2013 Session: 766

• Freeway Travel Time Information in Real Time: New Opportunity for Spot Speed Methods
  Abstract: This paper shows that the precision of a freeway travel time information system, in a real-time context, is not related solely to the accuracy of the measurement. Immediacy in reporting the information and forecasting capabilities play a role. Therefore, focusing only on the accuracy of the travel time measurement is a myopic approach, which can lead to counterintuitive results.Specifically, it is claimed that using travel times estimated with the traditional spot speed Midpoint algorithm, the performance of the real-time information system is better than by using much more accurate directly measured travel times. Guidelines for an adequate configuration of the common parameters of the system are provided. These are addressed by taking into account an easy and practical implementation. They have been proven to work well in an empirical application on a Spanish Freeway.
  Authors: Soriguera, Francesc
  Authors: Soriguera, Francesc
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-3743
• Standardized Data Processing: Where We Need It in Mining Private-Sector Probe-Based Traffic Data for Highway Performance Measurement
  Abstract: Reporting highway performance regarding congestion and reliability is required by the newly enacted transportation law of the United States – MAP-21. With unprecedented coverage and details, the private sector probe-based traffic data is among the most promising sources to establish a highway performance monitoring system that can track congestion and reliability on a national scale. But having the data itself is not enough – there are many variants in the data and data processing procedures that can result in significantly different results even based on the same set of data. As demonstrated in this paper, the space mean speed feature of probe data, segment location referencing, different data archiving frequencies, different calculation procedures, and the difference between experienced travel time and instantaneous travel time could all play a role in determining the values of certain performance measures. Standardized data elements and data processing procedures should be established in the effort of using proprietary probe data for highway performance measurement.
  Authors: Pu, Wenjing
  Authors: Pu, Wenjing
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-4242
• Evaluation of Alternative Technologies to Estimate Travel Time on Rural Interstates
  Abstract: New technologies are becoming more and more readily available to collect vehicular traffic data in a cost-effective and non-intrusive fashion. The primary objective of this paper is to present the results of an evaluation of alternative technologies to estimate travel time along a segment of Interstate 91 in Western Massachusetts where traffic volumes and corresponding sample sizes are expected to be relatively low. The first means of data collection uses global positions system technology (GPS) technology employed by INRIX, an enterprise that provides traffic-related information including travel time, directions, and other driver services. The second means uses Bluetooth technology and field data collected by another vendor, BlueTOAD, along the I-91 study site. A third means of data collection using a license plate based method was devised by the authors to provide “ground truth” travel time against which the results of the above two technologies were compared and evaluated. The data analysis showed that sufficient sample sizes were collected and that the accuracy of travel times estimated from data provided by both vendors (i.e., GPS-based INRIX and Bluetooth-based BlueTOAD) is acceptable since their mean absolute percentage errors (MAPE) were consistently less than 6 percent.
  Authors: Jia, Chaoqun; Li, Qiao; Oppong, Samuel; Ni, Daiheng; Collura, John; Shuldiner, Paul W.
  Authors: Jia, Chaoqun; Li, Qiao; Oppong, Samuel; Ni, Daiheng; Collura, John; Shuldiner, Paul W.
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-3892
• Travel Time-Based Freeway Flow Estimation: Case of Two-Detector Problem
  Abstract: In this paper, a special case of two detector problem is considered. Given counts at one end of a segment and segment travel times, it is desired to estimate counts at the other end of the segment. Solution to this problem can be helpful in monitoring health of counting stations. Also, it can potentially produce count estimates at points where no count stations exist. Based on the smoothness assumptions and first-in first-out (FIFO) principle a well-known result is manipulated to solve the problem. Proposed solution consists of a lag one linear filter on the known counts time series in which the weight factors are a function of travel times. In deriving these solutions a distinction between anticipative and retrospective travel times are made. Anticipative travel times are used to estimate upstream counts, and retrospective travel times are used to estimate downstream counts. A two week long count dataset on a segment of I-295 (Anacostia freeway) in the District of Columbia is used to evaluate the performance of the proposed method. A discussion on the accuracy and quality of solutions and directions of future work in this area is provided.
  Authors: Farokhi Sadabadi, Kaveh; Hamedi, Masoud; Haghani, Ali
  Authors: Farokhi Sadabadi, Kaveh; Hamedi, Masoud; Haghani, Ali
  Year: 2013
  Document Type: Paper
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-5296
• Freeway Travel Time Information in Real Time: New Opportunity for Spot Speed Methods
  Authors: Soriguera, Francesc
  Authors: Soriguera, Francesc
  Year: 2013
  Document Type: Presentation
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-3743
• Evaluation of Alternative Technologies to Estimate Travel Time on Rural Interstates
  Authors: Jia, Chaoqun
  Authors: Jia, Chaoqun
  Year: 2013
  Document Type: Presentation
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-3892
• Standardized Data Processing: Where We Need It in Mining Private-Sector Probe-Based Traffic Data for Highway Performance Measurement
  Authors: Pu, Wenjing
  Authors: Pu, Wenjing
  Year: 2013
  Document Type: Presentation
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-4242
• Travel Time-Based Freeway Flow Estimation: Case of Two-Detector Problem
  Authors: Farokhi Sadabadi, Kaveh
  Authors: Farokhi Sadabadi, Kaveh
  Year: 2013
  Document Type: Presentation
  Subject: Data and Information Technology
  Session: 766
  Paper Number: 13-5296