The disclosure relates to a method for detecting the passing of a motor vehicle through a road sign gantry, having the steps: receiving information on the surroundings, detecting road signs in the information on the surroundings, selecting a first road sign and a second road sign which together form a road sign gantry, acquiring position data for the first road sign and for the second road sign from the information on the surroundings, determining a gantry width between the first road sign and the second road sign, determining a first distance of the motor vehicle from the first road sign, determining a second distance of the motor vehicle from the second road sign, and detecting the passing through of the vehicle as a function of the gantry width, the first distance and the second distance.