A method for determining the plausibility of wrong-way travel of a motor vehicle when entering a directional roadway, including detecting at least one curve information item of a current travel path, ascertaining at least one curve information item of a permitted travel path, determining a deviation between the detected and ascertained curve information items, and plausibilizing a wrong-way travel if a deviation exists or a deviation limit value is breached. A control/detection device for determining the plausibility of wrong-way travel when entering a directional roadway, includes an arrangement for detecting at least one curve information item of a current travel path; an arrangement for ascertaining at least one curve information item of a permitted travel path; an arrangement for determining a deviation between detected and ascertained curve information items; and an arrangement for determining the plausibility of wrong-way travel if a deviation exists or a deviation limit value is breached.