One example of a comprehensive, national implementation of such a platform-enabled on-demand marketplace is FlexDanmark (see Box 1). This system builds on regulatory requirements to ensure health- and education-related accessibility across the country to create a nationally co-ordinated and optimised on-demand transport facilitated by a common IT platform. By centralising information on demand and creating a marketplace to provide flexible supply, it enables specialised trips (medical, school, etc.) For example, some operate fixed routes that are in-part crowd-sourced by users (e.g. Chariot - see Figure 2) and others offer services where riders are directed to pop-up stops within defined geographic areas.