Chen-Fu Liao

Simulation Study of Bus Signal Priority Strategy: Taking Advantage of Global Positioning System, Automated Vehicle Location System, and Wireless Communications

Providing signal priority for buses has been proposed as an inexpensive way to improve transit efficiency and productivity and to reduce operation costs. Bus signal priority has been implemented in several U.S. cities to improve schedule adherence, reduce transit operation costs, and improve customer ride quality. Current signal priority strategies primarily utilize sensors to detect buses at a fixed or preset distance away from an intersection. Traditional presence detection systems, ideally designed for emergency vehicles, usually send a signal priority request after a preprogrammed time offset as soon as transit vehicles are detected without the consideration of bus readiness. The objective of this study is to take advantage of the already equipped Global Positioning System and automated vehicle location system on the buses in Minneapolis, Minnesota, and to develop an adaptive signal priority strategy that could consider bus schedule adherence, number of passengers, location, and speed. Buses can communicate with intersection signal controllers by using wireless technology to request signal priority. Communication with the roadside unit (e.g., traffic controller) for signal priority may be established by using the readily available wireless local area network (WLAN) 802.11x or the dedicated short-range communication (DSRC) 802.11p protocol currently under development for wireless access to and from the vehicular environment. This paper describes the proposed priority logic and its evaluation with the use of microscopic traffic simulation. Simulation results indicate that a 12% to 15% reduction in bus travel time during a.m. peak hours (7 to 9 a.m.) and a 4% to 11% reduction in p.m. peak hours (4 to 6 p.m.) could be achieved by providing signal priority for buses. Average bus delay time was reduced in the range of 16% to 20% and 5% to 14% during a.m. and p.m. peak periods, respectively.

Generalized impedance control of a redundant manipulator for handling tasks with position uncertainty while avoiding obstacles

Positioning uncertainty becomes a major problem for position-control-based robots when operating in contact with the environment. Inaccuracy in positioning parts or inadequate information about part placement has traditionally been addressed through accurate fixturing, calibration and robot programming. Impedance control provides a mechanism for using the reaction forces and torques at the end effector to compensate for positioning uncertainty. Redundant manipulators have greater manipulability than nonredundant manipulators thus facilitating the implementation of more complex tasks, and making it possible to also avoid collisions by taking advantage of the redundancies. Handling positioning uncertainty while simultaneously avoiding collisions are solved by using the generalized impedance control algorithm developed in this study. This was successfully demonstrated on the 7 degree-of-freedom redundant Robotics Research Corporation K1207i manipulator.

Development of internet-based traffic simulation framework for transportation education and training

Many traffic simulation software packages are available to help traffic engineers and researchers study and evaluate the potential impact of proposed traffic management strategies and policies. However, the existing tools require a significant investment in time to learn how to create models, perform calibrations, and, finally, analyze the results. This substantial learning curve severely restricts their application and makes it difficult for engineering students, the general public, and policy makers to take advantage of these tools. An Internet-based traffic simulation framework was developed to enhance the learning experience for transportation students and engineers. Pregenerated traffic scenarios were first implemented as part of an undergraduate civil engineering class. An interactive simulation tool was developed to allow users to make changes to the model and examine the impacts on traffic. This now allows students, for example, to minimize the queue length at the traffic signal by changing the cycle length or splits. This interactive traffic simulation tool was deployed and tested in an undergraduate class of 73 students. Feedback was collected from the instructors and the students and will lead to additional enhancements of the laboratory module. This web-based traffic simulation framework can also incorporate larger road networks that allow one to consider a multiplicity of traffic management strategies, thus providing a valuable tool for educating and training transportation professionals.

Development of Data-Processing Framework for Transit Performance Analysis

A methodological data-processing framework is developed to process a massive amount of transit data, including vehicle location, passenger count, and electronic fare transactions. The developed data analysis methodology can allow a number of applications, such as transit route performance measurement, to support decision making for transit planning and operation. The data analysis methodology is demonstrated by the use of 1 month of archived transit data obtained from Metro Transit in the Twin Cities of Minnesota. A route-based transit performance analysis at time point level is discussed to evaluate route running time and schedule adherence. An application interface was developed to analyze bus adherence at time points and link travel time performance. The data-processing framework has the capability to support studies on transfer activities and transit riders origin and destination inference. The developed data analysis methodology has demonstrated its capability to analyze transit performance and to support further research on other intelligent transit applications.

Generating Reliable Freight Performance Measures with Truck GPS Data

Building on previous efforts to study freight mobility and reliability, a truck GPS data analysis methodology was developed to study the freight performance of heavy commercial vehicles along key freight corridors in the Twin Cities metropolitan area in Minnesota. Twelve months of truck GPS data collected in 2012 were obtained from the American Transportation Research Institute. Several performance measures, such as truck mobility, delay, and reliability measures, were derived and statistically analyzed by route, roadway segment, and time of day. The derived performance measures were validated with available benchmark data to ensure data quality. Data quality validation is important particularly in urban areas where satellite reception may be limited and traffic congestion is more common. For data quality verification, average truck speed and hourly volume percentage computed from the truck GPS data were validated with data from weigh-in-motion sensors, loop detectors, and automatic traffic recorders at selected locations. The analysis methodology using truck GPS data offers potential opportunities for freight planners and managers to generate reliable measures in a timely manner. Findings from this research indicate that those measures derived from the truck GPS data can be used in supporting the U.S. Department of Transportation performance measure initiative and truck and freight modeling in metropolitan areas. The performance measures can provide truck-specific information to support regional surface freight planners in identifying freight bottlenecks and infrastructure improvement needs and in developing operational strategies to promote efficient freight movement for the industry.

Simulating Transportation for Realistic Engineering Education and Training: Engaging Undergraduate Students in Transportation Studies

The practice of transportation engineering and planning has evolved substantially over the past several decades. A new paradigm for transportation engineering education is required to engage students better. Simulation tools have been used by transportation professionals to evaluate and analyze the potential impact of design or control strategy changes. Simulation, which can effectively convey complex transportation concepts, is particularly valuable in transportation education. The use of simulation in transportation education gives students the opportunity to apply different control strategies in a risk-free environment and teaches them transportation engineering methodologies. Despite its advantages, simulation has not been widely adopted in transportation engineering education. Its use in undergraduate transportation courses is sporadic; the reported efforts have been primarily in upper-level technical elective courses. A suite of web-based simulation modules has been developed and incorporated into undergraduate transportation courses at the University of Minnesota. The Simulating Transportation for Realistic Engineering Education and Training (STREET) research project was recently awarded a grant by the National Science Foundation to develop web-based simulation modules, to improve instruction in transportation engineering courses, and to evaluate their effectiveness. The ultimate goal of the STREET project is to become the epicenter for the development of simulation-based teaching materials that provide undergraduates with an interactive learning environment. Given the hands-on aspect of simulation, the hope is that its use will improve student understanding of critical concepts in transportation engineering, and will also enhance student interest in transportation engineering and thereby increase their presence in the field. The intention is to disseminate the results and teaching materials to other colleges so they can integrate these online modules into their curricula.The practice of transportation engineering and planning has evolved substantially over the past several decades. A new paradigm for transportation engineering education is required to better engage students and deliver knowledge. Simulation tools have been used by transportation professionals to evaluate and analyze the potential impact of design or control strategy changes. Conveying complex transportation concepts can be effectively achieved by exploring them through simulation. Simulation is particularly valuable in transportation education because most transportation policies and strategies in the real world take years to implement with a prohibitively high cost. Transportation simulation allows learners to apply different control strategies in a risk-free environment and to expose themselves to transportation engineering methodologies that are currently in practice. Despite the advantages, simulation, however, has not been widely adopted in the education of transportation engineering. Using simulation in undergraduate transportation courses is sporadic and reported efforts have been focused on the upper-level technical elective courses. A suite of web-based simulation modules was developed and incorporated in the undergraduate transportation courses at University of Minnesota. The STREET (Simulating Transportation for Realistic Engineering Education and Training) research project was recently awarded by NSF (National Science Foundation) to develop web-based simulation modules to improve instruction in transportation engineering courses and evaluate their effectiveness. Our ultimate goal is to become the epicenter for developing simulation-based teaching materials, an active textbook, which offers an interactive learning environment to undergraduate students. With the hand-on nature of simulation, we hope to improve student understanding of critical concepts in transportation engineering and student motivation toward transportation engineering, and improve student retention in the field. We also would like to disseminate the results and teaching materials to other colleges to integrate the simulation modules in their curricula.

ROAD: An Interactive Geometric Design Tool for Transportation Education and Training

Traditionally, students use pencil and ruler to lay out lines and curves over contour maps for roadway geometry design. Numerous calculations of stopping sight distance, minimum turning radius, and curve alignments are required during the roadway design process in order to ensure safety, to minimize economic and environmental impacts, as well as to reduce construction costs. Iterative computations during the design process are usually performed manually by the students in order to meet any given design criteria and environmental constraints. The traditional design process of roadway geometry design is often cumbersome and time consuming. It limits students from taking a broader perspective on the overall roadway design process. An Internet-based roadway design tool (ROAD: Roadway Online Application for Design) was developed to enhance the learning experience for transportation engineering students. This tool allows students to efficiently design and to easily modify the roadway design with given economic and environmental parameters. A 3D roadway geometry model can be generated by the software at final design to allow students immerse themselves in the drivers seat and drive through the designed roadway at maximum design speed. This roadway geometry design tool was deployed and tested in a civil engineering undergraduate class in spring 2006 at University of Minnesota, Department of Civil Engineering. Feedback was collected from instructors and students that will lead to additional enhancements of the roadway design software.

Simulating Transportation for Realistic Engineering Education and Training

The practice of transportation engineering and planning has evolved substantially over the past several decades. A new paradigm for transportation engineering education is required to engage students better. Simulation tools have been used by transportation professionals to evaluate and analyze the potential impact of design or control strategy changes. Simulation, which can effectively convey complex transportation concepts, is particularly valuable in transportation education. The use of simulation in transportation education gives students the opportunity to apply different control strategies in a risk-free environment and teaches them transportation engineering methodologies. Despite its advantages, simulation has not been widely adopted in transportation engineering education. Its use in undergraduate transportation courses is sporadic; the reported efforts have been primarily in upper-level technical elective courses. A suite of web-based simulation modules has been developed and incorporated into undergraduate transportation courses at the University of Minnesota. The Simulating Transportation for Realistic Engineering Education and Training (STREET) research project was recently awarded a grant by the National Science Foundation to develop web-based simulation modules, to improve instruction in transportation engineering courses, and to evaluate their effectiveness. The ultimate goal of the STREET project is to become the epicenter for the development of simulation-based teaching materials that provide undergraduates with an interactive learning environment. Given the hands-on aspect of simulation, the hope is that its use will improve student understanding of critical concepts in transportation engineering, and will also enhance student interest in transportation engineering and thereby increase their presence in the field. The intention is to disseminate the results and teaching materials to other colleges so they can integrate these online modules into their curricula.The practice of transportation engineering and planning has evolved substantially over the past several decades. A new paradigm for transportation engineering education is required to better engage students and deliver knowledge. Simulation tools have been used by transportation professionals to evaluate and analyze the potential impact of design or control strategy changes. Conveying complex transportation concepts can be effectively achieved by exploring them through simulation. Simulation is particularly valuable in transportation education because most transportation policies and strategies in the real world take years to implement with a prohibitively high cost. Transportation simulation allows learners to apply different control strategies in a risk-free environment and to expose themselves to transportation engineering methodologies that are currently in practice. Despite the advantages, simulation, however, has not been widely adopted in the education of transportation engineering. Using simulation in undergraduate transportation courses is sporadic and reported efforts have been focused on the upper-level technical elective courses. A suite of web-based simulation modules was developed and incorporated in the undergraduate transportation courses at University of Minnesota. The STREET (Simulating Transportation for Realistic Engineering Education and Training) research project was recently awarded by NSF (National Science Foundation) to develop web-based simulation modules to improve instruction in transportation engineering courses and evaluate their effectiveness. Our ultimate goal is to become the epicenter for developing simulation-based teaching materials, an active textbook, which offers an interactive learning environment to undergraduate students. With the hand-on nature of simulation, we hope to improve student understanding of critical concepts in transportation engineering and student motivation toward transportation engineering, and improve student retention in the field. We also would like to disseminate the results and teaching materials to other colleges to integrate the simulation modules in their curricula.

Engaging Undergraduate Students in Transportation Studies through Simulating Transportation for Realistic Engineering Education and Training (STREET).

The practice of transportation engineering and planning has evolved substantially over the past several decades. A new paradigm for transportation engineering education is required to engage students better. Simulation tools have been used by transportation professionals to evaluate and analyze the potential impact of design or control strategy changes. Simulation, which can effectively convey complex transportation concepts, is particularly valuable in transportation education. The use of simulation in transportation education gives students the opportunity to apply different control strategies in a risk-free environment and teaches them transportation engineering methodologies. Despite its advantages, simulation has not been widely adopted in transportation engineering education. Its use in undergraduate transportation courses is sporadic; the reported efforts have been primarily in upper-level technical elective courses. A suite of web-based simulation modules has been developed and incorporated into undergraduate transportation courses at the University of Minnesota. The Simulating Transportation for Realistic Engineering Education and Training (STREET) research project was recently awarded a grant by the National Science Foundation to develop web-based simulation modules, to improve instruction in transportation engineering courses, and to evaluate their effectiveness. The ultimate goal of the STREET project is to become the epicenter for the development of simulation-based teaching materials that provide undergraduates with an interactive learning environment. Given the hands-on aspect of simulation, the hope is that its use will improve student understanding of critical concepts in transportation engineering, and will also enhance student interest in transportation engineering and thereby increase their presence in the field. The intention is to disseminate the results and teaching materials to other colleges so they can integrate these online modules into their curricula.The practice of transportation engineering and planning has evolved substantially over the past several decades. A new paradigm for transportation engineering education is required to better engage students and deliver knowledge. Simulation tools have been used by transportation professionals to evaluate and analyze the potential impact of design or control strategy changes. Conveying complex transportation concepts can be effectively achieved by exploring them through simulation. Simulation is particularly valuable in transportation education because most transportation policies and strategies in the real world take years to implement with a prohibitively high cost. Transportation simulation allows learners to apply different control strategies in a risk-free environment and to expose themselves to transportation engineering methodologies that are currently in practice. Despite the advantages, simulation, however, has not been widely adopted in the education of transportation engineering. Using simulation in undergraduate transportation courses is sporadic and reported efforts have been focused on the upper-level technical elective courses. A suite of web-based simulation modules was developed and incorporated in the undergraduate transportation courses at University of Minnesota. The STREET (Simulating Transportation for Realistic Engineering Education and Training) research project was recently awarded by NSF (National Science Foundation) to develop web-based simulation modules to improve instruction in transportation engineering courses and evaluate their effectiveness. Our ultimate goal is to become the epicenter for developing simulation-based teaching materials, an active textbook, which offers an interactive learning environment to undergraduate students. With the hand-on nature of simulation, we hope to improve student understanding of critical concepts in transportation engineering and student motivation toward transportation engineering, and improve student retention in the field. We also would like to disseminate the results and teaching materials to other colleges to integrate the simulation modules in their curricula.

Development of an Online Roadway Geometry Design Software for Transportation Education and Training

Traditionally, students use pencil and ruler to lay out lines and curves over contour maps for roadway geometry design. Numerous calculations of stopping sight distance, minimum turning radius, and curve alignments are required during the roadway design process in order to ensure safety, to minimize economic and environmental impacts, as well as to reduce construction costs. Students usually perform iterative computations manually during the design process in order to meet any given design criteria and environmental constraints. The traditional process of roadway geometry design is often cumbersome and time consuming. The traditional approach limits students from taking a broader perspective of the overall roadway geometry design process. An Internet-based roadway design tool (ROAD: Roadway Online Application for Design) was developed to enhance the learning experience for transportation engineering students. This tool allows students to efficiently design and to easily modify the roadway design with given economic and environmental parameters. A 3D roadway geometry model can be generated by the software at final design to allow students immerse themselves in the driver’s seat and drive through the designed roadway at maximum design speed. This roadway geometry design tool was deployed in a civil engineering undergraduate class in 2006 and 2007 at Department of Civil Engineering, University of Minnesota. Survey results from students indicated the ROAD software enhances their learning experiences in performing roadway geometry design.