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Quality data collection, processing, and analysis are foundational to good research, policy making and regulation development. With the rapid development of Connected Automated Vehicles (CAV) technologies, it is urgent for both researchers and policy makers to obtain and evaluate good quality CAV data to better understand CAV impacts. CAV hardware-in-the-loop (HIL) tests can expedite CAV performance evaluation and system implementation. This research aims at equipping an existing HIL test tool with data management functions. To this end, a database instance on MySQL has been integrated with an existing HIL test tool. The improved HIL test tool can greatly streamline CAV data collection and quality so that it is beneficial for performance analysis. A detailed comparison and selection of available database tools, database instance design and implementation have been performed to help other California institutes develop and improve their own systems. A user-friendly test tool setup guide and a specific user guide have been provided to enable potential users to easily get started using the data management functions. In addition, two example CAV tests are presented to demonstrate the detailed data collection and performance evaluation procedure. Those examples can serve as a guide to assist users in applying the HIL test tool in their own CAV tests.

Connected Automated Vehicles (CAVs) are similar to other automated vehicles with the distinguishing difference being that CAVs obtain information about road conditionsdirectly from other vehicles and infrastructure (e.g., traffic signals, road sensors) rather than relying solely on onboard sensors. Different CAV technologies are currently being tested and evaluated to assess the prospects for future implementation. These tests involve moving CAV-equipped vehicles on a physical test track and recording how the vehicles operate under different traffic conditions (Figure 1). Since it is difficult and expensive to recreate multiple real-world driving conditions on a single test track, virtual environments are typically used to simulate different traffic conditions, such as traffic signal operation, actions by other vehicles on the road, and other scenarios. These virtual hardware-in-the-loop (HIL) tests can expedite CAV performance evaluation and inform future system implementation; however, existing HIL test systems often lack the ability to manage large amounts of test data, which limits the value and use of these tests.

Connected and automated vehicles hold the potential for substantial improvements to traffic safety, travel time reliability, roadway capacity, and environmental impacts and managed lanes have the potential to be ideal testbeds for CAV technologies. The purpose of this report is to identify specific opportunities to leverage California’s managed lane network as early experimental and pilot deployment sites for CAVs. To this end, we have conducted a detailed inventory of the managed lane facilities in California and applied evaluation criteria to identify two promising sites for future CAV tests and initial deployments. Our study recommends the I-15 Express Lanes in San Diego and the I-10 Express Lanes in Los Angeles for future CAV tests. In this report, we have also documented the major CAV applications that are being considered by USDOT for near-term deployment. After assessing which of the CAV applications are best suited for deployment in managed lanes, we selected the following five applications to be considered for testing in the two California sites: highway CACC, V2I speed harmonization, freeway merge coordination, automated bus rapid transit, and automated barrier mover vehicle. Next, we presented conceptual test and deployment plans for those five CAV applications along with various testing scenarios. We then presented an analysis of the likely timeline for testing and pilot deployment and related vehicle and infrastructure requirements of those applications. For most of the applications, there will be at least two years of preparation required before testing or initial deployment can occur. Finally, our report describes the expected benefits of deploying the selected CAV applications at the proposed sites including increased capacity, reduced congestion and smoother traffic flow in managed lanes and some related improvements to safety.

This report documents the field test of Variable Speed Advisory (VSA) which is an Active Traffic Management strategy.  The test site for the VSA is on State Route 78 Eastbound (SR-78E) from Vista Village Drive (in the City of Vista) to the freeway interchange point of SR-78E and U.S. Route 15 (in the city of Escondido).  This test segment is a three-lane freeway with a posted speed limit of 65 mph and it has 10 on-ramps and 10 off-ramps.  The project was funded by the California Department of Transportation (Caltrans) Division of Research Innovation and System Information (DRISI) under Contract Number 65A0587.  Real-time traffic detector data including flow, speed, and occupancy from pre-existing loop detectors in the field test site, were transmitted via the internet by engineers at Caltrans District 11 (D11) Transportation Management Center (TMC) to a server located in the offices of California Partners for Advanced Transportation Technology (PATH).  This data was then aggregated with real time speed data, captured every 30s [seconds] by radar equipment installed along with solar panel powered LED display equipment, for the display of a VSA, at 7 different sites along a 10.8 mile section of SR 78E.  These two sources of data were then processed for the estimation of the overall traffic state along the corridor, which was in-turn used to calculate the VSA for each section in order to maximize overall traffic throughput through recurrent bottlenecks on SR-78E.  Calculated VSA values were then rounded to multiples of 5 mph and displayed on the VSA signs.  Public outreach was conducted by Caltrans D11 Public Information Office (PIO) to educate the public about the VSA test, and encourage their compliance with posted speed advisories.  A publicly accessible website was also developed for the real-time display of Google Traffic, traffic state, and VSAs displayed in the field.  This site was used extensively by Caltrans management, the project team, and by the public drivers.  After different stages of the system development, integration, and installation process were completed, a progressive test procedure was executed to mitigate any potential negative impacts on traffic operation.  This procedure included dry-runs (saving data for analysis without roadside display), error detection, system tuning, preliminary testing, and extensive tests for data collection for four weeks.  The results of the performance analysis, conducted with an independent PeMS data set, illustrated an improvement in three performance measures for the AM (6-9AM) peak hours: Vehicle Miles Traveled (VMT) increased by 2.72%; Vehicle Hours Traveled (VHT) decreased by 6.28%, and the average speed over the road segment or Q=VMT/VHT increased by 8.71%.  In PM peak hours (2-7PM), two of the three performance measures improved: VMT did not have noticeable improvement; VHT decreased by 1.47% on average;  and Q increased by 2.80% on average.

The objective of this project was to develop recommendations toward a statewide policy of congestion responsive freeway ramp metering (CRRM) operation. The research has been performed in the following approaches: First an empirical “before” and “after” freeway corridor performance evaluation was performed on a selected set of California’s freeway corridors that had implemented congestion responsive ramp metering. Next, other important policy and operational factors that impact the effectiveness of extended hours ramp metering were evaluated: traffic detector health and data quality and their potential impact on CRRM operation, immediate operation hours, ramp metering (RM) light setting to “Green-Ball” or “Black”, on-ramp storage capacity effects and some alternative solutions to reduce/avoid queue-override, and properly handling institutional relevant issues to gain support from local jurisdictions. The corresponding recommendations are included in this report.

Cooperative Adaptive Cruise Control (CACC) provides an intermediate step toward a longer-term vision of trucks operating in closely-coupled automated platoons. There are important distinctions between CACC and automated truck platooning. First, with CACC, only truck speed control will be automated, using vehicle to vehicle (V2V) communication to supplement forward sensors. The drivers will still be responsible for actively steering the vehicle, lane keeping, and monitoring roadway and traffic conditions. Second, while truck platooning systems have relied on a Constant Distance Gap (CDG) control strategy, CACC has relied on a Constant-Time Gap (CTG) control strategy, where the distance between vehicles is proportional to the speed. For these reasons, a series of trucks using CACC is referred to as a string, rather than a platoon. This report mainly focuses on describing the various CACC operational concept alternatives at the level of individual vehicles, local groups of vehicles and their drivers, and which alternatives should be employed in this research project. These operational concepts can be broken into four categories: string formation, steady-state cruising, string split maneuvers, and faults or abnormal operating conditions.

This research identifies the operational concepts for managing cooperative adaptive cruise control (CACC) vehicle maneuvering and traffic flows. This includes approaches for grouping the CACC vehicles, ranging from ad-hoc to centrally coordinated strategies, and the incentives that could be used to facilitate the vehicle clustering, both operational and financial. These are particularly important at low market penetrations, when the CACC vehicles are likely to be widely separated. The dissolution of CACC strings is also discussed, since this needs to be done carefully to avoid adverse traffic impacts. While the main focus is on vehicle-to-vehicle (V2V) CACC for use on limited access highways, strategies for infrastructure to vehicle (I2V) CACC and for both V2V and I2V CACC on signalized arterials are also considered. Connected Cruise Control (CCC), which has been developed as a driver-advisory transitional strategy to lead toward CACC in the Netherlands, is also discussed.

The work reported here includes the development of the underlying theory for detecting traffic flow breakdown at a bottleneck and for defining the speed profiles that vehicles should be following in order to maximize the flow through the bottleneck region. It also includes a preliminary test of the communication of the variable speed limit values to an instrumented vehicle for display to drivers from the general public, in order to determine their reactions to the variable speed limits. The selection of variable speed limits (VSL) to reduce traffic breakdowns is based on careful modeling of the traffic dynamics and estimation of the probability of breakdown as a function of traffic speed and density. The VSL values chosen by the algorithm developed here were broadcast to a test vehicle driven along the I-80 corridor by 16 drivers from the general public, and their reactions to the VSL information were captured by recording data about their driving behavior and collecting their responses to a questionnaire. These results indicated that although the VSL concept is very promising, the implementation needs to provide for better filtering of noisy and inconsistent data so that drivers receive a display of VSL values that are stable in location and time and appear believable to the drivers.

This project has shown how connected vehicle systems, based on vehicle-vehicle and vehicle-infrastructure communication and coordination, can support the development of mobility-enhancing applications with the potential to transform the performance of the road transportation system. Three separate mobility-enhancing applications were developed, simulated, and tested, and their expected mobility benefits were estimated using simulations. Cooperative adaptive cruise control was shown to have a high potential for user acceptance, and when applied at the gap settings chosen by representative drivers from the general public, it could double the capacity of a highway lane at full market penetration. Variable speed limits were shown to have the potential to reduce the adverse impacts of highway bottlenecks by increasing the traffic flow capacity of those bottlenecks if they can be implemented with smooth transitions in the speed limit settings. Automated truck platoon control was shown to be technically feasible using DSRC for vehicle-vehicle coordination, with the potential for significant fuel savings from aerodynamic drag reductions.

This report shows a successful application of 5.9 GHz DSRC with 100 ms update intervals to coordinate the automatic longitudinal control of a platoon of three Class 8 tractor-trailer trucks. The trucks were tested not only in constant-speed cruising conditions, but also through acceleration and deceleration profiles, up and down grades, and in platoon join and split maneuvers using the DSRC coordination. These tests showed acceptable vehicle following accuracy, ride quality and platoon stability. The gaps between the trucks were varied between 10 m and 4 m to evaluate the effects of aerodynamic drag reductions on fuel savings. The most complete set of drag data, at the 6 m gap, showed fuel savings of about 4-5% for the lead truck and in the range of 10% to 14% for the following trucks. The effects of platoon gap variations between 10 m and 4 m were more difficult to determine with certainty because strong ambient winds during those tests led to large differences in the results depending on the truck direction of travel, but the results imply a significant potential for larger savings at the shorter gaps.

This report examines the impact and feasibility of using urban railway system for freight movement. In particular, using the Bay Area Rapid Transit (BART) system for FedEx Express air cargo movement is analyzed as a case study. Based on the framework constructed in the study of last phase, social impact (externalities), reliability, and infrastructure feasibility are considered. The social cost related to emission, energy consumption/efficiency, impact on road traffic and land use is considered. The reliability issue is examined from two aspects: transportation delay, and emergency situation handling. The infrastructure feasibility is analyzed based on the proximity and accessibility of BART yards/shops/stations and FedEx collection/distribution centers, the air freight container size, and the conceptual designs of dedicated BART freight car and transshipment equipment.

This report describes the development of two of the three mobility applications that PATH is developing and evaluating under the sponsorship of the FHWA Exploratory Advanced Research Program, with cost share funding provided by PATH TO 6224. These applications are intended to use DSRC wireless communications among vehicles and between vehicles and the roadway infrastructure to improve mobility on limited-access highways. The first application combines ramp metering with variable speed limits to enhance control of traffic so that traffic flow breakdowns can be deferred or avoided at bottleneck locations. The second application uses vehicle-vehicle communication to improve the performance of adaptive cruise control systems so that they can operate safely with smaller longitudinal gaps and vehicle-roadside communication to provide adjustments to their set speed and gap settings to adapt to changes in local traffic conditions.

This report documents a practical work conducted at California PATH for developing a portable tool to be used at the control cabinet level to accurately diagnose any fault(s) of a loop detection system (including loop circuits, loop cards, cable links, etc.), to check the detection accuracy, to deal with sensitivity of detector card, and to correct the faulty data. To achieve these functionalities at the low level, it is necessary to utilize an independent source as a baseline data to compare against the loop detection system output. Such a comparison also permits an evaluation of the loop system. Since multiple-vehicle tracking technologies using digital video camera on freeways have been well-developed and tested at PATH, it is used as the baseline measurement in the portable tool for the loop fault diagnosis. This report presents the development of a prototype system including the hardware, the software, the data communication method, and the algorithms. Some preliminary consideration has also been conducted on lower (control cabinet) level data correction and communication system reliability of several Caltrans District for sensor data passing. Future work will be on systematic loop fault detection and lower level data correct.

From an operation viewpoint, traffic breakdown (from free-flow) was defined as when the average speed of traffic drops below a certain threshold. It is known that traffic breakdown is a stochastic phenomenon which can happen even when the traffic flow is below the capacity. The capacity has many definitions, such as that in HCM or the average of maximum daily flow. This study investigates the probability of breakdown at certain locations of freeway. The motivation is to find a practical capacity for each freeway section for active traffic control/operation purposes, which could be different from previous viewpoints. Capacity is usually expressed in terms of flow rate. Nevertheless, it is well known that a particular value of flow rate could represent two different traffic states: uncongested and congested. Therefore, simply considering flow rates as the main factor is inadequate for operational purpose. In this study, a bivariate Weibull distribution is adopted to model the probability of breakdown as a function of both mean speed and occupancy of the incoming traffic. The methodology of constructing and calibrating the bivariate distribution is introduced. In addition, three case studies are performed to test the methodology proposed herein. The case studies are carried out by using three different datasets: PORTAL, PeMS, and BHL (Berkeley Highway Lab). PORTAL is an archived data source collected from freeways in Oregon, while the other two are collected from freeways in California PATH. The datasets measure and process flow rates, occupancies, and speeds of traffic from the loop stations on the freeways. Empirical results derived and their potential applications are discussed for developing various traffic control strategies including Variable Speed Limit (VSL) and ramp metering.

This report describes the concept of operations for the three mobility applications that PATH is developing and evaluating under the sponsorship of the FHWA Exploratory Advanced Research Program. These applications are intended to use DSRC wireless communications among vehicles and between vehicles and the roadway infrastructure to improve mobility on limited-access highways. The first application combines ramp metering with variable speed limits to enhance control of traffic so that traffic flow breakdowns can be deferred or avoided at bottleneck locations. The second application uses vehicle-vehicle communication to improve the performance of adaptive cruise control systems so that they can operate safely with smaller longitudinal gaps and vehicle-roadside communication to provide adjustments to their set speed and gap settings to adapt to changes in local traffic conditions. The third application uses vehicle-vehicle communication to enable three tractor-trailer trucks to drive in a coordinated platoon at short enough gaps that they can substantially reduce their aerodynamic drag and increase the effective capacity of their lane.

The San Francisco Bay Area has one of the most congested metropolitan corridors in both California and nationwide, with very high demand for both passenger and air-freight transport. It is also a main entrance to the United States for the huge Asia market, and thus critical for the United States to play a leading role in the global economy. On one hand, traffic congestion in the main corridors through the Bay Area is severe and is becoming worse with the rapid increase of population and the development of the local economy, in which a substantial impact is created by truck-related activities such as the ever increasing air freight business (performed by companies such as Federal Express, UPS, DHL, and CNF). On the other hand, the San Francisco Bay Area Rapid Transit District (BART) operates a regional environmentally-green transit system has excess capacity during non-commute periods and during the commute on some lines in some reverse-commute direction. If the BART system were to be used by the air-freight delivery service providers, BART could probably provide reliable service to integrated air freight carriers to meet their limited-time window delivery service needs. This would lead to additional revenue generation for BART. For the traveling public as well as local, regional, and state government it would reduce truck activity, and its corresponding negative impacts on traffic, environment, safety, land use and the economy. Using BART for air freight movement as a model for combined goods and passenger movement can be generalized to other critical corridors nationwide to effectively relieve corridor congestion problem. Improving movement through these critical metropolitan corridors could yield significant benefits in terms of reduced travel time and delays and increased reliability and predictability of both passenger and freight movement.

This final report describes the process and product from the project, Onboard Monitoring and Reporting for Commercial Motor Vehicle Safety (OBMS), in which a prototypical suite of hardware on a Freightliner Century Class truck was developed and tested.The OBMS suite allows for online measurement of a set of driving characteristics which are indicators of unsafe driving behavior. These characteristics include speed, following distance, lane keeping performance, safety belt use, and the use of turn signals. Feedback can be provided to the driver, either directly via real time feedback or through carrier management, to allow drivers to significantly improve their safety performance. For example, if a driver receives a report that he/she is not using his/her turn signals during lane changes, that driver can then be monitored during a follow up period to determine if feedback had corrected the deficiency. This concept would be pioneered in commercial fleets because they have the resources and organizational structure to provide feedback and training to professional drivers. This concept differs from commercial onboard devices in that it is an ensemble set of instruments – not one or a few warning devices – with a safety focus and different feedback modalities. It is comprehensive in that it addresses crash causes and provides ‘corrective’ feedback in real time and/or post-trip feedback, depending on the particular subsystem(s) which are activated. In essence, the objective is to improve and maintain driver safety behaviors. Thus, it does not explicitly address fleet management or other non-safety operations, for example vehicle location and tracking or fuel economy.A systems engineering process was applied to this research, resulting in a prototypical OBMS hardware suite and a plan to follow up this effort with a FOT. This project is the result of a Federal Motor Carrier Safety Administration Cooperative Agreement with Caltrans, it was undertaken by the California Partners for Advanced Transit and Highways (PATH) program, with assistance from the California Center for Innovative Transportation (CCIT) and a subcontractor, Advanced Systems Engineering Consulting.

A big segment of the traffic signal control systems in California and United States are closed-loop systems. Because wide-scale deployment of advanced adaptive control systems may be many years away due to the associated high costs, there is a significant need to improve the effectiveness of the state-of-the-practice closed-loop systems. To address the need, this project focuses on: 1) developing an integrated micro-simulation/signal optimization tool to enhance the capability of generating efficient signal timing plans, and 2) developing a systematic approach to make closed-loop systems be more robust and traffic responsive.An integrated simulation/signal optimization tool can generate, evaluate and fine tune signal timing plans in a cohesive manner. This report presents an approach for integrating Paramics with Synchro and TRANSYT-7F. Two sets of Paramics plug-ins are developed to facilitate the two-way data conversion between Paramics and Synchro or TRANSYT-7F. The first set of plug-ins read Paramics network data and traffic volume data and generate Synchro or TRANSYT-7F data files while the second transfer optimized signal timing data back to Paramics. These tools may assist traffic engineers in developing efficient signal timing plans for arterial traffic operations. Step-by-step tutorials are also included in the report to teach how to use the new plug-ins.The advancement and deployment of telecommunication and ITS technologies make traffic and signal status data more readily available. These high-resolution data provide opportunities to allow closed-loop control systems to operate more adaptively and robustly to the changes in traffic demands and patterns. This report presents a systematic approach to make use of traffic and signal data to further improve the control performance of closed-loop systems. The systematic approach includes three components: timing, monitoring, and fine-tuning. For timing, two innovative models are developed to generate robust optimal signal timings that are less sensitive to fluctuations of traffic flows at the same time minimizing the mean of the delays per vehicle across all possible realizations of uncertain traffic flows. Another procedure is proposed to optimally determine time-of-day intervals for time-of-day controls based on a large set of archived traffic data. For monitoring, a prototype signal performance monitoring system is developed to report performance measures of signal control operations and help traffic operation staffs make the decision whether a retiming or fine-tuning effort is needed or not. Finally, for fine-tuning, an offset refiner is introduced to fine tune signal offsets to provide smoother progression in either one-way or two-way coordination. The offset refiner is easy to implement, and could be run periodically or together with the performance monitoring system. If the signal performance degrades, the refiner can be called to fine-tune the offsets for better progression.

This report is divided into two parts:•Part I - Highway Traffic Data Sensitivity Analysis in Systems Approach. This work has been conducted by Dr. Xiao-Yun Lu at California PATH, U. C. Berkeley.•Part II - Empirical and Analytical Results for Sensitivity to Loop Station Spacing. This work has been conducted by Benjamin Coifman in Civil Engineering, Ohio State University.Since the aspects of the problem considered and approaches adopted by the two are different, it is thus necessary to separate the report into two parts. Each part is self-content.

This report has been prepared as part of a research project developing a combined quantitative and qualitative approach to planning for improved intermodal connectivity at California airports. The quantitative approach involves the development of an Intermodal Airport Ground Access Planning Tool (IAPT) that combines an air passenger mode choice model, a model of transportation provider behavior and a traffic network analysis model. The qualitative approach will be used to enhance the quantitative analysis to account for those factors which are difficult to quantify and to provide recommended policy and planning guidelines. This report represents a continuation of the previously submitted Working Paper, so that together they describe the main work conducted in the first year of the project. This report summarizes the work reported in the Working Paper in Chapter 3: Opportunities for Improved Intermodal Connectivity at California Airports. This report concentrates on the modeling and IAPT design. The modeling includes two main components of the IAPT, i.e. air passenger mode choice model and transportation provider behavior model. This modeling work involves the following steps: •System isolation (definition of problem scope): to isolate the airport ground access system from general transit systems; •System simplification: several assumptions have been developed which greatly simplify the problem to avoid network optimization in a transit system; • Mathematical model development and justification. The IAPT design includes detailed software structure and functions, user interface, data base, and data flow. Plans for further development of the IAPT and recommendations for future study of airport ground access planning issues are presented.

This project studies the coordination layer control and decision making for automated trucks and buses. Maneuver design and coordination algorithms need to take several factors into consideration. Practical achievement in this project includes the following: automated ground vehicle maneuver coordination; maneuver design for automated trucks/buses; model-based simulation package development for control design and real-time code development.