Towards physically active populations: How do decision-makers justify 30km/h speed limits? A policy documents analysis

Background: Lowering speed limits from 50 to 30km/h are key in promoting physical activity. Still, implementing 30km/h limits remains challenging.

Purpose: We examine how local decision-makers justify and implement 30 km/h policies, and whether physical activity benefits were considered. We also studied urban-rural and neighbourhood socio-economic status(SES) differences herein.

Methods: Two researchers independently searched traffic decision documents from the Official Gazette of the Kingdom of the Netherlands to obtain all speed limit implementations in Amsterdam and Rotterdam and four rural municipalities between 2016-2022. One researcher extracted data using a customized form, including justifications and additional physical measures, which was checked by the second researcher. Traffic documents were integrated in a geographic database. Descriptive statistics about road length, justifications and implementation aspects were provided for the whole sample and separately for urban and rural areas and (in planned analysis) neighbourhood SES.

Results: We identified 47 documents covering 40km road length. Common justifications for 30km/h were traffic safety (N=20), vulnerable cyclists or pedestrians (N=8), livability (N=6), changes in local mobility (N=5), and child/school environments (N=5). No documents described physical activity benefits as justification for 30km/h. A minority of implementations included additional physical measures, mainly speed bumps (N=9) and/or pedestrian crossings (N=6). Larger shares of road length changed into 30km/h in rural (0.6%) than urban (0.4%) areas. In rural municipalities, pragmatic reasons such as lower nearby speed limits were often mentioned as compared to safety concerns and livability in urban municipalities.

Conclusions: Traffic safety is proposed as main benefit of 30km/h, while wider physical activity impacts are rarely put forward, even though car-light environments are known to be conductive towards physical activity.
Practical implications: Research should further highlight physical activity impacts of 30km/h. Considering these impacts can increase acceptance among the general population and policy-makers for 30km/h limits.

Funding: Vital Cities and Citizens.