Beyond GPS: Improved study of bicycling exposure through added use of video data.

Bicycling has become increasingly popular in the United States in recent years for both recreation and utilitarian purposes. Yet, attributes of the bicycle riding experience and riding differences between adults and children and males and females are not well documented. Most existing data on bicycling trip characteristics are based on self-reported interviews or surveys, which are prone to recall bias. The purpose of this exploratory study was to capture naturalistic bicycling data to examine trip characteristics and compare exposure classification accuracy between GPS and video data. We enrolled 10 children and 10 adults and captured their bicycling trips for one week each using PedalPortal, a GPS-enabled helmet camera data capture and coding system developed by the authors and a team of engineering students. Overall, 261 trips, 57 hours, and 670 miles of bicycling were captured. The video data allowed for correct classification of riding location (sidewalk, bicycle lane, street, etc.), an advantage over GPS data alone. Child trips were significantly shorter in both time and distance than adult trips (p<0.01). The majority of male trips were commutes (69.8% child, 60.5% adult), while female trips were more evenly distributed among commute, non-commute utilitarian, and recreation. Adults primarily chose paved streets with no bicycle facilities, but also sought out on-road bicycle facilities (bike lanes and shared lane markings). Children rode most frequently on sidewalks. Results from this study demonstrate that the addition of video data can improve classification of bicycling exposure and differences by age and gender that can help planners and engineers better understand bicyclist behavior variations and increase safety by selecting appropriate and targeted countermeasures.