Due to legal regulations and the impending demographic aging of society, urban mobility service providers are increasingly confronted with the inclusive design of local public transport. Accessibility is a basic prerequisite for people with restricted mobility to be able to participate in society in a self-determined way. Quality standards are defined and reviewed in discussions and negotiations between transport companies, public transport authorities and stakeholders. These standards are the basis for the design of any infrastructure, vehicle fleet, information, and operation to promote accessibility. The aim of this paper is to determine how the review of the accessibility of public transport can be improved by means of mystery shopping using a prototypical app. The mobile application enables the cooperative evaluation of public transport services from the perspective of mobility-restricted users (e.g. those in wheelchairs) across the mobility chain. We subsume and extend relevant evaluation criteria and implement them in a mobile application to be used during field work while cooperating with the back office of a public transport company. The app is tested in both usability tests and a field test and in dialogue with the users; its correct functioning is confirmed.