Intelligent Transportation Systems

Incorporation of Lagrangian Measurements in Freeway Traffic State Estimation

Herrera, Juan C.
Bayen, Alexandre M.
2010

Cell-phones equipped with a global positioning system (GPS) provide new opportunities for location-based services and traffic estimation. When traveling on-board vehicles, these phones can be used to accurately provide position and velocity of the vehicle as probe traffic sensors. This article presents a new technique to incorporate mobile probe measurements into highway traffic flow models, and compares it to a Kalman filtering approach. These two techniques are both used to reconstruct traffic density. The first technique modifies the Lighthill–Whitham–Richards partial differential...

Mobile Millennium: GPS Mobile Phones as Traffic Probes, California Networked Traveler - Safe Trip 21 Phase II

Bayen, Alexander M.
2011

Recent advances in mobile devices and internet technology have led the California Department of Transportation (Caltrans) to investigate a data collection solution that offers improved data reliability and availability at a significantly lower cost. It has been postulated that information from GPS cell phones could provide position and speed data -- referred to as probe data -- for highways and arterials in near real time over much of the transportation network. The Mobile Millennium project was established to determine if the collection and use of probe data for traveler information...

An Adaptive Routing System for Location-Aware Mobile Devices on the Road Network

Borokhov, Paul
Blandin, Sébastien
Samaranayake, Samitha
Goldschmidt, Olivier
Bayen, Alexandre M.
2011

As congestion problems become a greater concern and negatively impact society, solutions which alleviate them are needed to improve the performance of the transportation system. Routing systems which take into account the travel-time experienced by the driver have been largely unexplored in the domain of adaptive routing. In this article, we present a system which enables users of smartphones to obtain directions generated using an algorithm which provides an optimal routing policy for reliable on-time arrival; that is, directions which seek to maximize the probability of arriving to the...

iShake: Mobile Phones as Seismic Sensors -- User Study Findings

Ervasti, Mari
Dashti, Shideh
Reilly, Jack
Bray, Jonathan D.
Bayen, Alexandre
2011

The "iShake" system uses smartphones as seismic sensors to measure and deliver ground motion intensity parameters produced by earthquakes more rapidly and accurately than currently possible. Shaking table tests followed by field trial with approximately 30 iShake users were implemented to evaluate the reliability of the phones as seismic monitoring instruments and the functionality of the iShake system. In addition, user experiences were investigated with 59 iShake users, who provided feedback through a mobile questionnaire. Research included participative planning with a focus group to...

Individual Speed Variance in Traffic Flow: Analysis of Bay Area Radar Measurements

Blandin, Sébastien
Salam, Amir
Bayen, Alexandre
2012

The recent increase of mobile devices able to measure individual vehicles speed and position with high accuracy brings new opportunities to traffic engineers. The large amount of individual probe measurements allows the study of phenomena previously unobservable with conventional sensing technologies, and the design of novel traffic monitoring and control strategies. However, challenges inherent to the use of speed and location data arise. One of the main difficulties of measurements collected from individual vehicles lie in their ability to provide relevant information on the...

A Tractable Class of Algorithms for Reliable Routing in Stochastic Networks

Samaranayake, Samitha
Blandin, Sébastien
Bayen, A.
2012

The goal of this article is to provide the theoretical basis for enabling tractable solutions to the “arriving on time” problem and enabling its use in real-time mobile phone applications. Optimal routing in transportation networks with highly varying traffic conditions is a challenging problem due to the stochastic nature of travel-times on links of the network. The definition of optimality criteria and the design of solution methods must account for the random nature of the travel-time on each link. Most common routing algorithms consider the expected value of link travel-time as a...

Enhancing Privacy and Accuracy in Probe Vehicle-Based Traffic Monitoring via Virtual Trip Lines

Hoh, Baik
Iwuchukwu, Toch
Jacobson, Quinn
Work, Daniel
Bayen, Alexandre M.
Herring, Ryan
2012

Traffic monitoring using probe vehicles with GPS receivers promises significant improvements in cost, coverage, and accuracy over dedicated infrastructure systems. Current approaches, however, raise privacy concerns because they require participants to reveal their positions to an external traffic monitoring server. To address this challenge, we describe a system based on virtual trip lines and an associated cloaking technique, followed by another system design in which we relax the privacy requirements to maximize the accuracy of real-time traffic estimation. We introduce virtual trip...

Reconstruction of Boundary Conditions from Internal Conditions Using Viability Theory

Hofleitner, A.
Claudel, C.
Bayen, A.
2012

This article presents a method for reconstructing downstream boundary conditions to a HamiltonJacobi partial differential equation for which initial and upstream boundary conditions are prescribed as piecewise affine functions and an internal condition is prescribed as an affine function. Based on viability theory, we reconstruct the downstream boundary condition such that the solution of the Hamilton-Jacobi equation with the prescribed initial and upstream conditions and reconstructed downstream boundary condition satisfies the internal value condition. This work has important...

Automatic Inference of Map Attributes from Mobile Data

Hofleitner, Aude
Côme, E.
Oukhellou, L.
Lebacque, Jean-Patrick
Bayen, A.
2012

The development and update of reliable Geographic Information Systems (GIS) greatly benefits Intelligent Transportation Systems developments including real-time traffic management platforms and assisted driving technologies. The collection and processing of the data required for the development and update of GIS is a long and expensive process which is prone to errors and inaccuracies, making its automation promising. The article introduces a method which leverages the emergence of sparsely sampled probe vehicle data to update and improve existing GIS. We present an unsupervised...

Providing In-Vehicle Soft Safety Alerts Using Mobile Millennium Data and Vehicle Event Information

Nowakowski, Christopher
Gupta, Somak Datta
Myers, Scott
Shladover, Steven
Bayen, Alexandre
2012

The Mobile Millennium project provided a platform for aggregating traffic information across various sources, including infrastructure sensors, commercial data feeds, probe vehicles, and probe cell phones. The Networked Traveler project provided the California PATH instrumented research vehicle platform used to both deliver vehicle probe data back to the infrastructure and to generate Advanced Driver Assistance Systems (ADAS) alerts to the drivers of those vehicles. The main theme of this collaboration project was to demonstrate the potential to create Enhanced Probe Vehicles (EPVs) by...