Data Fusion For Delivering Advanced Traveler Information Services
U.S. Department of Transportation
Intelligent Transportation Systems Joint Program Office
Technical Report Documentation Page
1. Report No.
2. Government Accession No.
3. Recipient's Catalog No.
4. Title and Subtitle
Data Fusion for Delivering Advanced Traveler Information Services
5. Report Date
6. Performing Organization Code
David Keever, Motoko Shimizu, and Jennifer Seplow
8. Performing Organization Report No.
9. Performing Organization Name and Address
Science Applications International Corporation
7990 Science Applications Court
Vienna, Virginia 22182
10. Work Unit No. (TRAIS)
11. Contract or Grant No.
12. Sponsoring Agency Name and Address
Federal Highway Administration
ITS Joint Program Office
400 Seventh Street, SW
Washington, D.C. 20590
13. Type of Report and Period Covered
14. Sponsoring Agency Code
15. Supplementary Notes
Sponsoring Agency task Manager – James Pol (202) 366-4374
Many transportation professionals have suggested that improved ATIS data fusion techniques and processing will improve the overall quality, timeliness, and usefulness of traveler information.
The purpose of this study was four fold. First, conduct a literature review of the ATIS and data fusion fields in order to summarize current ATIS data fusion practices. The review also included an examination of relevant field case studies and discussions with selected ATIS practitioners to determine the extent and direction of their data fusion interests and applications. Second, develop an appropriate ATIS data fusion model and guidelines to enable a multitude of source data to be fused to create ATIS products and services, consistent with the National ITS Architecture. Third, identify appropriate metrics that describe quantitatively and qualitatively how data quality can be verified, modeled, and processed so that traveler information products can be considered more reliable and useful. Fourth, provide general guidelines on the development of an ATIS data fusion system.
This report is intended for surface transportation professionals who have an interest in the planning and deployment of ATIS data fusion systems.
17. Key Word
Data fusion, Advanced Traveler Information Services, Intelligent Transportation Systems, National ITS Architecture
18. Distribution Statement
19. Security Classif. (of this report)
20. Security Classif. (of this page)
21. No. of Pages
Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
Advanced Traveler Information System (ATIS) is one of several Intelligent Transportation System (ITS) technologies that offers users integrated traveler information before and during travel, thereby providing a wider range of choices about how, when, and where to travel based on individual interests and needs. One of the major reasons ATIS services has garnered public and professional interest is the concern created by the continuing disparity between the growth in surface transportation travel demand and the relatively minor addition of travel capacity. This combination has resulted in increased regional roadway congestion, greater uncertainty in travel time estimates, and higher real or perceived costs in safety and productivity. Increasing transportation capacity by building roads and other related infrastructure is not a feasible solution in many urban areas due to the high costs as well as environmental and associated societal concerns. Alternative solutions are necessary.
To be effective, ATIS systems must work with a broad set of source data and information, combine and qualify the information to yield better traveler information, and disseminate the information when needed by travelers. One component of this complex process is data fusion.
The purpose of ATIS data fusion is to combine data (in the broadest sense of the term) to estimate or predict the state of some aspect of the surface transportation world. These estimates may include statements about current or future vehicular speeds, mean speeds, vehicular classifications and volumes on selected roadway segments, environmental information, transit system performance, and similar topics of interest to travelers.
The overall effectiveness of data fusion needs to be evaluated in a systems context, taking into consideration the overarching system mission and purpose, architectures, data processing capabilities, data validation and verification, human-system interface, and institutional arrangements. A study was completed, examining these issues, the findings of which can be found in this report. The process of the study was three fold. First, a literature review was conducted of the ATIS and data fusion fields to examine current practices. The review also included an examination of relevant field case studies and discussions with selected ATIS practitioners to determine the extent and direction of their data fusion interests and applications. Second, an appropriate ATIS data fusion model was developed, along with guidelines to enable a multitude of source data to be fused to create ATIS products and services. The model describes ATIS data fusion using five distinct levels of functional activities. Third, appropriate metrics were identified that describe quantitatively and qualitatively how data quality can be verified, modeled, and processed so that traveler information products can be considered more reliable and useful.
The major findings that arose from this study include:
A general awareness of ATIS data fusion and its purpose exists.
The general public, and travelers in particular, are predisposed to use better travel information, although it is unclear under what business model and range of products and services.
Data fusion conducted at transportation and environmental public agencies involves basic fusion functions such as spatial or temporal alignment of input data. Assessments of ATIS services at selected Metropolitan Model Deployment Initiative sites and Field Operational Test sites indicate positive support and public benefits.
Third-party ISPs perform additional data fusion activities, but the specific techniques, accuracy, and usefulness are not readily discernable due to proprietary restrictions.
Two general perspectives exist for ATIS data fusion: a data-centric view and a model-centric view. These perspectives are not mutually exclusive.
Agencies are migrating to the use of the NTCIP and associated data element and message set standards, but will likely initiate their use based on industry acceptance and agency confidence in their utility and longevity.
Data quality policies and procedures are not comprehensive. Practices are limited primarily to “find and fix” tactics on the more egregious data elements.
The findings point out the need for a more comprehensive ATIS data fusion methodology that would allow for increased cross-disciplinary communication and research sharing. A proposed ATIS data fusion model, based on the JDL process model, was offered to help bridge this gap. Moreover, specific data fusion techniques, appropriate for the ATIS context were identified and qualitatively assessed using multiple criteria such as ease of implementation and potential usefulness.
General guidelines for data fusion architectures are presented in the report. The wide variety and combination of ATIS fusion applications and associated architectural components do not allow for a prescriptive, detailed definition of architectural components and fusion techniques. This prescription is best handled through a more structured, system engineering (SE) process involving all stakeholders and design experts. Key elements of the SE process are outlined.
Input data quality continues to be a hindrance to the offering of more advanced ATIS services. Current practices focus on “fix and find” methods without long-term, systemic attention to data quality issues. One of the key issues is the different perspective held by stakeholders on the level of satisfaction with the existing data quality and the associated remedies and costs to make improvements. Greater awareness and understanding of the issues are needed before prescribing remedial action, if any. Resolution of data quality issues will require partnerships among the data owners and users to reach a shared solution.
The report concludes with proposed future actions for enhancing ATIS data fusion practices, summarized into three categories: technological, institutional, and economic opportunities.
Table of Contents
Section 1 Introduction 1
1.1 ATIS Concepts 2
1.2 General Concepts of Data Fusion 5
1.3 Opportunities and Challenges of ATIS Data Fusion 7
1.4 Section 1 References 7
Section 2 Study Approach 1
2.1 Study Objectives 1
2.2 Study Approach 2
Section 3 ATIS Concepts, Trends, and Directions Affecting Data Fusion 1
3.1 Summary of Literature Review and Selected Interviews 1
3.2 Key Findings and Implications for ATIS Data Fusion Development 23
3.3 Section 3 References 24
Section 4 Data Fusion Framework for ATIS Analysis and Implementation 1
4.1 Key Functions To Be Performed In An ATIS Data Fusion System 1
4.2 Data Fusion Model Applicable to ATIS 2
4.3 Data Fusion Architectures 25
4.4 Data Quality Management And Assessment 31
4.5 Section 4 References 33
Section 5 Implementing Data Fusion for ATIS 1
5.1 Development Of ATIS Data Fusion Systems 1
5.2 Data Fusion Algorithm Selection 3
5.3 Section 5 References 5
Section 6 Areas For Future Study and Activities 1
6.1 Study Summary and Conclusions 1
6.2 Future Opportunities and Activities 2
Data Fusion References 40
General ATIS References
Data Fusion References
Data Quality References
Model Deployment Initiatives and Field Test References
List of Figures
Figure 1‑1 Greater Roadway Congestion Has Generated Increased Interest in
Advanced Traveler Information Systems (ATIS) ___________________________ 1-1
Figure 1‑1 Greater Roadway Congestion Has Generated Increased Interest in vii
Figure 1‑2 Greater Roadway Congestion Has Generated Increased Interest in Advanced Traveler Information Systems (ATIS) 1
Figure 1‑3 Informal Illustration of Sources and Uses of ATIS Information 2
Figure 1‑4 The Range of Dynamic Traveler Information Services 4
Figure 1‑5 A Generalized Model of ATIS Functions and ServicesError: Reference source not found 5
Figure 3‑6 A Simplified Structured Analysis Model of ATIS Data Fusion 2
Figure 3‑7 Data Fusion Draws From And Contributes To A Number of Overlapping Disciplines 12
Figure 3‑8 Data Centric and Model-Centric ATIS Data Fusion Activities 14
Figure 4‑9 A Data Fusion Model Applicable to ATIS 4
Figure 4‑10 Levels Of Object Identification 11
Figure 4‑11 The Major Techniques Appropriate For ATIS Object Identification (Level 1) 12
Figure 4‑12 The Relative Merits of Level 1 Data Fusion Techniques 21
Figure 4‑13 Data Quality Categories, Dimensions, And Techniques for Assessing 32
Figure 5‑14 Major Process Steps For Developing An ATIS Data Fusion System 2
Figure 5‑15 A Systematic Approach for Selection and Testing of A Data Fusion Algorithms 4
ATIS Advanced Traveler Information System
AVI Automatic Vehicle Identification
AVL Automatic Vehicle Location
CATV Cable Television
CVO Commercial Vehicle Operations/Operator
CORBA Common Object Request Broker Architecture
DATEX-ASN.1 DATa Exchange in Abstract Syntax Notation One
DMS Dynamic Message Signs
FHWA Federal Highway Administration, USDOT
FOT Field Operational Test
FTP File Transfer Protocol
GPS Global Positioning System
HAR Highway Advisory Radio
HTML HyperText Markup Language
IEEE Institute of Electrical and Electronics Engineers
IM Incident Management
ISP Internet Service Provider
ITS Intelligent Transportation Systems
IVR Interactive Voice Recognition
JDL Joint Directors of Laboratories (U.S. government laboratories)
MMDI Metropolitan Model Deployment Initiative
NTCIP National Transportation Communications for Intelligent Transportation System Protocols
PDA Personal Digital Assistant
RAID Redundant Array of Inexpensive Disks
RFID Radio Frequency Identification
SDO Standard Development Organization
SE Systems Engineering
SNMP Simple Network Management Protocol
SQL Structured Query language
STMP Simple Transportation Management Protocol
TFTP Trivial File Transfer Protocol
TMC Traffic Management Center
USDOT United States Department of Transportation
VMS Variable Message Signs
W3C World Wide Web Consortium
WIM Weigh In Motion
WWW World Wide Web
XML Extensible Markup Language