Outdoor lighting and active travel: A high-resolution analysis using satellite imagery and Strava data in Glasgow

Introduction:

The benefits of active travel are well-established. While previous research has explored how built environment factors (such as population density, accessibility, land use, and infrastructure) influence active travel, micro-scale features like outdoor lighting have received less attention. This study examines associations between outdoor lighting levels and active travel in Glasgow, accounting for broader contextual factors and distinguishing between daylight and dark conditions.

Methods:

We used Strava data, satellite-derived outdoor lighting imagery, and other spatial datasets aggregated to small-area zones in Glasgow. Bayesian spatial models (Besag–York–Mollié) were fitted to estimate associations between contextual variables and distances travelled on foot, by bike, and by both modes combined, separately for daylight and dark hours.

Results:

Outdoor lighting levels derived from night-time satellite imagery were positively associated with walking, cycling, and overall active-travel distances during both light conditions (daylight and dark). These associations were stronger during dark hours, particularly for cycling. Several contextual relationships also varied by light condition: industrial density was positively associated with cycling only during daylight, while quietness and gradient showed stronger associations during daylight. Population and income deprivation were negatively associated across all modes under both light conditions.

Conclusions:

Our findings underscore the potential relevance of lighting in shaping active travel patterns after dark, particularly for cycling. They also highlight the need for future research that considers light conditions and time of day in environmental studies of mobility, as well as across broader contexts, specific locations, and diverse population groups – to better inform equitable and effective active travel policy.