A method for wrong-way driver detection, including a step of reading in position data via an interface, the position data representing a measured position of a vehicle, a step of reading in map data mapping road segments negotiable by the vehicle, a step of reading in a plurality of particles, one particle representing an assumed position of the vehicle and a weighting assigned to the assumed position, and a step of determining a deviation between the plurality of particles and the measured position represented by the position data, using the map data.