Pedestrian mobility and innovative data sources: a literature review focused on app-based GPS data

Pedestrian mobility remains one of the most challenging transport modes to observe and analyse. Recent studies have advanced the field by using Global Positioning System (GPS) data from smartphone applications, yet their contributions and limitations have not been systematically reviewed. This article examines 95 studies using app-based GPS data and groups them into three application types: fitness/activity trackers, application aggregators, and travel-survey apps. Each offers a distinct perspective on pedestrian behaviour shaped by what data are collected, and how they are generated, shared, and processed. Fitness apps yield extensive, fine-grained traces but mostly capture recreational walking and running. Aggregators provide wide coverage and continuous monitoring but offer limited behavioural detail. Travel-survey apps supply richer contextual and socio-demographic information but face sampling constraints. These differences shape the kinds of questions and analyses that can be addressed in pedestrian mobility research. The review shows that using different app-based data sources for pattern identification and contextual interpretation, with careful ethical and methodological attention, can strengthen diverse pedestrian planning applications, such as assessing pedestrian-oriented urban environments and examining spatial inequalities in walking opportunities.