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Updated: Mar 20, 2026

Trajectory Data Analyses for Pedestrian Space-time Activity Study
Published on: February 25, 2013
Brief report: Using global positioning system (GPS) enabled cell phones to examine adolescent travel patterns and
Hilary F Byrnes1, Brenda A Miller1, Christopher N Morrison2
1Prevention Research Center, Pacific Institute for Research and Evaluation, 180 Grand Avenue, Suite 1200, Oakland, CA 94612, USA.
Abstract:
As adolescents gain freedom to explore new environments unsupervised, more time in proximity to alcohol outlets may increase risks for alcohol and marijuana use. This pilot study: 1) Describes variations in adolescents' proximity to outlets by time of day and day of the week, 2) Examines variations in outlet proximity by drinking and marijuana use status, and 3) Tests feasibility of obtaining real-time data to study adolescent proximity to outlets. U.S. adolescents (N = 18) aged 16-17 (50% female) carried GPS-enabled smartphones for one week with their locations tracked. The geographic areas where adolescents spend time, activity spaces, were created by connecting GPS points sequentially and adding spatial buffers around routes. Proximity to outlets was greater during after school and evening hours. Drinkers and marijuana users were in proximity to outlets 1½ to 2 times more than non-users. Findings provide information about where adolescents spend time and times of greatest risk, informing prevention efforts.
Related Concept Videos
Introduction to Global Positioning System
Field Application of Global Positioning System
Types of Global Positioning System Surveys
Design Example: Identifying the Locations of Monuments in the Field Using Global Positioning System Device
Errors in Global Positioning System
Selected Data About Geographic Locations

