Nov 25, 2014

The video begins at 0:13.

Classic highway traffic flow theory can explain the evolution of signals and waves once they form. Given sufficient boundary conditions the theory captures the evolution of the traffic state over space and time. But one rarely finds such ideal boundaries on real highways. Often disturbances arise within a region that classic theory would tell us should be homogeneous. These disturbances often grow and give rise to unstable traffic upstream, e.g., resulting in stop-and-go conditions during congestion with an increased frequency of accidents. This talk will examine one potential source of these disturbances, namely the fact that after a lane change maneuver drivers accommodate an entering vehicle quicker than a departing vehicle (mandatory accommodation versus discretionary accommodation). After illustrating this imbalance on two facilities, the talk will explain how it can give rise to lasting disturbances.

Dr. Coifman is an associate professor at the Ohio State University with a joint appointment in the department of Civil and Environmental Engineering and Geodetic Science and the Department of Electrical Engineering. His research emphasizes extracting more information about traffic flow both from conventional vehicle detectors and emerging sensor technologies. His work has been recognized by the ITS America Award for The Best ITS Research and an NSF CAREER award. Dr. Coifman...

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Nov 25, 2014

The video begins at 2:21.

Abstract:

Adaptive signal systems have been deployed in a number of locations across the country though their high maintenance requirements and additional cost have limited their widespread use. Adaptive systems adjust phases and timings at a network of signals in real time to improve traffic operations, particularly along congested corridors.

Rhythm Engineering has developed a new video detection-based system that vastly reduces the cost of deployment and maintenance. However, no existing microsimulation software could model the system due to its innovative methodology.

The methodology involves doing away completely with concept of cycle lengths, splits, and offsets, key parameters use in traffic signal analysis today. HDR and Rhythm Engineering joined together to develop a tool to act as middleware between the adaptive system and VISSIM that would emulate video detection, send the "video" to the adaptive controller, run the adaptive controller algorithm, and transmit detector calls back to VISSIM for inclusion in the model.

This presentation will discuss the lessons learned in the development of the emulation of video detection within VISSIM as well as showing the improvements in traffic operations provided by the system. It will also discuss the implications of the system's architecture and the impact it will have on not only adaptive signal systems...

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Nov 21, 2014

The video begins at 2:00.

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Abstract: Urban arterials often represent complex venues of transportation operations, co-mingling non-motorized users with transit services and a wide variety of land uses and traffic patterns. This presentation presents results related to the evaluation of a new Adaptive Traffic Control System (SCATS) on Powell Boulevard in southeast Portland. The presentation will discuss challenges and opportunities associated with the evaluation of new technologies and the development of comprehensive urban arterial performance measures.

Speaker Bio: Miguel Figliozzi is an Associate Professor of Civil and Environmental Engineering at Portland State University. His diverse research interests include transit and traffic operations, bicycle and pedestrian modes, emissions and air quality modeling, and freight and logistics. He holds a MS from the University of Texas at Austin and a PhD from the University of Maryland College Park. Figliozzi is a member of the Transportation Research Board Network Modeling Committee, Freight and Logistics, and Intermodal Terminal Design Committees. Papers, reports, and more detailed information available at Figliozzi's webpage: http://web.cecs.pdx.edu/~...

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Nov 12, 2014

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This paper uses econometric techniques to examine the determinants of vehicle miles traveled (VMT) in a panel study using data from a cross section of 87 U.S. urban areas over the period 1982-2009. We use standard OLS regression as well as two-stage least squares techniques to examine the impact of factors such as population density, lane-miles per capita, per capita income, real fuel cost, transit mileage, and various industry mix variables on VMT. We use a distributed lag model to estimate the long run elasticity of various factors on VMT driven.

Preliminary empirical results show the demand for VMT in urban areas is positively and significantly impacted by lane miles, personal income, and the percent of employment in the construction. Fuel price, transit use and population density are all found to be negatively related to VMT per capita. Consistent with results from earlier studies, we find the long run price elasticity of demand for VMT per capita is approximately five times larger than the short run elasticity.

Holding all factors constant, per capita VMT is found to differ significantly by region with VMT being higher the more western and the larger the population size of an urban area. Finally, we find that the industry mix or the urban area also has a significant impact on driving.

Nov 12, 2014

PSU Special Transportation Seminar:

An analytical derivation of the capacity at weaving sections consistent with empirical observations and micro-simulated results

Where: ITS Lab, Room 315, PSU Engineering Building

Summary: Weaving sections are discontinuities of the highway network formed when merge segments are closely followed by diverge segments. Because of their geometrical configuration, weaving areas generate numerous lane changes. Those lane changes lead to a reduction of the capacity and affect therefore the operation of weaving sections. 

This contribution aims at investigating empirically the lane changing behavior at a weaving section located in Grenoble (France). The data have been collected at a microscopic level, describing the position of every vehicle at every time step (trajectories of each individual vehicle). The data have been measured with a high-resolution camera mounted underneath a helicopter. 

From the empirical results, we develop an analytical formulation of the capacity of weaving sections. We consider a theoretical weaving section as the superposition of two merges and two diverges. We assume moreover that the accelerations and slowdowns of weaving vehicles create voids in the traffic stream that reduce the total capacity. The analytical estimation of the capacity is compared with field macroscopic data measured in Grenoble and micro-simulated results.

The specification of the needed data sample to...

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Nov 12, 2014

The video begins at 3:12.

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Summary: Real-world traffic trends observed in PORTAL and INRIX traffic data are used to expand the performance measures that can be obtained from Portland Metro's travel demand model to include the number of hours of congestion that can be expected during a typical weekday and travel time reliability measures for congested freeway corridors.

Bio: Michael Mauch, a senior data analyst and project manager with DKS Associates, has over 20 years of experience in transportation data analysis, applications programming, mathematical model building and transportation demand forecasting.  Over the years, Mike has been project manager and has led the technical analyses for numerous large transportation data collection and data analysis projects including BRT and rail transit studies, CIP updates, transportation corridor studies, trip and parking generation studies, corridor capacity analysis, General and Master Plan Updates, incident management cost effectiveness analysis and numerous EIRs. In addition to working with DKS, Mike currently holds a variable-time position as a Research Engineer with UC Berkeley’s Institute of Transportation Studies.  He has taught “Traffic Flow Theory”, “Transit Operations”, and “Computer Programming & Numerical Methods” classes at UC Berkeley, UC Davis and...

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