An analysis of the factors influencing differences in survey-reported and GPS-recorded trips

Abstract

Recent advances in global positioning systems (GPS) technology have resulted in a transition in household travel survey methods to test the use of GPS units to record travel details, followed by the application of an algorithm to both identify trips and impute trip purpose, typically supplemented with some level of respondent confirmation via prompted-recall surveys. As the research community evaluates this new approach to potentially replace the traditional surveyreported collection method, it is important to consider how well the GPS-recorded and algorithm-imputed details capture trip details and whether the traditional survey-reported collection method may be preferred with regards to some types of travel.This paper considers two measures of travel intensity (survey-reported and GPSrecorded) for two trip purposes (work and non-work) as dependent variables in a joint ordered response model. The empirical analysis uses a sample from the full-study of the 2009 Indianapolis regional household travel survey. Individuals in this sample provided diary details about their travel survey day as well as carried wearable GPS units for the same 24-hour period.The empirical results provide important insights regarding differences in measures of travel intensities related to the two different data collection modes (diary and GPS). The results suggest that more research is needed in the development of workplace identification algorithms, that GPS should continue to be used alongside rather than in lieu of the traditional diary approach, and that assignment of individuals to the GPS or diary survey approach should consider demographics and other characteristics.

Quantifying human exposure to air pollution—Moving from static monitoring to spatio-temporally resolved personal exposure assessment

“…In addition to that, not all study participants may be familiar with or keen on using electronic devices. Thus, the application of advanced communication technology may result in anxiety and misuse, potentially limiting the applicability of these methods (Bricka et al, 2012).…”

“…Although functional, there are limits to the general applicability of this methodology due to simplifications and assumptions adopted such as the qualification of indoor activities for which the TAD was used and where the GPS sensor cannot receive a signal. Differences in survey-reported and GPS-reported trips for a 24 hour period were investigated by Bricka et al (2012). Data were selected from the 2009 Indianapolis regional household travel survey.…”

Are young drivers as careful as they deem? In vehicle data recorders and self reports evaluations

“…Retrospective questionnaires (asking about individual trips from the previous week without forewarning) provide comparable estimates, but the overall week mileage estimates were 20-30 % lower than trip by-trip listings in most cases. [19] found large differences between IVDR measurements and similar statistics obtained through SR. Bricka et al [4] reported on a study which considered two measures of travel intensity: survey-reported and GPS-recorded. Their findings suggest that the two survey methods complement each other and should be used in tandem.…”

“…More specifically, we focused on the relation between these two approaches and on the ability to use them in a complementary manner in order to improve the evaluation of driving behavior. Recent literature suggests the potential strength of combining both technology-based and traditional approaches (see, for example, [4,30]). …”

Phantom trips: Overestimating the traffic impacts of new development

“…Studies comparing self-reported trips from NHTS-style surveys and GPS devices have found that between 10 percent and 35 percent 8 of GPS-identified trips go unreported in surveys (Bricka and Bhat 2006). Not all of the discrepancy is due to survey errors, as some GPS-based methods may be overly sensitive-for example, picking up the walk from an off-site parking lot to the destination as a separate trip or assuming that a long dwell at a traffic signal denotes a gap between two separate trips (Bricka et al 2012). Moreover, some of the underreporting concerns trips by nonmotorized modes, which are particularly difficult to capture in surveys but are not relevant to the analysis here.…”