Fig. 2From: Pre-hospital and retrieval medicine in Scotland: a retrospective cohort study of the workload and outcomes of the emergency medical retrieval service in the first decade of national coverageIsochrone maps of time to critical care unit in Scotland in two transport models. The first, modelled time by road alone to each critical care unit (Fig. 2a) and the second, modelled time using the faster of either road or the current configuration of aeromedical services to each critical care unit (Fig. 2b)Back to article page