Assessing the utility of wearable cameras in the measurement of walking and cycling

Thesis

Walking and cycling are considered very important behaviours in public health. This thesis is a study of the measurement of walking, cycling and overall travel behaviour.

In the first part I present a systematic review of studies comparing Global Positioning System (GPS) measured travel to self-report. I found 12 results from eight eligible studies. All studies showed self-reported journey times were greater than GPS measured times. The differences ranged from over-reporting of +2.2 to +13.5 minutes per journey.

In the second part of this thesis, I describe the development of a feasible, valid and reliable method for measuring travel with automated wearable cameras (SenseCam) through field testing and two pilot studies. I compared my new method to direct observation (considered a criterion measure) and found very good agreement and reliability (inter-rater, intra-rater and inter-measure). I also present an ethical framework for the measurement of health-related behaviours using automated wearable cameras.

In the third part of the thesis, I report findings from an experiment designed to assess a well known UK travel diary (The National Travel Survey). Across four locations (Oxford, UK; Romford, UK; San Diego, USA; and Auckland, New Zealand) I collected 3-4 days of SenseCam and travel diary data from n=84 participants (convenience sample). Compliance with the collection protocol was high and inspection of the crude results suggests relative agreement between measures. Analysis of matched pairs of measurements (n=1,127 journeys) suggests a significant positive bias on self-reported durations (2:08 minutes; 95% CI = 1:48 to 2:28; 95% limits-of-agreement = -9:10 to 13:26).

These results suggest self-reported journey exposure is valid at a population level, though corrections according to my reported bias could be considered. The large limits of agreement on duration estimates suggest self-report may be unsuitable for assessment of individual travel behaviour.

Authors: Kelly, P

• Publication date: 2013
• DOI: 10.5287/ora-gwqjkzp41
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: Oxford University, UK
• Language: English
• Keywords: self-report; measurement; active travel; travel; wearable cameras
• Subjects: Public Health