research report

Transportation Management Center (TMC) Performance Measurement System

Publication Date

September 29, 2010

Associated Project

A Measurement-Based System for TMC Performance Evaluation

Author(s)

Will Recker, Craig Rindt

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Intelligent Transportation Systems, Emerging Technologies, & Big Data

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Abstract

This project developed a web-based application that addresses the problem of identifying the value of the TMC in managing disruptions to the transportation system by quantifying the delay savings that can be attributed directly to TMC actions. Using event data from TMC activity logs and traffic state data from the PeMS database, the system identifies the time-space impact of events in the activity database using a mathematical-programming formulation to match evidence of disruption to computed time-space bounds. Given this boundary, the actual delay associated with the impacted region is calculated. To compute the savings attributable to the TMC, the activity logs are used to identify when the direct disruption by the event is removed (e.g., when an accident is cleared) and models the increased delay that would occur if this clearance was delayed. Given these calculations, the system allows TMC managers to evaluate the performance of various bundles of TMC technologies and operational policies by mapping their effects onto events in the system that can be measured using existing surveillance systems and daily activity logs. The system is deployed atop the CTMLabs service-oriented architecture and is available as a application on the CTMLabs website for use by authenticated users.

research report

Online Freeway Corridor Deployment of Anonymous Vehicle Tracking for Real Time Traffic Performance

Publication Date

September 27, 2010

Associated Project

Online Freeway Corridor Deployment of Anonymous Vehicle Tracking for Real-Time Traffic Performance Measurement

Author(s)

Stephen Ritchie, Andre (Yeow Chern) Tok, Shin-Ting (Cindy) Jeng, Hang Liu, Sarah Hernandez, Jin Choi

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Intelligent Transportation Systems, Emerging Technologies, & Big Data

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Abstract

The need for advanced, accurate and comprehensive traffic performance measures in increasingly saturated traffic networks is stretching the effectiveness of existing conventional point-based loop detector traffic data. This study had two objectives. The first was the evaluation of two emerging technologies – Sensys Magnetometers and Blade Inductive Signature System – to assess their potential in providing advanced traffic performance measures using vehicle signature data. The second was the expansion and deployment of the Real-time Traffic Performance Measurement System (RTPMS) to provide section-based traffic performance measures under actual operating conditions. As a part of this deployment, a communications framework was implemented to provide real-time communications of signature feature data between field units and a central vehicle re-identification server. A new improved online interactive web-user interface was also developed to provide users with real-time as well as historical traffic performance measurements.

conference paper

An Empirical Study of Inter-Vehicle Communication Performance Using NS-2

Publication Date

July 31, 2010

Associated Project

Theoretical and Simulation Studies of Information Throughput and Communication Delay of Inter-Vehicle Communication Networks

Author(s)

Jae Young Jung, Rex Chen, Wenlong Jin, R. (Jay) Jayakrishnan, Amelia Regan

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data

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Abstract

In recent years, there has been increasing interest in inter-vehicle communications (IVC) based on wireless networks to collect and distribute traffic information in various Intelligent Transportation Systems applications. In this paper, we study the performance of IVC under various traffic and communication conditions by means of simulation analysis. We consider impacts of shock waves, transportation network, traffic densities, transmission ranges, and multiple information sources. We used a state-of-the-art communication network simulator ns-2 to measure the probability of success (success rate) and message delivery ratio (MDR) for flooding-based IVC communication. For reasonable realism in the deployment scenario, we assume that only a partial set of vehicles on the road are equipped with communication devices, according to the market penetration rate. A Monte-Carlo simulation method is used, with repeated random sampling of IVC-equipped vehicles. The results indicate how these parameters can impact the performance of IVC communications. By comparing the flooding-based approach (theoretical and simulation) and simulation results using AODV (Ad Hoc On-Demand Distance Vector), we conclude the importance of traffic environment and network protocol in determining the MDR for IVC communication.

research report

The Personal Travel Assistant (PTA): Measuring the Dynamics of Human Travel Behavior

Publication Date

July 31, 2010

Associated Project

The Personal Travel Assistant (PTA): Measuring the Dynamics of Human Travel Behavior

Author(s)

Will Recker, James Marca, Craig Rindt, Rina Dechter

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data Travel Behavior, Land Use, & the Built Environment

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Abstract

A simple, continuously collected GPS sequence was investigated to determine whether it can be used to accurately measure human behavior. Hybrid Dynamic Mixed Network (HDMN) modeling techniques were applied to learn behaviors given an extended GPS data stream. A key design decision behind the proposed architecture was to use an Enterprise Service Bus (ESB) to provide a communication infrastructure among various components of the application. Personal Travel Assistants running on mobile devices like cell phones could help travelers change their travel plans when routes are affected by crashes or natural disasters.

working paper

Charge It: The Promise of Plug-in Electric Hybrids

Publication Date

June 30, 2010

Author(s)

Will Recker, Jee Eun (Jamie) Kang

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

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Abstract

This study found that plug-in hybrids can significantly reduce emissions and energy consumption in urban settings where average trip distances are fairly short. The ability of plug-in hybrids to deliver environmental benefits will rely heavily on initiatives that reduce charging times and provide wider opportunities for charging outside the home. in this regard, we recommend enacting policies that 1) encourage affordable conversion from 120-volt to 240-volt charging at home and 2) provide for installation of 240-volt charging facilities at public and private parking facilities adjacent to major activity centers, like shopping malls and rail transit stations.

Phd Dissertation

Mediating change and changes in mediation adapting ICTs for just environmental governance

Publication Date

June 29, 2010

Author(s)

C. Smith

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data Travel Behavior, Land Use, & the Built Environment

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Abstract

Information and communication technologies (ICTs) are important research areas for scientists examining theories of communication, conflict resolution and collaborative decision-making, particularly because they offer impressive analytical capabilities and the capacity to integrate different modes of deliberation and forms of content. The exponential growth in the adoption and diffusion of these digital media currently has, and will likely continue to have, considerable social ecological implications in part because ICTs are increasingly positioned as places of convergence for politically contested information and knowledge. However, the nature of these implications, especially questions concerning how these technologies influence or mediate changes in policy and/or the policymaking process itself is unclear and controversial. Technological enthusiasts, for example, argue that ICTs have potential to upgrade democracy by improving the way we devise means to clarified ends whereas technological pessimists challenge that, far from ushering in a new age of democracy, new media technologies actually hinder coordinative action by reducing more personalized modes of communication. This research examined both face-to-face and online communication facilitated by three institutions in California–the South Coast Air Quality Management District (SCAQMD), the California Environmental Justice Action Committee (CEJAC) and Communities for a Better Environment (CBE)–as they sought to reach decisions concerning a series of environmental justice-related issues. Informed by a mixed methodological approach, this research characterizes the challenges and opportunities afforded by the traditional face-to-face (F2F) settings hosted by the three organizations (i.e., public hearings, public meetings and workshops, respectively) and communication within these settings differed from and integrated with EJ communication in the institutions’ corresponding new media or ICT-based environments (i.e., general content websites and interactive mapping applications). The research found that, while there were obvious limitations to F2F participation, the pragmatic modes of communication that took place in these three settings were not replicated in the online environment. Most troublesome was that ICT-based communication tended to be less trustworthy, interactive and coherent than corresponding communication in F2F settings. The dissertation concludes by putting forth an alternative ICT-based framework for just environmental governance that enables interdependent, multi-directional and adaptive forms of knowledge production and decision-making.

Phd Dissertation

Development of a spatially and temporally resolved planning tool for deployment of hydrogen infrastructure

Publication Date

June 29, 2010

Author(s)

Shane Stephens-Romero

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Zero-Emission Vehicles & Low-Carbon Fuels

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Abstract

While the world relies on the combustion of petroleum based fuels to power more than 90% of its transportation, three principal forcing functions are creating a the need to transition to alternative transportation fuels: (1) The impact of anthropogenic greenhouse gas emissions on the global climate; (2) urban air pollution; and (3) energy security. It is increasingly recognized that meeting future greenhouse gas (GHG) reduction, air quality, and energy security goals will require that the future transportation mix include hydrogen in fuel cell electric vehicles (FCEVs). Transitioning to alternatives like hydrogen will require business and policy leaders to invest in new infrastructure cognizant of future energy and environment goals. An advanced planning methodology can play a vital role in this process by delineating the impacts of fully built-out infrastructure scenarios relative to long-term environment and energy security goals, and facilitating the identification of preferred infrastructure roll-out scenarios, thus targeting investments to where they will be most effective. Until now an integrated planning capability for the deployment of alternative transportation fuels has not been available. This research develops and demonstrates the utility of such a planning tool with a focus on hydrogen as a transportation fuel. The tool is then exercised to show that: *A transition to a fully built-out hydrogen infrastructure scenario leads to significant improvements in urban air quality. Reductions in peak 8-hour average ozone and 24-hour PM2.5 of 10% and 15% respectively are observed. *Greenhouse gas reductions on the order 63% compared to gasoline internal combustion engine of are observed for hydrogen infrastructure scenarios where FCEVs reach a 75% share of passenger vehicles. *Compared to the number of existing gasoline stations, a fraction of the number of hydrogen fueling stations (12 – 15%) can provide a similar level of accessibility for drivers in a specific city used as an example. Community statistics inform the rollout order for hydrogen fueling stations. *Systematic planning optimizes both the economic and environmental impact of hydrogen infrastructure by targeting investments to where they will be most effective in meeting renewable hydrogen standards and providing customer accessibility to hydrogen fueling stations.

Phd Dissertation

Comprehensive Assessment of Managed Lane Performance and Characteristic

Publication Date

May 18, 2010

Author(s)

Chih-Lin (Albert) Chung

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience

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Abstract

Managed lanes, specifically for high occupancy vehicle (HOV) and high occupancy and toll (HOT) lanes, face such undiscovered issues as their performance regarding speed dispersion, equilibrium relationships with general purpose (GP) lanes in terms of speed and level of service, and joint effects of managed lane policies like eligibility, access control, and pricing. The goal of this dissertation is to provide theoretical and practical procedures of managed lane operation assessment under four modules. The first module correlates speed dispersion with the fundamental traffic flow parameters. It reveals that coefficients of variation of speed for HOV and GP lanes are exponential with occupancy, negative exponential with space mean speed, and two-phase linear to flow. The second module proposes two speed equilibrium schemes for HOV and GP lanes. The schemes present distinct speed pairs by congestion level, but speed of HOV lanes is identically ensured no less than GP lanes. The second module also develops an HOT scheme that adopts value of time and value of reliability to formulate HOT tolls with respect to speed of GP lanes. The third module identifies lane management and congestion hot spots by contrasting the level of service of managed lanes and GP lanes in deterministic and stochastic ways. The case study indicates that lane management hot spots are spatially and temporally dynamic, and a non-hot spot less likely turns to congestion without being a lane management hot spot as transition, or vise versa. The last module develops two macroscopic approaches to screening the policy combination set of managed lanes. The optimal/non-inferior policies for non-eliminated combinations are verified by multi-objective binary integer linear programming.

Phd Dissertation

An Adaptive Control Algorithm for Traffic-Actuated Signalized Networks

Publication Date

June 2, 2010

Author(s)

Xing Zheng

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Intelligent Transportation Systems, Emerging Technologies, & Big Data

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Abstract

With advances in computation and sensing, real-time adaptive control has become an increasingly attractive option for improving the operational efficiency at signalized intersections. The great advantage of adaptive signal controllers is that the cycle length, phase splits and even phase sequence can be changed to satisfy current traffic demand patterns to a maximum degree, not confined by preset limits. To some extent, traffic-actuated controllers are themselves “adaptive” in view of their ability to vary control outcomes in response to real-time vehicle registrations at loop detectors, but this adaptability is restricted by a set of predefined, fixed control parameters that are not adaptive to current conditions. To achieve the functionality of truly adaptive controllers, a set of online optimized phasing and timing parameters are needed. This dissertation proposes a real-time, on-line control algorithm that aims to maintain the adaptive functionality of actuated controllers while improving the performance of signalized networks under traffic-actuated control. To facilitate deployment of the control, this algorithm is developed based on the timing protocol of the standard NEMA eight-phase full-actuated dual-ring controller. In formulating the optimal control problem, a flow prediction model is developed to estimate future vehicle arrivals at the target intersection, the traffic condition at the target intersection is described as “over-saturated” throughout the timing process, i.e., in the sense that a multi-server queuing system is continually occupied, and the optimization objective is specified as the minimization of total cumulative vehicle queue as an equivalent to minimizing total intersection control delay. According to the implicit timing features of actuated control, a modified rolling horizon scheme is devised to optimize four basic control parameters–phase sequence, minimum green, unit extension and maximum green–based on the future flow estimations, and these optimized parameters serve as available signal timing data for further optimizations. This dynamically recursive optimization procedure properly reflects the functionality of truly adaptive controllers. Microscopic simulation is used to test and evaluate the proposed control algorithm in a calibrated network consisting of thirty-eight actuated signals. Simulation results indicate that the proposed algorithm has the potential to improve the performance of the signalized network under the condition of different traffic demand levels.

working paper

Commercial Motor Vehicles' Safety - A California Perspective

Publication Date

April 30, 2010

Author(s)

Gen Giuliano

Areas of Expertise

Freight, Logistics, & Supply Chain Safety, Public Health, & Mobility Justice

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Abstract

This report presents the findings of an examination of commercial motor vehicle crashes in California. Initially, a review of the basic descriptive statistics associated with truck-involved crashes in California was conducted; it covered the time period between January 1995 and December 2004 based on the Statewide Incident Tracking and Reporting System (SWITRS) data base, which contains information about every single motor vehicle accident in the state reported to a law enforcement agency. In addition to examinations of the entire population of truck-involved crashes in the state over the designated period, truck-involved crashes in Los Angeles County and the San Francisco Bay Area were also investigated. The next part of the report investigated the rates of truck accidents across California to determine the risk factors involved, including exposure to truck crashes, environmental conditions and demographic factors. The investigation involves modeling crashes as a function of these risk factors based on SWITRS data between 1998 and 2004.