February 2012

Friday Seminar - Anthony Evans on Simulating Airline Operational Responses to Environmental Constraints

Submitted by ITSLibrary on Mon, 2012-02-27 09:53
in

Airliner

This week’s Friday TRANSOC Seminar has Anthony Evans, Postdoctoral Fellow, NASA Ames Research Center, presenting “Airline Operational Responses to Environmental Constraints.”

Significant growth is anticipated in global air transportation over the coming decades, which is expected to have local and global environmental impacts. This presentation describes a model that predicts airline flight network, frequency and fleet changes in response to policy measures that aim to reduce the environmental impact of aviation. Such airline operational responses to policy measures are not considered by most integrated aviation-environment modelling tools. By not modelling these effects the capability of the air transport system to adjust under changing conditions is neglected, resulting in the forecasting of potentially misleading system and local responses to constraints.

 

Friday Seminar - Vikash Gayah on The Aggregate Effect of Turns on Urban Traffic Networks

Submitted by ITSLibrary on Wed, 2012-02-22 09:57
in

overland ave traffic

This week’s Friday TRANSOC Seminar has Vikash Gayah, Ph.D. candidate, University of California, Berkeley, presenting “The Aggregate Effect of Turns on Urban Traffic Networks.” 

This research creates and uses macroscopic traffic models to describe the aggregate behavior of vehicles on urban street networks. Insights gained from these models can then be used to design network-wide policies that may increase the ability of these networks to serve vehicle-trips. In particular, this work focuses on the turning maneuvers that exist in networks with multiple routes. The presence of multiple routes and turning maneuvers are found to have two effects on aggregate vehicle behavior: 1) they cause unstable and inefficient behavior when a network is congested; and, 2) they may reduce maximum vehicle flows across the network. Fortunately, this work finds that limiting the rate at which vehicles are allowed to enter a network and providing drivers with real-time information on current traffic conditions can help mitigate the first effect and allow the network to operate more efficiently. It is also found that the second effect may not always be harmful—lower network flows do not necessarily result in decreased network efficiency if the lower flows are accompanied by more direct vehicle routing. In fact, two-way networks, which accommodate conflicting left-turns and result in lower maximum vehicle flows than one-way networks, are found to serve trips at a higher rate because drivers travel shorter distances on average. Thus, in many cities, maximum network efficiency can be improved by converting one-way streets to two-way operation.

The seminar will take place at 4:00 PM in534 Davis Hall. Please join us for a TRANSOC-sponsored Cookie Hour in the ITS Library at 3:30 PM.

Friday Seminar - Lily Elefteriadou on Driver Behavior and Characteristics and Their Use in Traffic Modeling

Submitted by ITSLibrary on Tue, 2012-02-14 09:31
in

Driver Experience @ Limeira

This week's Friday TRANSOC Seminar has Lily Elefteriadou, Professor and Director of the Transportation Research Center, School for Sustainable Infrastructure and the Environment, University of Florida, presenting “Driver Behavior and Characteristics and Their Use in Traffic Modeling.” 

Traffic modeling has frequently considered and accounted for variability in driver behavior and characteristics.  For example, microscopic traffic simulators have the capability to replicate vehicular movements (such as lane changing) considering driver characteristics to a significant level of detail.  Such traffic simulators can typically replicate traffic streams with several different driver types which are based on driver aggressiveness.  Vehicular movements (such as car following) are then determined based on the respective action of the particular driver type.  However, a limited amount of research has been reported to categorize driver types or to link particular driving actions with a set of driver types and their characteristics.  Car-following, lane changing, and gap acceptance algorithms have rarely been calibrated to match various driver types, and it is not always clear how micro-simulators incorporate driver behavior aspects into these algorithms.  This presentation will describe two approaches to collecting driver behavior and characteristics-related data so that they can be used to improve traffic micro-simulators.  The first approach is based on focus groups, while the second is based on in-vehicle field data collection with an instrumented vehicle.  The presentation will describe these two data collection approaches and will provide three example applications related to freeway merging, car-following, and arterial lane changing. 

Friday Seminar - Elizabeth Deakin on BART State of Good Repair: What It Will Take to Maintain The System

Submitted by ITSLibrary on Wed, 2012-02-08 09:35
in

200408 bart carriage

This week's Friday TRANSOC Seminar has Elizabeth Deakin, JD, Professor, City and Regional Planning and Urban Design, University of California, Berkeley, presenting "BART State of Good Repair: What It Will Take to Maintain the System."

The Bay Area Rapid Transit (BART) system is approaching 40 years of service, and BART is preparing for a large reinvestment program, including replacing overage vehicles and aging infrastructure to keep BART in a state of good repair (SGR).  However, some of the funding for this program is uncertain and therefore it is possible that some of the planned investment in the replacement of equipment and infrastructure will have to be deferred.  This presentation examines the levels and types of investment needed to maintain BART in a state of good repair, identifies the kinds of deterioration in BART services that are likely if less money is available for SGR than needed, evaluates how service deterioration would affect BART ridership, and assesses the consequences for the Bay Area’s transportation system, the economy, and the environment.  Stakeholder perspectives on funding for SGR also are investigated.

Friday Seminar - Tasos Kouvelas on Adaptive Fine-tuning for Large-scale Nonlinear Traffic Control Systems

Submitted by ITSLibrary on Fri, 2012-02-03 09:14
in

Traffic Light Tree

This week’s Friday TRANSOC Seminar has Tasos Kouvelas, Ph.D., Postdoctoral Researcher, University of California, Berkeley, presenting  “Adaptive Fine-tuning for Large-scale Nonlinear Traffic Control Systems.”

This talk introduces and analyzes a new learning/adaptive algorithm that enables automatic fine-tuning of Large-scale Nonlinear Traffic Control Systems (LNTCS), so as to reach the maximum performance that is achievable with the utilized control strategy. LNTCS have many applications in transportation, as with urban signal control or ramp metering, and yet their efficient design and deployment remains elusive due to the involved complexity and nonlinearities. Often, the deployment of a new algorithm (or the updating of an existing one) requires extensive fine-tuning before it reaches its best achievable performance. Typically, this fine-tuning procedure is conducted manually, via trial-and-error, relying on expertise and human judgment and without the use of a systematic approach. The proposed Adaptive Fine Tuning (AFT) algorithm is aiming at replacing the conventional manual optimization practice with a fully automated online procedure. The talk provides a detailed analysis of the algorithm as well as a step-by-step application description. Finally, application results of the algorithm to real-time fine-tuning problems of general LNTCS are presented using the commercial micro-simulation tool AIMSUN.

The seminar will take place today 4:00 PM in 406 Davis Hall. Please join us for a TRANSOC-sponsored Cookie Hour in the ITS Library at 3:30 PM.