Perceptions of road traffic conditions along with their reported impacts on walking are associated with wellbeing

•New empirical framework for associations between busy roads, walking, and wellbeing.•Perceptions about traffic volumes and speeds are formed jointly.•Perceptions depend on HGV traffic and current vs. historical and reference speeds.•Impact on walking associated with perceiving both traffic volumes and speed as high.•People with worst perceptions on traffic and impact on walking have lower wellbeing.