Abt SRBI conducting first fully GPS-based household travel survey in US

The Ohio Department of Transportation has commissioned Abt SRBI to conduct the nation’s first GPS-based household travel survey. This demonstration project is intended to improve accuracy of trip reporting compared to traditional paper diary methods while reducing respondent burden.

Travel demand forecasting statistically models household travel survey data to generate estimates of household member trips by highway, public transit, and other modes in urban areas. These models are then used for roadway design, development of public transit alternatives, and air quality conformity analyses.

Abt SRBI claims that this ground-breaking project, supported with federal funds, places it in the forefront of advanced transportation research. The approach will also provide for the first time detailed geographic information about trips not captured by traditional interview methods.

Traditionally, household travel surveys have been conducted by recruiting households to complete a paper travel diary one or two travel days and to report that information back over the phone, by mail, or by Internet. This imposes a substantial burden on respondents and has led to poor response rates and often substantial levels of underreported trips.

GPS devices have been used in recent years with small subsets of respondent households to help determine the level of underreporting inherent in the traditional diary-based survey, which has turned out to be substantial. Additionally, while the old bulkier GPS units could only be connected to vehicles, the advanced GPS devices being utilised in this survey can be carried by a person without hardship, hence, it is now possible to capture all trips by an individual person via GPS.

The survey procedures developed by Abt SRBI, and its GPS consultant PlanTrans, involve recruitment of households by phone and Internet, using an address-based sample (ABS) frame within the Greater Cincinnati region. GPS units will be deployed by the Abt SRBI Erlanger, Kentucky office for all members of the household 13 years of age and over. GPS data will be collected for 4,000 households where all members complete tracking for a minimum of three days. An abbreviated paper diary will be utilised for children age 12 and under.

To validate data in this first-of-a-kind effort, 1,500 respondents will receive a follow-up Internet or mail survey which provides a record of their travel for one day. They will be asked to verify trips and stops. Respondents will also be asked for information that will assist in imputing data needed for modelling that cannot be directly collected by GPS, such as trip purpose and mode. An artificial intelligence (AI) programme is being developed by PlanTrans, for this purpose.

This project is being closely monitored by the Survey Methods Committee of the Transportation Research Board, part of the National Academy of Sciences.

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