Cross-cutting Issues

Over the past five years, the City of Los Angeles Department of Transportation (LADOT) has been testing and deploying new parking technology in an effort to improve customer service, reliability, and efficiency, while providing staff the tools necessary to begin the intelligent management of parking in Los Angeles. Through the deployment of wirelessly-connected sensors, parking meters, and pay stations in select areas of the City, parking management staff is routed directly to maintenance and enforcement needs, and customers can find the closest available parking, all in real-time. This new parking technology is now set to blanket all of Downtown Los Angeles, and, combined with an intelligent parking management system, become an innovative congestion management tool through demand-based parking pricing and a comprehensive parking guidance system.

City of Los Angeles DOT

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

This study develops two on-line stochastic routing policies/algorithms which identify the optimal next action at the current decision node (intersection) for travelers preferring either the shortest path or the most reliable path given the current network conditions. Considering that real-time traffic information is usually available with a certain level of accuracy, the proposed on-line routing policy integrates an existing information fusion model which provides real-time short-term link travel time distributions by considering information accuracy. Further, this study uses numerical experiments to demonstrate the efficiency of the proposed routing policies/algorithms as well as the impacts of realtime information accuracy on the on-line stochastic routing.

NEXTRANS

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

Reliable estimates of conditions on arterials are the holy grail of traffic performance measurement.  The Chicago Arterial Performance Measurement System was developed by Chicago DOT and the Chicago Transit Authority to cost effectively monitor traffic conditions on arterials.  CAPMS gathers and processes real-time performance data using existing infrastructure and innovative technologies to measure traffic congestion on Chicago streets.  Design considerations included network segmentation, associating bus probe GPS data with segments, traffic condition algorithms, travel time estimation procedures, map displays, and modular software architecture.  CAPMS is the analytical and data processing engine that drives the Chicago Traffic Tracker traveler information service.  CAPMS is also a key subsystem in the design of the Chicago Traffic Management Center (TMC) Advanced Traffic Management System.  Current traffic conditions on major arterials are calculated and displayed on roadway segments and for community areas throughout Chicago.

Authors: David Zavattero, Abraham Emmanuel

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The Vehicle Probe Project (VPP) is an outsourced traffic monitoring system established by the I-95 Corridor Coalition and has been active since July 2008. By contractual agreement with the vendor, INRIX Corporation, travel time and speed data are provided to minimum quality specifications whenever traffic flow exceeds 500 vehicles per hour (vph). The monthly validation program has confirmed the quality of the data by comparing VPP data against travel times collected using BluetoothTM traffic monitoring equipment, but typically during high volume periods when congestion is likely. Validation has not been confirmed for minimum flow conditions (less than 500 vph) due in part to lack of accurate volume data as well as the low probability of observing traffic congestion at low volumes. The VPP provides an indication of real-time data by the score attribute. When score is equal to 30, the traffic data is based on real-time information. A score less than 30 indicates reliance on historical data. Studies have shown that traffic data based primarily on historical data do not meet minimum quality specifications during moderate and severe congestion. By using volume data from the Maryland State Highway Administration and the Delaware Department of Transportation from permanent count locations, the likelihood of acquiring real-time data (as evidenced by score equal 30) as a function of hourly volume is established.

Authors: Hadi Sadrasadat, Ph.D., Stanley Ernest Young Ph.D.

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida

The I-95 Vehicle Probe project (VPP) has been in production since July 2008 providing estimates of speed and travel time on network of roadways that has expanded to over 5,000 freeway miles. Each estimate of speed is accompanied by two metrics that provide an indication of the level of confidence and/or quality of the traffic data: Score and C-value. This paper statistically characterizes the distribution of Score and C-Value in the VPP data archive in order to better understand the quality of the VPP and reveal any improvements over the life of the project.  Both Score and C-Value are tested to determine their effectiveness as a data filter to improve real-time traffic data quality.

Authors: Stanley E. Young, P.E., Ph.D., Nayel Urena Serulle

Presented at the 18th World Congress on ITS, October 2011, Orlando, Florida