The ONISR (French national inter-ministerial observatory on road safety) needs to annually measure changes in the use of active modes of transport in order to compare them with accident statistics. The aim of the project is therefore to set up an Active Modes Mobility Observatory (OBSMMA). This observatory will comprise indicators which are aggregated nationally, updated annually, and which reflect the overall mobility of the following modes of transport: walking, cycling and personal travel equipment. As no annual national source of data on active mobility exists, we decided to calculate these indicators by extrapolating data from surveys undertaken by third parties: the mobility of persons survey (EMP), the population census and the EMC².