Data

Updates to CalME and Calibration of Cracking Models

Wu, Rongzong
Harvey, John
Lea, Jeremy
Angel Mateos
Yang, Shou
Hernandez, Noe
2021

The CalME flexible pavement simulation and design software program has been completely recoded as a web-based application calledCalME 3.0. CalME 3.0 retains the same incremental-recursive damage approach and the same forms for damage models and transferfunctions as CalME 2.0, which was validated using accelerated pavement testing data from Heavy Vehicle Simulator (HVS) test sectionsand the WesTrack experiment.The following enhancements and additions are all included in the revised program. First, the old software’s fatigue cracking transferfunctions for hot mix asphalt (HMA) on aggregate...

Data-Driven Energy Use Estimation in Large Scale Transportation Networks

Wang, Bin
Chan, Cy
Somasi, Divya
Jane Macfarlane
Rask, Eric
2019

Energy consumption in the transportation sector accounts for 28.8% of the total value among all the industry sectors in the United States, reaching 28.2 quadrillion btu in 2017. Having an accurate evaluation of the vehicle fuel and energy consumption values is a challenging task due to numerous implicit influential factors, such as the variety of powertrain configurations, time-varying traffic and congestion patterns, and emerging new technologies, such as regenerative braking. In this paper, we propose to present a data-driven computational framework to evaluate the energy impact on the...

Mobile Device Data Analytics for Next-Generation Traffic Management

Jane Macfarlane
Patire, Anthony, PhD
Deodhar, Kanaad
Laurence, Colin
2021

Quality data is critically important for research and policy-making. The availability of device location data carrying rich, detailed information on travel patterns has increased significantly in recent years with the proliferation of personal GPSenabled mobile devices and fleet transponders. However, in its raw form, location data can be inaccurate and contain embedded biases that can skew analyses. This report describes the development of a method to process, clean, and enrich location data. Researchers developed a computational framework for processing large scale location datasets....

A Data-Centric Weak Supervised Learning for Highway Traffic Incident Detection

Sun, Yixuan
Mallick, Tanwi
Balaprakash, Prasanna
Jane Macfarlane
2022

Using the data from loop detector sensors for near-real-time detection of traffic incidents on highways is crucial to averting major traffic congestion. While recent supervised machine learning methods offer solutions to incident detection by leveraging human-labeled incident data, the false alarm rate is often too high to be used in practice. Specifically, the inconsistency in the human labeling of the incidents significantly affects the performance of supervised learning models. To that end, we focus on a data-centric approach to improve the accuracy and reduce the false alarm rate of...

Differential Privacy in Aggregated Mobility Networks: Balancing Privacy and Utility

Haydari, Ammar
Chuah, Chen-Nee
Zhang, Michael
Jane Macfarlane
Peisert, Sean
2024

Location data is collected from users continuously to understand their mobility patterns. Releasing the user trajectories may compromise user privacy. Therefore, the general practice is to release aggregated location datasets. However, private information may still be inferred from an aggregated version of location trajectories. Differential privacy (DP) protects the query output against inference attacks regardless of background knowledge. This paper presents a differential privacy-based privacy model that protects the user's origins and destinations from being inferred from aggregated...

A Machine Learning Method for Predicting Traffic Signal Timing from Probe Vehicle Data

Ugirumurera, Juliette
Severino, Joseph
Bensen, Erik A.
Wang, Qichao
Jane Macfarlane
2023

Traffic signals play an important role in transportation by enabling traffic flow management, and ensuring safety at intersections. In addition, knowing the traffic signal phase and timing data can allow optimal vehicle routing for time and energy efficiency, eco-driving, and the accurate simulation of signalized road networks. In this paper, we present a machine learning (ML) method for estimating traffic signal timing information from vehicle probe data. To the authors best knowledge, very few works have presented ML techniques for determining traffic signal timing parameters from...

Uncertainty Quantification for Traffic Forecasting Using Deep-Ensemble-Based Spatiotemporal Graph Neural Networks

Mallick, Tanwi
Jane Macfarlane
Balaprakash, Prasanna
2024

Deep-learning-based data-driven forecasting methods have achieved impressive results for traffic forecasting. Specifically, spatiotemporal graph neural networks have emerged as a promising class of approaches because of their ability to model both spatial and temporal patterns in traffic data. A major limitation of these methods, however, is that they provide forecasts without estimates of data and model uncertainty, which are critical for understanding inherent variations of the data and forecast limitations due to a lack of training data. We develop a scalable deep ensemble approach to...

Cost Economics of Aircraft Size

Wei, Wenbin
Mark Hansen
1993

The authors study the relationship between aircraft cost and size for large commercial passenger jets. Based on a translog model, they develop an econometric cost function for aircraft operating cost and find that economies of aircraft size and stage length exist at the sample mean of their data set, and that for any given stage length there is an optimal size, which increases with stage length. The scale properties of the cost function are changed considerably if pilot unit cost is treated as endogenous, since it is correlated with size. The cost-minimising aircraft size is therefore...

Demand and Consumer Welfare Impacts of International Airline Liberalization: The Case of the North Atlantic

Maillebiau, Eric
Mark Hansen
1993

Impacts of international airline bilateral liberalization on demand, fares, accessibility, and consumer welfare in the North Atlantic are studied, based on data for markets between the United States and five European countries. A demand model, estimated at the country-pair level, suggests that demand is slightly fare inelastic (e ~= -0.9), and that demand has responded positively, though inelastically (e~=0.2), to changes in accessibility (A measure of how much non-stop service is available). A yield model is estimated to assess the impact of bilateral liberalization status on fares, and...

Integrated Air Freight Cost Structure: The Case of Federal Express

Kiesling, Max K.
Mark Hansen
1993

This paper analyzes the economic structure of the integrated air freight industry. We evaluate a total cost model for Federal Express, Inc. by analyzing quarterly time-series data from 1986-1992. We find that Federal Express, and arguably all dedicated air freight carriers, exhibit diseconomies of scale and significant economies of density. We show that these two economic concepts can be restrictive, however, and introduce a third aspect of the integrated air freight industry’s economic structure that combines the effects of economies of density and economies of scale. We call it economies...