@article{ref1, title="Traffic exposure near the Los Angeles-Long Beach port complex: using GPS-enhanced tracking to assess the implications of unreported travel and locations", journal="Journal of transport geography", year="2011", author="Houston, Douglas and Ong, Paul and Jaimes, Guillermo and Winer, Arthur", volume="19", number="6", pages="1399-1409", abstract="Traffic exposure assessments could misclassify the extent and locations of exposure if traditional recall surveys and self-reported travel diaries do not record all participant activities. The Harbor Communities Time Location Study (HCTLS) examines the nature, extent and implications of underreported locations/trips in a case study which used portable Global Positioning Systems (GPS) devices to track the diurnal patterns and traffic exposure of 47 residents of communities near the Los Angeles-Long Beach port complex. Participants were similar to adults nationwide in time spent indoors, in-vehicle, and outdoors, but spent more time indoors at home (78% vs. 66%). Overall, participants did not report nearly half (49%) of the locations and trips identified in GPS-enhanced data on their activity diaries, resulting in about 3 h/day in unreported locations and 0.6 h/day in unreported trips. The probability of a location/trip being underreported was systematically correlated with participant and location/trip characteristics. Self-reported data missed about 50 min of heightened air pollution exposures during the 5 h/day on average participants spent in high-traffic areas and about 30 min during the 4 h/day near truck routes. GPS-enhanced methods provide opportunities to more precisely characterize exposure periods and tools to identify facility, roadway, and land use types of the greatest concern for mitigation efforts.

", language="", issn="0966-6923", doi="10.1016/j.jtrangeo.2011.07.018", url="http://dx.doi.org/10.1016/j.jtrangeo.2011.07.018" }