Center for Sustainable Mobility
The Center for Sustainable Mobility (CSM) at the Virginia Tech Transportation Institute (VTTI) is a multi-discipline center that conducts research to develop and evaluate alternative sustainable transportation systems. The center inlcudes the Sustainable Mobility Learning laboratory, a mobile traffic laboratory, a traffic laboratory, and a traffic signal control center. The center includes four groups: (a) Transportation Systems and Operations Group; (b) Traffic Signal Operations Group; (c) Energy and Environmental Group; and (d) Data Visualization Group.
Current Research Projects
Access Control Design on Highway Interchanges
Project Description: There are a number of publications that provide guidance at the national level with regard to the distance from the interchange ramps in which access should be controlled on the crossroad. These publications include suggested spacing between the interchange ramp and the first right-in/right-out access, the first unsignalized full access, and the first signalized intersection. The research investigates the operational impacts of varying access lengths based on field observations, data collection and analysis, and microscopic simulation. Crash experience at existing interchanges with varying access control lengths will be evaluated to help define the influence area and possibly be used to develop safety analysis procedures to predict crashes for varying configurations. The research will synthesize the state of the practice in other states. Older driver reaction and decision making times, vehicle acceleration and deceleration, signing and markings, and potential pedestrian conflicts will also be considered in the investigation of the optimal limited access length as measured from the ramp terminals.
Project Sponsors: Virginia Department of Transportation.
Intersection Collision Warning Field Study
Project Description: In a recently completed study in the FHWA Highway Driving Simulator, it was found that about 70 percent of drivers stopped for an unanticipated warning that was intended to cause them to slow or stop to avoid collision with a hypothetical red-light violator. Ten to 20 percent more drivers responded as desired when the warning was distinctly different from a normal traffic signal phase change. Therefore, it was recommended that a field validation study be conducted using a warning similar to the most effective warning condition in the simulation. Because drivers in the simulator braked harder (decelerated faster) than is usually observed in field studies, verification was needed that drivers in actual vehicles will respond to violator warnings in a manner that will avoid collisions. The objective of the study is to partially replicate the simulator study to verify that drivers will respond to red-light violator warnings with sufficient speed and intensity to avoid a collision with the violator. The tasks of the study include: 1) conduct a field study on the Smart Road test facility using a total of 60 test subjects; 2) characterize driver behavior at the onset of a yellow phase; 3) characterize break reaction times at signalized intersection approachses; 4) characterize driver deceleration behavior at signalized intersection approaches; and 5) develop models to replicate driver stop/go behavior at the onset of a yellow phase.
Project Sponsors: Federal Highway Administration.
Addressing I-81 Transportation Issues
Project Description: Virginia’s mountainous terrain and the large number of trucks that travel on the state’s major highways have resulted in reductions in roadway capacities and levels of service. Researchers at Virginia Tech are studying this problem and its effects on traffic stream behavior. This research effort is important because current procedures for modeling trucks in the 2000 Highway Capacity Manual only consider a single truck of weight-to-horsepower ratio 200 lb/hp. The research effort develops vehicle dynamics models for modeling truck acceleration behavior, models the interaction of trucks and automobiles, enhances the HCM truck performance curves, evaluates the safety hazard of I-81, and evaluates alternative lane and truck management strategies.
Project Sponsors: Virginia Department of Transportation (VDOT) and the Mid-Atlantic University Transportation Center (MAUTC).
Traffic Modeling Issues
Project Description: The objective of this research effort is to use GPS detection technology, together with fully-equipped vehicles, to characterize vehicle behavior in order to provide data that would allow for the enhancement of current state-of-the-art microscopic simulation tools. To achieve this objective, data are being collected along the Smart Road and along typical urban arterial and freeway sections. The data being collected include vehicle speed, acceleration, throttle level, braking indicator, fuel consumed, and emissions every second.
Project Sponsors: Virginia Department of Transportation (VDOT) and the Mid-Atlantic University Transportation Center (MAUTC).
Addressing Urban Network Transportation Issues
Project Description: The majority of transportation problems occur within urban environments. In order to manage and enhance the flow of urban traffic, transportation professionals need tools to evaluate, predict, and control the ever-growing number of vehicles on the roads. Various methods for controlling traffic are emerging, including transit signal priority, in which the timing of the traffic signal is modified to accommodate transit vehicles; adaptive signal control, in which the timing of the traffic signal adjusts according to traffic information monitored through roadway sensors; ramp metering; and toll roads. The project involves 1) developing procedures to estimate the delay upstream of bottlenecks; 2) develop analytical models to estimate the number of stops at over-saturated signalized intersection approaches; 3) develop procedures to calibrate traffic dispersion models; 4) develop procedures to model traffic dispersion microscopically; 5) develop mesoscopic models to estimate traffic stream energy consumption and emissions; and 6) develop analytical procedures to calibrate commercially available microscopic traffic simulation software.
Project Sponsors: Virginia Department of Transportation (VDOT) and the Mid-Atlantic University Transportation Center (MAUTC).
Developing a Fully Instrumented Test Facility
Project Description: The goal of this project is to develop a comprehensive instrumented test bed in the town of Blacksburg to achieve the following objectives: 1) Serve as a real-life test facility for the evaluation and enhancement of traffic flow theory; 2) Develop a database of field data for conducting research on alternative means of disseminating real-time traveler information to the public; 3) Serve as a real-life test facility for enhancing and developing tools for the evaluation of network-wide energy and environmental impacts of operational-level transportation projects; 4) Serve as a real-life test facility for enhancing and developing tools for quantifying the noise impacts of operational-level transportation projects; 5) Serve as a test facility for evaluating emerging ITS technologies that can benefit transit operations; 6) Serve as a test bed for evaluating emerging surveillance and communication technologies; and 7) Serve as a unique educational tool that will allow practitioners, undergraduate students, and graduate students to access and analyze real-life traffic data.
Project Sponsors: National Science Foundation, the Virginia Department of Transportation (VDOT) and the Mid-Atlantic University Transportation Center (MAUTC).
Completed Research Projects
Inclement Weather Impacts on Traffic Stream Behavior
Project Description: It is common knowledge that inclement weather affects traffic stream parameters and behavior. However, it is not clear how these various forms of inclement weather impact traffic stream parameters. Consequently, this research effort combines weather and traffic data to quantify the impact of inclement weather on traffic stream parameters considering three geographic locations in the USA, namely, Baltimore, Minneapolis, and Seattle. The study will develop analytical models to account for inclement weather impacts on roadway capacity and free-flow speed. These factors will be similar to the Highway Capacity Manual (HCM) procedure heavy vehicle, lane width, and lane-changing intensity adjustment factors.
Project Sponsors: Federal Highway Administration (FHWA), the Virginia Department of Transportation (VDOT), and the Mid-Atlantic University Transportation Center (MAUTC).
Analytical Procedures for Estimating Capacity of Feeway Weaving Sections
Project Description: The freeway weaving analysis procedures in the 2000 Highway Capacity Manual (HCM) are based on research conducted in the early 1970s through the early 1980s. Subsequent researches have shown that the methods’ ability to predict the operation of a weaving section is limited. Consequently, this research effort utilizes the INTEGRATION software to estimate the capacity of weaving sections. Subsequently, analytical procedures are developed using the simulated data to estimate the capacity of high intensity lane-changing sections including weaving, merge, and diverge sections.
Project Sponsors: Virginia Department of Transportation (VDOT) and the Mid-Atlantic University Transportation Center (MAUTC).
Dynamic Roadway Travel Time Algorithm Development
Project Description: The project develops algorithms that estimate dynamic roadway travel times. The tasks of the project include: 1) develop algorithms for matching license plate readings; 2) develop procedures to estimate trip travel time variability from segment travel time measurements; 3) characterize daily traffic demand variability; and 4) develop procedures to estimate space-mean-speed from loop detector time-mean-speed measurements.
Project Sponsors: ITS Implementation Center.
Integrating Transit Signal Priority and Adaptive Traffic Signal Control
Project Description: The project investigates the merits of integrating transit signal priority (TSP) within an adaptive traffic signal control system along the Columbia Pike corridor. The tasks of the project include 1) install GPS units on five buses and sample automobiles traveling along the corridor to record second-by-second speed data; 2) develop emission models for transit vehicles; 3) estimate different MOEs from the data; and 4) conduct a statistical analysis of the aggregate data to quantify the impacts on TSP on the various MOEs.
Project Sponsors: Arlington County and the ITS Implementation Center.
Enhancing High Emitter Vehicle Screening Procedures
Project Description: This project aims at refining the practice of screening high emitting vehicles, by supporting the Virginia Department of Environmental Quality on three tasks: 1) converting emission concentration measurements to emission rates; 2) devising techniques to account for the lag between speed/acceleration measurements and tailpipe emission measurements, and 3) devising techniques for screening high emitting vehicles.
Project Sponsors: Virginia Department for Environmental Quality (VDEQ) and the ITS Implementation Center.
Addressing VDOT Surveillance Needs
Project Description: This project was a collaborative effort between Virginia Tech and the University of Virginia. The objective of the study was to develop alogrithms to locate surveillance technology and estimate dynamic roadway travel times. The project tasks included: 1) estimate dynamic roadway travel times using Automative Vehicle Identification (AVI) data; 2) develop algorithms to optimally locate AVI surveillance instrumentation using the Reformulation Linearization Procedure (RLT); and 3) develop a Genetic Algorithm to optimally locate surveillance instrumentation.
Project Sponsors: Virginia Department Department of Transportation and the ITS Implementation Center.
I-77/I-81 Interchange Modeling Study
Project Description: This study involved the modeling of alternative I-77/I-81 overlap designs using microscopic traffic simulation. The tasks of the project included: 1) compare CORSIM and INTEGRATION for the modeling of bottlenecks and 2) develop calibration procedures for the CORSIM software.
Project Sponsors: Virginia Department Department of Transportation and the ITS Implementation Center.
Fuel Doctor Evaluation
Project Description: The Fuel Doctor technology relates to a device and process provided for treatment of a hydrocarbon or fossil fuel which is to be combusted in a combustion chamber to improve combustion of the fuel in the combustion chamber by turbulently treating the fuel with a plurality of fields of magnetic flux and subjecting the fuel to a field of differing standard electrochemical reduction potentials. The device is adapted to be connected in-line in a fuel supply line of the combustion chamber. The objective of the study was to evaluate the impact of the Fuel Doctor technology on vehicle fuel consumption and emissions.
Project Sponsors: Performance Fuel Systems.
Metropolitan Model Deployment Initiative Evaluation
Project Description: This project was intended to provide a comprehensive evaluation of the impact of the Metropolitan Model Deployment Initiatives (MMDI) in Seattle, Phoenix, and San Antonio . As part of his involvement in the MMDI evaluation, Dr. Rakha headed a team that quantified the impact of traffic signal coordination and variable message signs on the system throughput, energy and emissions, and safety. In doing so the team modeled a portion of Phoenix and some portions of San Antonio . Dr. Rakha was also involved in enhancing current energy and emission models together with current safety models. Furthermore, Dr. Rakha was actively involved in research in the area of driver behavior in terms of time of departure, mode of travel, and route of travel.
Project Sponsors: Federal Highway Administration.
Intelligent Infrastructure Deployment Analysis System (IDAS)
Project Description: The objective of the project was to develop a sketch planning tool that assists Metropolitan Planning Organizations (MPO's) and Departments of Transportation (DOT's) in assessing the benefits and costs of Intelligent Transportation System (ITS) and non-ITS options. Partners involved in the project included Oak Ridge National Lab, Cambridge Systematics, and the Center for Transportation Research at Virginia Tech. As part of his work with IDAS, Dr. Rakha was part of a team that developed macroscopic emission and safety models.
Project Sponsors: Federal Highway Administration.
Adaptive Curise Control Evaluation
Project Description: This project involved evaluating the safety and throughput benefits of Adaptive Cruise Control (ACC) systems using field data that were gathered by the University of Michigan. As part of his involvement, Dr. Rakha compared the workload involved in the usage of conventional cruise control to ACC. Dr. Rakha was part of a team that developed a framework for the evaluation of the safety impacts of ACC.
Project Sponsors: Federal Highway Administration.
SWIFT Architecture Evaluation
Project Description: The project entailed an evaluation of the SWIFT (Seattle Wide-Area Information For Travel ers) system architecture. The SWIFT system disseminated real-time traffic information via an FM sub-carrier. Three reception devices received the information, namely: Delco navigation units, PC laptops, and Seiko MessageWatch™ wrist watches. SAIC was responsible for evaluating the SWIFT system and Dr. Rakha was the Co-PI in the system architecture evaluation. This evaluation study involved a number of field tests, questionnaires, and a review of the system architecture.
Project Sponsors: Federal Highway Administration.
Genesis Modeling Study Evaluation
Project Description: Dr. Rakha conducted the Genesis modeling study in the twin cities Minneapolis/St. Paul. The Genesis study involved evaluating the traffic and environmental impacts of Personal Communication Devices (PCD's) including pager systems on the overall performance of traffic. The Genesis system was evaluated using a combination of operational field and modeling tests. Field experiments and surveys collected data and information on the Genesis test drivers. A total of 403 test vehicles were allowed to traverse the Minneapolis/St. Paul network for an entire year. The desire to examine other unobservable factors resulted in the inclusion of a modeling activity using the INTEGRATION model. The INTEGRATION model was initially calibrated to the existing conditions, and then utilized to extrapolate results for conditions that were not encountered during the field test.
Project Sponsors: Federal Highway Administration.
TravTek Modeling and Safety Study
Project Description: Dr. Rakha was involved in evaluating the traffic and environmental impacts of the TravTek route guidance system in Orlando , Florida using the INTEGRATION simulation model. The TravTek evaluation study is the largest field evaluation of a Dynamic Route Guidance System (DRGS) in North America . As part of the TravTek evaluation study, Dr. Rakha analyzed the I-4 ( Orlando , Florida ) Freeway Traffic Management System (FTMS) data, assisted in evaluating the safety of the TravTek route guidance system, and conducted the modeling study of the TravTek system using the INTEGRATION simulation model.
Project Sponsors: Federal Highway Administration.
Research Faculty
Most of the research I have conducted has been in collaboration with other research faculty or with students. The students are listed separately in the students section. Consequently, I am listing the research faculty that I have worked with over the years in alphabetic order.
- Montasir Abbas
- Slimane Adjerid
- Kyoungho Ahn
- Mazen Arafeh
- Mark Baker
- Sergio Demarchi
- Francois Dion
- Ihab El-Shawarby
- Bruce Hellinga
- Antoine Hobeika
- Pushkin Kachroo
- Alejandra Medina
- Kaan Ozbay
- William Perez
- Hanif Sherali
- Mohamadreza Farzaneh
- Raghu Pasumathy
- Laurence Rilett
- Jose Setti
- Brian Smith
- Kiseok Sung
- Antonio Trani
- Michel Van Aerde
- Lei Yu
Last Updated: July 11, 2009