the impact of CACC vehicle string operation on t...

CACC operation strategies are important for the successful deployment of CACC by improving the probability for CACC vehicles to join CACC strings, and help maintain the string operation throughout a highway corridor. To quantify the traffic impacts of CACC when various CACC operation strategies are implemented, we have developed a micro-simulation...

Realistic microscopic traffic simulation is essential for prospective evaluation of the potential impacts of new traffic control strategies. Freeway corridors with interacting bottlenecks and dedicated lanes generate complex traffic flow phenomena and congestion patterns, which are difficult to reproduce with existing microscopic simulation package...

Cooperative adaptive cruise control (CACC) systems have the potential to improve traffic flow and fuel efficiency, but these effects are challenging to estimate. This paper reports the development of a micro-simulation model to represent these impacts for heavy trucks using CACC when they share a freeway with manually driven passenger cars. The sim...

The development of automated driving systems presents a special challenge to the existing regulatory regimes for road vehicles. Automated driving systems shift the responsibility for roadway and traffic monitoring, decision making, and vehicle control from the driver to the automated driving system, which will necessitate a shift of the responsibil...

This paper provides an introduction to the history and concepts of connected and automated vehicle systems. Connected vehicle (CV) systems have been an important focal point for the intelligent transportation systems program for a while already, based on their ability to support a wide range of ITS applications and to knit vehicles and infrastructu...

High Occupancy Vehicle (HOV) lanes are expected to mitigate traffic congestion by reducing the use of single-occupancy vehicles. However, implementing HOV lanes generates dynamic interactions between HOV lanes and general purpose lanes and inconsistent findings have been reported regarding the impact of HOV lanes on traffic operations. This paper p...

Modelling detailed microscopic level interactions among classes of vehicles with varying levels of automation and connectivity is essential for evaluating the potential impact or benefit of ACC (Adaptive Cruise Control) and CACC (Cooperative ACC). This requires developing a driving behavior model that is applicable to human-driven vehicles, as well...

Despite the prevalent discussions on automated vehicles, little research has been conducted with a focus on inclusiveness of traditionally excluded populations from driving. Even though we may envision a future where everyone can drive with perfect automation, the problem will not be that simple. As with any other problem domains, we need to scruti...

This paper presents two cooperative automated merging strategies for highway entry, one using I2V communication and the other one using V2V communication. For each communication architecture, a simple but effective algorithm is proposed. The proposed automated merge strategies are compared with a benchmark manual driving model in a traffic micro-si...

Ubiquitous, commercial deployment of automated road vehicles is desirable in order to realize their potential benefits such as crash avoidance, congestion mitigation, reduced environment impact, reduced driver stress, and increased driver productivity. A rigorous application of systems engineering, which includes validation and verification as cruc...

The 2015 Automated Vehicles Symposium built on the successes of the predecessor meetings, with an even larger and more diverse roster of participants and a broader selection of breakout sessions. It was organized in cooperation with the University of Michigan’s Mobility Transformation Center, which provided an opportunity for the Symposium particip...

They are coming, but not the way you may have been led to think

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 (VSL), ramp metering (RM), connected vehicle (CV) or automated vehicle (AV) for SH. We summarize fundamental mechanisms, control algorithms, an...

Technical studies on automated driving of passenger cars were started in the 1950s, but those on heavy trucks were started in the mid-1990s, and only a few projects have dealt with truck automation, which include “Chauffeur” within the EU project T-TAP from the mid-1990s, truck automation by California PATH from around 2000, “KONVOI” in Germany fro...

Automated driving systems (ADSs) present several challenges to the existing regulatory framework for road vehicles at both the national and the state level. NHTSA has been primarily responsible for automotive safety, and states have been responsible for the regulations that govern vehicle registration and the training, evaluation, and licensing of...

Cooperative adaptive cruise control (CACC) has been loosely defined in recent literature to represent a wide variety of vehicle-following control concepts, and when trucks are discussed, CACC is often used synonymously with platooning. This paper discusses the similarities and differences between CACC and platooning and provides a more precise func...

Although passenger car automation has captured the public's attention in recent years, heavy truck automation has also been a major research topic around the world. In the U.S., the California PATH program at U.C. Berkeley has been engaged in heavy vehicle driver assistance and automation research for trucks, buses, and snow removal equipment for o...

This chapter introduces the Automated Vehicles Symposium 2014 (AVS14), which was the original source for the papers that are included in this volume. The structure and organization of the meeting are explained, describing its mixture of plenary talks, breakout discussions, technical demonstrations and ancillary meetings. The chapter concludes with...

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, h...

Cooperative Adaptive Cruise Control (CACC) includes multiple concepts of communicationenabled vehicle following and speed control. This paper presents definitions and classifications to help clarify the distinctions among different types of automatic vehicle following control that are often conflated with each other. A distinction is made between V...

Design and implement CACC system on three Volvo trucks based on Volvo commercial ACC, Volvo experience in SARTRE, and PATH platoon projects Perform human factors research with truck drivers Driving simulator tests to design human-machine interface On-road tests to determine following distance preferences Test energy efficiency at time gap ranges ch...

Higher levels of road vehicle automation pose a regulatory challenge in the United States. At the national level, NHTSA has been responsible for ensuring vehicle safety through the mandatory Federal Motor Vehicle Safety Standards and the voluntary New Car Assessment Program. Although NHTSA typically regulates the technology aspects of vehicle safet...

Cooperative adaptive cruise control (CACC) includes multiple concepts of communication-enabled vehicle following and speed control. Definitions and classifications are presented to help clarify the distinctions between types of automated vehicle-following control that are often conflated with each other. A distinction is made between vehicle-to-veh...

Most previous algorithms for variable speed limit and variable speed advisory (VSL-VSA) for bottleneck flow maximization are local and occupancy measurement-based. Some algorithms for freeway networks with multiple bottlenecks were proposed on the basis of the second-order METANET model, but these were rather complicated. This paper proposes (a) a...

Previous studies on variable speed limits (VSLs) were reviewed. These studies were classified as three types: simulations for algorithm development and evaluations, VSL implementation and field testing, and a combination of VSLs with ramp metering. The review considered strategies and algorithms, targeted traffic improvements (safety, throughput, e...

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 ef...

Vehicle automation has been one of the fundamental applications within the field of intelligent transportation systems (ITS) since the start of ITS research in the mid-1980s. For most of this time, it has been generally viewed as a futuristic concept that is not close to being ready for deployment. However, recent development of “self-driving” cars...

This chapter presents the results of experiments on coordinated automatic longitudinal control of a platoon of three Class 8 tractor-trailer trucks, using 5.9 GHz DSRC with 100 ms update intervals for coordination. The trucks were tested not only in constant-speed cruising conditions, but also through acceleration and deceleration profiles, up and...

This chapter presents the results of experiments on coordinated automatic longitudinal control of a platoon of three Class 8 tractor-trailer trucks, using 5.9 GHz DSRC with 100 ms update intervals for coordination. The trucks were tested not only in constant-speed cruising conditions, but also through acceleration and deceleration profiles, up and...

This chapter introduces the TRB 2013 Workshop on Road Vehicle Automation, which was the original source for the papers that are included in this volume. The TRB organization and its functions are explained, providing the context for this workshop and its significance. The reasons for creating the workshop are explained, in the context of the histor...

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...

Previous studies on Variable Speed Limits (VSL) have been reviewed. They are classified as three types: simulations for algorithm development and evaluations, VSL implementation and field testing, and combination of VSL with RM (Ramp Metering). The review has considered strategies and algorithms, targeted traffic improvements (safety and/or through...

Recent media coverage has created the impression that the technical challenges for fully automated driving systems are largely solved and that the primary impediments to widespread deployment of such systems are legal, institutional and customer acceptance issues. This paper explains the severity of the technical challenges that are not close to be...

With the emergence of connected vehicle technology, the use of probe trajectory data to estimate queue length has recently received considerable attention. Unlike data collected by loop detectors, probe trajectory data can provide a lower bound on the queue length even if the market penetration rate is low. An event-based method is developed: it us...

With the emergence of connected vehicle technology, the use of probe trajectory data to estimate queue length has recently received considerable attention. Unlike data collected by loop detectors, probe trajectory data can provide a lower bound on the queue length even if the market penetration rate is low. An event-based method is developed: it us...

The seven papers in this special section contains the contributions of teams that participated in the 2011 Grand Cooperative Driving Challenge (GCDC) that was organized by The Netherlands Organization for Applied Scientific Research TNO and the Dutch High Tech Automotive Systems innovation program (HTAS).

This paper describes the use of microscopic simulation to estimate the effect of varying market penetrations of adaptive cruise control (ACC) and cooperative adaptive cruise control (CACC) on highway capacity. The distribution of time gap settings that drivers from the general public used in a real field experiment were used in the simulation, maki...

This paper presents an overview of current projects that deal with vehicle platooning. The platooning concept can be defined as a collection of vehicles that travel together, actively coordinated in formation. Some expected advantages of platooning include increased fuel and traffic efficiency, safety and driver comfort. There are many variations o...

This study used microscopic simulation to estimate the effect on highway capacity of varying market penetrations of vehicles with adaptive cruise control (ACC) and cooperative adaptive cruise control (CACC). Because the simulation used the distribution of time gap settings that drivers from the general public used in a real field experiment, this s...

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 combi...

The timing of traffic signals is rarely determined by the needs of bicyclists, in part because quantitative data about the timing of intersection crossing maneuvers by bicyclists have not generally been available. This study built on a video image-processing method developed and reported in a previous study to collect data at five new intersections...

The impending widespread availability of realtime traffic condition data from vehicles serving as traffic probes offers the possibility of significant advances in traffic signal control performance. In order to realize these advances, it is necessary to understand the capabilities and limitations of traffic probe data collection. In this paper, veh...

The METANET model, deduced based on equilibrium state assumption, provides a candidate model for freeway traffic control design since it has both speed and density dynamics, but the previous work parameterized the speed control variable to be highly nonlinear, which caused difficulty in control design and implementation. Besides, the model could no...

Cooperative adaptive cruise control (CACC) enables drivers to follow each other at shorter gaps than autonomous ACC, and our recent field test demonstrated that drivers are favorably inclined toward using those shorter gaps. In this paper, we simulate multi-lane highway traffic conditions with a variety of combinations of conventional manual drivin...

In this paper, we describe a framework and system architecture for sharing of information between vehicles and infrastructure with the aim of increasing intersection safety. Emerging intersection safety applications are based on location sensing and wireless communication. We show that these applications can only be realized if vehicles and interse...

ITS systems can help reduce CO₂ emissions in three different ways, which need to be evaluated using different modeling paradigms. The ITS systems that reduce demand for vehicle travel should be analyzed using regional transportation planning models that explicitly represent modal choice and pricing sensitivity of travel choices. The ITS...

Weaving effect might form a bottleneck on freeway and cause congestion. Traditional ramp metering may not be sufficient to control the traffic in this case to a satisfoctory state. Combining ramp metering and Variable Speed Limit (VSL) control may be an option. This paper first calibrates Gipps's car-following model using NGSIM data, and then intro...

Vehicle-to-vehicle (V2V) cooperative systems that alert drivers to road- way hazards are increasingly being studied to improve freeway safety and should be implemented by automakers in the near future. However, the impact of these systems on traffic operations has not been assessed. A methodology is described for modeling driver response to lane-bl...

Density, speed, and flow are the three critical parameters for traffic analysis. High-performance traffic management and control require the estimation prediction of space mean speed and density for large spatial and temporal coverage. Speed, including spot mean speed and space mean speed, and flow estimation are relatively easy to measure and esti...

Freeway corridor traffic flow is limited by bottleneck flow. A possible approach for 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...

Currently, Adaptive Cruise Control (ACC) systems can automate vehicle speed control to maintain following time-gaps in the range of one to two seconds. In this study, a field test was conducted to determine whether or not drivers would be comfortable with the sub-second following time-gaps that could be provided by a Cooperative ACC (CACC) system....

This paper proposes a control strategy for combining Variable Speed Limits (VSL) and Ramp Metering (RM) to maximize the flow of a recurrent bottleneck which can be modeled as a lane reduction. The control strategy can be simply described as: (a) Assuming a known ramp metering rate for each onramp; (b) using Finite Time Horizon Model Predictive Cont...

This paper defines a comprehensive range of operational concepts for automating the driving of heavy trucks. These concepts are defined in terms of the amount of driving functionality that is transferred from the driver to the automated system and the roadway conditions in which the trucks would operate. With the minimum amount of automation (provi...

The 13 papers in this special section were originally presented at the 2008 IEEE Intelligent Vehicles Symposium (IV'08) held in Eindhoven, The Netherlands, on June 4-6, 2008.

Density, speed and flow are the three critical parameters for traffic analysis. Traffic management and control with good performance requires the estimation/prediction of distance mean speed and density for large spatial and temporal coverage. Speed, including time mean speed and distance mean speed, and flow are relatively easy to be measured and...

Microscopic simulation has been widely adopted to predict future traffic conditions. Vehicle-to-vehicle communication of hazard alerts has been proposed for use on freeways, but its impact on freeway traffic has not been evaluated. This paper describes the method of modeling freeway incidents with and without the use of vehicle-to-vehicle (V2V) haz...

In support of efforts to improve traffic signal timing to accommodate bicyclists' needs, observations were made of the timing of bicyclists' intersection crossing maneuvers. Video recordings were made of bicyclists' crossings and the video images were processed to extract the bicyclists' trajectories. These trajectories were synchronized with video...

The recent DARPA-sponsored automated vehicle "Challenges" have generated strong interest in both the research community and the general public, raising consciousness about the possibilities for vehicle automation. Driverless vehicles make good subjects for the visually-oriented media, and they pose enough interesting research challenges to occupy g...