A method and a device are disclosed for determining data representative of the layout of a road in a two-dimensional Cartesian coordinate system, the coordinate system being associated with a vehicle travelling along the road. To this end, a first set of first points in the Cartesian coordinate system is determined on the basis of data representative of at least one image of the road environment in front of the vehicle. A second set of second points is determined in the Cartesian coordinate system on the basis of mapping data of the road environment of the vehicle. The data representative of the road layout are obtained on the basis of a part of the first points and a part of the second points.