Modeling

Prediction of Vehicle Activity for Emissions Estimation Under Oversaturated Conditions Along Signalized Arterials

Skabardonis, Alexander
Geroliminis, Nikolas
Christofa, Eleni
2013

The traditional methodology for estimating vehicle emissions based on vehicle miles traveled and average speed is not reliable because it does not consider the effects of congestion, control devices, and driving mode (cruise, acceleration, deceleration, and idle). The authors developed an analytical model to predict vehicle activity on signalized arterials with emphasis on oversaturated traffic conditions. The model depends only on loop detector data and signal settings as inputs and provides estimates of the time spent in each driving mode, which consequently leads to more accurate...

Oversaturated Freeway Flow Algorithm for Use in Next Generation Simulation

Yeo, Hwasoo
Skabardonis, Alexander
Halkias, John A
Colyar, James
Alexiadis, Vassili
2008

Existing simulation models have difficulty in accurately modeling oversaturated traffic conditions on freeways. A new behavioral algorithm for oversaturated freeway flow can be used in microscopic simulation models; it was developed as part of the Next Generation Simulation (NGSIM) project, sponsored by FHWA. The proposed algorithm is an integrated car-following and lane-changing modeling framework that is consistent with the kinematic wave theory. The algorithm can explicitly model mandatory and discretionary lane changing, including cooperation during lane changing. As an extension of...

Modelling the Traffic Behavior at Grade-Separated Interchanges

Skabardonis, A
Printerhall Limited
Traffic Engineering & Control
1985

Grade separation is an essential feature of intersections between motorways and other high-capacity roads. This paper describes the development of a microscopic simulation model to investigate the interactions between traffic and geometric variables at such situations. The model has been integrated within a modular computer program and it has been calibrated and validated with a large data-base. Comparisons with measured data and information from other sources have shown that the model adequately describes the traffic behaviour. (Author/TRRL)

Improving Average Travel Speeds Estimated by Planning Models

Dowling, Richard
Skabardonis, Alexander
1992

Modeling the impact of air quality requires estimating vehicle volumes and average travel speeds in order to estimate air pollutant emissions. Relatively accurate estimates of average vehicle travel speeds can be obtained from existing traffic operations models. However, when the travel demand impacts of the highway project extend over many miles of the freeway and arterial street network, it is not feasible to apply these detailed traffic operations models to the entire area of impact because of their extensive data requirements. Planners then must resort to areawide planning models to...

Improved Modeling Environment for ATMIS

Skabardonis, Alexander
Lieberman, E B
Menaker, Paul
University of California, Berkeley
KLD Associates Incorporated
Korve Engineering Incorporated
California Department of Transportation
1997

This paper presents a new modeling approach in which the WATSim simulation model is interfaced with dynamic traffic assignment algorithms in order to simulate vehicles with route guidance/information systems. This enhanced model can generate origin-destination and path matrices from observed turning movement counts. It also provides comprehensive statistical, graphical and animation outputs of the vehicle movements. The model was applied to the downtown San Francisco Embarcadero network and is shown to be useful in evaluating the effectiveness of Advanced Traffic Management and Information...

Impacts Assessment of Dynamic Speed Harmonization with Queue Warning

Dowling, R
Skabardonis, A
Barrios, J
Jia, A
Nevers, B
Kittelson and Associates Incorporated
Federal Highway Administration
Department of Transportation
2015

This report assesses the impacts of a prototype of Dynamic Speed Harmonization (SPD-HARM) with Queue Warning (Q-WARN), which are two component applications of the Intelligent Network Flow Optimization (INFLO) bundle. The assessment is based on an extensive analysis of the Prototype using a Vissim simulation model for the US 101 freeway corridor in San Mateo, CA as well as an evaluation of a small-scale demonstration that was conducted in Seattle, WA. Results from the simulation analysis found that the Prototype significantly reduces the magnitudes of the speed drops (shock waves) between...

Guide to Effective Freeway Performance Measurement: Final Report and Guidebook

Margiotta, Richard
Lomax, Timothy J
Hallenbeck, Mark E
Turner, Shawn M
Skabardonis, Alex
Ferrell, Christopher
Eisele, William L
2007

This report examines the effective use of freeway performance measures in operating a freeway system and in meeting the information needs of a large spectrum of potential local, regional, and national users. The guidebook is structured to answer four primary questions about freeway performance: 1) what measures should be used; 2) how can the measures be developed with data and models; 3) how should freeway performance be communicated; and 4) how can freeway performance measures be used in decision making. The report includes detailed step-by-step procedures for addressing these four...

Generalized Hypercube Queueing Model for Locating Emergency Response Vehicles in Urban Transportation Networks

Skabardonis, Alexander
Karlaftis, Matthew G
Geroliminis, Nikolas
Transportation Research Board
2006

Emergency response systems in urban areas should be located in such a way to ensure adequate coverage as well as a rapid response time. We developed a model for locating emergency vehicles on urban networks based on a generalization of the Hypercube Queuing Model. The proposed model considers spatial and temporal characteristics of demand such as the possibility that a server is not always available when its service is required, and the service rates are not identical and may be variable both among servers and incident characteristics. The model is applied for locating tow-away vehicles on...

Freeway Performance Measurement System: Operational Analysis Tool

Choe, T
Skabardonis, A
Varaiya, P
Transportation Research Board
2002

The freeway performance measurement system (PeMS) is a system for all of California. It processes 2 gigabytes/day of 30-s loop detector data in real time to produce useful information. Managers at any time can have a uniform and comprehensive assessment of freeway performance. Traffic engineers can base their operational decisions on knowledge of the current state of the freeway network. Planners can determine whether congestion bottlenecks can be alleviated by improving operations or by minor capital improvements. Travelers can obtain the current shortest route and travel time estimates....

Feasibility and Demonstration of Network Simulation Techniques for Estimation of Emissions in a Large Urban Area

Skabardonis, A
Deakin, Harvey, Skabardonis, Incorporated
1994

The objective of this study was to investigate the possibility of using microscale network simulation computer models to estimate motor vehicle activity for a large urban area. Existing network simulation models are capable of resolving vehicle activity down to the individual vehicle level, and are used to study traffic movements for small areas such as intersections or short sections of highway. Regional travel demand models have historically not been used for the purpose of emissions estimation, and thus poorly define elements of vehicle operation such as accelerations and decelerations...