NCHRP Project 08-36
Proposed Research Problem Statement
1.
Title
Analysis Methods of GPS Travel Data
2.
Background
Models of traveler behavior have been used to forecast demand for transportation facilities since the 1950s. Traditionally, diary-based household travel surveys were the foundation of these travel demand models, but the advancement of GPS technology has allowed for paper diaries to be replaced by personal GPS units. However, a great deal of post-processing of the
GPS data is required to derive the information necessary for analysis and model estimation.
In the absence of a standard procedure, a number of different methods have been used to identify trip ends, destinations, mode, and purpose from the GPS data stream. A lack of guidelines or documentation of available methods and assumptions makes it difficult to fully understand any limitations associated with the final processed dataset.
3.
Statement of Urgency
In 2008, the Ohio Department of Transportation funded the first large-scale GPS-only household travel survey. Since then, New York City, Caltrans, Georgia DOT and Cleveland have either conducted or contracted to conduct GPS travel surveys. As these data will be used to develop travel models starting in fall 2011, the documentation of the existing methods and their guidelines for use is timely.
4.
Project Objective(s)
The objective of this project is to define standards and guidelines for documenting GPS travel data processing procedures and data structures.
5.
Relationship to Existing Body of Knowledge
To date, overviews of existing procedures have been reported at the TRB annual meetings.
However, reports have not been detailed and much has focused on the identification of nonmotorized travel. While work has been completed by PlanTrans, GeoStats, the University of
Illinois at Chicago and others, details regarding the actual algorithms, methods, assumptions and level of effort (manual vs. automated) has not been well documented. Guidelines and limitations of mainstream use have not been published.
6.
List of Anticipated Work Tasks
Review the different methods, techniques and result of current efforts of post-processing of
GPS survey data for personal transport. This review should be comprehensive and include

algorithms (both proprietary and open-source), models, data cleaning processes, supplementary data needs, data accuracy, data comprehensiveness, and reliability of estimates for various characteristics of trips and tours including activity spaces. It should also account for the effects of factors such as positional quality of underlying transportation network to match GPS points (map matching). It may also include a discussion of the feasibility and benefits of linking post-processed GPS survey data with data from other survey methods such as pen and paper, telephone-based, and internet-based prompted recall approaches. Information should be gathered by literature review, surveys of academics, consultants, and MPOs, and selected interviews. The report should also include brief case studies illustrating successful practices.
7.
Estimate of Funds Needed
$100,000
8.
Estimate of Time Needed to Complete the Research
1 year
9.
Name, Affiliation and Contact Information of Submitter(s)
Rebekah Anderson, P.E.
Office of Statewide Planning and Research
Ohio Department of Transportation
614-752-5735 rebekah.anderson@dot.state.oh.us
Elaine Murakami
FHWA Office of Planning
202-220-4460 elaine.murakami@dot.gov
10.
Date of Submittal
3/31/2011