While individual car use is a dominant mode of transportation in France, particularly in rural and low-density areas, it is important to promote the development of new sustainable travel paths in order to reduce dependence on cars. Planning policies and tools play a crucial role in defining such paths by providing decision-makers with a framework for data analysis, which can ensure efficient, safe, and sustainable mobility.The 2019 French mobility orientation law changed the rules of governance for mobility (i.e., management of transportation systems and mobility patterns). The territorial collectivities now have the choice of becoming mobility-organizing authorities. This law also introduced "simplified mobility plans" which aim to plan sustainable mobility on territories with less than 100,000 inhabitants. These planning documents are not mandatory but are crucial to build a policy aligned with mobility challenges, and consist of several steps, the first of which is conducting a mobility diagnosis.This thesis focuses on rural areas and on investigating the mobility diagnosis part which is a mandatory step of the simplified mobility plans, and which allows to provide a comprehensive understanding of transportation systems and mobility patterns and enable the identification of challenges and opportunities. Guided by theories on sustainable transitions and urban mobility planning, it details how to use and adapt existing tools to the specific context rural areas, that are constrained in both financial and human resources and are under-studied by current scientific research.Moreover, current methods for mobility diagnostics are too cumbersome and not always suitable for rural areas with limited resources. To address this issue, the thesis proposes a turnkey toolbox with relevant, easy-to-use indicators to standardize results and make regional - or national - planning easier.This master thesis tries in particular to answer the needs of mobility coordination by regions, in territories where local authorities have taken over mobility competences and where regions wish to support them in their planning efforts, especially in the implementation of their simplified mobility plans. A case study of Normandy will be used to understand the objectives at the regional scale when developing such simplified mobility plans.The results were obtained through a combination of qualitative methods, including document analysis as well as multicriteria analysis.The final output of the thesis is a new toolbox relying on the proposed methodology and indicators. It will simplify the process of conducting mobility diagnosis and therefore the understanding of mobility patterns in rural areas, which is key in developing plans to address their needs and to offer solutions for more sustainable and less car-dependent mobility.