Data

Predicting Lane-by-Lane Flows and Speeds for Freeway Segments

Sasahara, Fabio
Staichak Carvalho, Luan Guilherme
Chowdhury, Tanay Datta
Jerome, Zachary
Elefteriadou, Lily
Skabardonis, Alexander
2020

The Highway Capacity Manual is a major reference for evaluating the capacity and quality of service of road facilities. However, it holds the assumption that lanes perform equally, which can result in inaccuracies in performance estimation. The main purpose of this research is to develop a series of models for estimating flows and speeds by lane for various types of freeway segments, including basic, merge, and diverge types. These models consider the demand-to-capacity ratio, the presence of trucks, grade, and the presence of upstream and downstream ramps. To predict lane performance...

Predicting the Impacts of Intelligent Transportation Systems on Freeway Queue Discharge Flow Variability

Dowling, Richard G
Skabardonis, Alexander
Reinke, David B
2008

This study focuses on the problem of measuring the queue discharge flow rates for a nonbottleneck freeway section and on developing an approach for estimating the impacts of intelligent transportation system (ITS) measures on the mean and variance of the queue discharge flow rate. The whole-year mean and variance of the queue discharge flow rates for the subject section of freeway are computed on the basis of measured 5-min congested flow rates over the course of a year. The flow data are categorized into congested and uncongested flows on the basis of a speed threshold that separates...

Performance Evaluation of Travel-Time Estimation Methods for Real-Time Traffic Applications

Ban, Xuegang Jeff
Li, Yuwei
Skabardonis, Alexander
Margulici, J D
2010

Travel time for an itinerary constitutes one of the most relevant roadway traffic metrics. Numerous studies have been conducted to estimate travel times on the basis of data from loop detectors. This article focuses on evaluating the performance of a set of estimation methods--algorithms that estimate route travel times using specific speed data from dual loop detectors for real-time applications, such as displaying travel times on changeable message signs. The travel-time estimates are evaluated against probe vehicle data obtained from FasTrak in the San Francisco Bay Area to determine...

Performance Evaluation of Travel Time Methods for Real Time Traffic Applications

Ban, Xuegang
Li, Yuwei
Skabardonis, Alexander
Margulici, J D
World Conference on Transport Research Society
2007

Among all forms of traveler information, travel time is regarded as the most critical because it can empower drivers to make more informed decisions and potentially improve the performance of the entire system. Numerous studies have been conducted for predicting travel time based on measured data, mostly from loop detectors. This paper focuses on evaluating the performance of a set of “benchmark” methods designed to utilize loop data to provide route travel times for display on Changeable Message Signs (CMS). The paper reveals that (1) although the “ground-truth” travel time (e.g., those...

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...

Offline Offset Refiner for Coordinated Actuated Signal Control Systems

Yin, Yafeng
Li, Meng
Skabardonis, Alexander
2007

This paper presents the concept and implementation of an offline offset refiner, which addresses the problem of uncertain (not fixed) starts/ends of green in the determination of offsets for coordinated actuated signal control. Making use of a large amount of archived signal status data available from real-time signal operations, the refiner may fine tune the signal offsets to provide smoother progression in either one-way or two-way coordination. The proposed offset refiner is easy to implement and can work readily with current closed-loop signal control systems to improve their system...

On Traffic Flow Regimes and Transitions in Signalized Arterials

Vlahogianni, Eleni I
Geroliminis, Nikolas
Skabardonis, Alexander
Transportation Research Board
2007

The paper presents the formulation and application of a data driven methodological framework to identify traffic flow regimes and transitions on signalized arterials from point measurements of volume and occupancy. The identification of regimes is conducted by a wavelet-based fuzzy clustering approach, while transitional conditions are studied using Bayesian networks. The results from this data-driven approach indicate the existence of four distinct traffic flow regimes; these regimes hold in arterials with different geometric and signalization characteristics. An analytical model is also...

Improved Speed-flow Relationships for Planning Applications

Skabardonis, A
Dowling, R
Transportation Research Board
1997

Improved speed-estimation techniques for planning applications were developed and tested. Comparisons with field data and simulation results indicate that the recommended techniques provide better accuracy and consistency with the procedures contained in the 1994 update of the "Highway Capacity Manual". These speed-estimation techniques will improve the accuracy of long-range transportation planning models for predicting travel time, delay, and air-pollutant emissions.

Impacts Assessment of Dynamic Speed Harmonization with Queue Warning: Task 3, Impacts Assessment Report [supporting dataset]

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

Source: Provided by ITS DataHub (its.dot.gov/data) through the National Transportation Library. The datasets in the .pdf and .zip attached to this record are in support of Intelligent Transportation Systems Joint Program Office (ITS JPO) report FHWA-JPO-15-222, "Impacts Assessment of Dynamic Speed Harmonization with Queue Warning: Task 3, Impacts Assessment Report". The files in these zip files are specifically related to the US-101 Testbed, near San Mateo, CA. The uncompressed and compressed files total 2.0265 GB in size. The files have been uploaded as-is; no further documentation was...

Impacts Assessment of Dynamic Speed Harmonization with Queue Warning: Task 2 Impact Assessment Plan

Dowling, R
Skabardonis, A
Barrios, J
Jia, A
Nevers, B
Kittelson & Associates Incorporated Kittelson &
Federal Highway Administration
Turner-Fairbank Highway Research Center
National Transportation Library
2015

The purpose of the Impact Assessment Plan is to take the results of the test track or field tests of the prototype, make reasonable extrapolations of those results to a theoretical full scale implementation, and answer the following 7 questions related to the prototype: (1) When to Implement SPD-HARM Solo or in Combination with Q-WARN?; (2) Which Communication Method is Best for Nomadic (cell phone) Devices?; (3) What are the Impacts of Near, Mid and Long Term Deployment?; (4) What level of market Penetration of connected vehicles is Required for success?; (5) What are the Effects of...