The primary project addressed by the NOMAD (The Nordic Open Mobility and Digitalization) project is the need for seamless, cross-border journeys involving scheduled services and on-demand services like taxis, micro-mobility, and car-pooling. 

The challenge lies in compensating for services provided by different Maas agents, whether publicly or privately funded. 

The project proposes a solution by standardizing interfaces between mobility providers, enabling the roaming of travel services and creating unified, user-friendly experiences. The Maas roaming concept, inspired by mobile phone roaming, envisions using local Maas agent apps to plan, book and pay for trips across borders. 

In Summmary, the NOMAD project addresses the complex landscape of corss-border mobility challenges, striving to create a standardized, user-centric approach to Maas roaming.