Method for detecting the loss of vigilance of a vehicle driver

The invention relates to a method (1) for detecting a loss of vigilance of a vehicle driver when said vehicle is in the driving phase on a road. The main characteristic of a method according to the invention is that it comprises the following steps, • a step of determining (3) the state of the road, • a step of detection (4) of the loss of vigilance of the driver if the condition of the road determined in the previous step is considered good.