Method for determining a reliability of a low-definition map in order to make the activation of at least one driving aid system of an autonomous vehicle reliable, said autonomous vehicle traveling on a road and comprising a navigation system and a perception system, the navigation system comprising said map and supplying mapped data, the perception system supplying measured data of the vehicle and/or of the external environment of the vehicle, said method being updated periodically when said vehicle is traveling on a road and comprising the steps of: • Reception of data mapped by the navigation system, the mapped data comprising at least one mapped slope of the road around the vehicle, at least one mapped curvature of the road around the vehicle, and a list of mapped road signs, called mapped list, the mapped list comprising, for each road sign, a type, a location and contextual information; • Reception of data measured by the perception system, the perception data comprising a measured slope of the road around the vehicle, a measured trajectory of the road around the vehicle, and a list of measured road signs, called the measured list, the measured list comprising, for each road sign, a type, a location and contextual information; • Determination of a route path, referred to as the mapped path, from the mapped curvature; • Calculation of a road correlation value from the least slope mapped, the mapped trajectory, the measured slope, the measured trajectory, the more the mapped data matches the measured data, the more the correlation value increases; • Calculation of a signal correlation value from the mapped road signs list and the measured road signs list, the more the mapped data matches the measured data, the more the correlation value increases; • Determination of a reliable or unreliable reliability indicator, the indicator being reliable if a combination of the route correlation value and the signaling correlation value is above a predetermined threshold. • Reception of data mapped by the navigation system, the mapped data comprising at least one mapped slope of the road around the vehicle, at least one mapped curvature of the road around the vehicle, and a list of mapped road signs, called mapped list, the mapped list comprising, for each road sign, a type, a location and contextual information; • Reception of data measured by the perception system, the perception data comprising a measured slope of the road around the vehicle, a measured trajectory of the road around the vehicle, and a list of measured road signs, called the measured list, the measured list comprising, for each road sign, a type, a location and contextual information; • Determination of a route path, referred to as the mapped path, from the mapped curvature; • Calculation of a road correlation value from the least slope mapped, the mapped trajectory, the measured slope, the measured trajectory, the more the mapped data matches the measured data, the more the correlation value increases; • Calculation of a signal correlation value from the mapped road signs list and the measured road signs list, the more the mapped data matches the measured data, the more the correlation value increases; • Determination of a reliable or unreliable reliability indicator, the indicator being reliable if a combination of the route correlation value and the signaling correlation value is above a predetermined threshold.