Method for measuring a distance, comprising the following steps: - transmitting at least a first optical transmission signal with a predefinable first signal form by means of a transmitter via a first transmission path whose transmission function depends on the physical variable to be measured, in particular the distance, wherein a first optical reception signal (s1') is obtained at an output of the first transmission path, - transmitting at least a first reference signal (sr) with a predefinable reference signal form over a reference transmission path, which has a known transmission function, and wherein a reference reception signal (sr') is obtained at an output of the reference transmission path, - analyzing the first reception signal (s1') and the reference reception signal (sr') in order to infer the distance as physical variable, wherein, in the context of the analysis, the distance of the transmitter of the first transmission signal from an object is inferred, wherein, for determining one of the distances, the analysis comprises the following steps: - adding the reception signal (s1') to the reference reception signal (sr') by means of an adding unit in order to obtain a sum signal, - evaluating predefinable time periods of the sum signal in order to infer a phase shift of the transmission signal caused by the first transmission path, - inferring the distance from the phase shift, wherein the first reference signal (sr) is an optical signal and the reference transmission path is configured as an optical transmission path and wherein the adding unit is realized by a single photodiode, which at the same time transforms the optical reception signals (s1', sr') into respective electrical signals, characterized in that, in the context of the analysis, the distance (d1, d2) of one or several areas (701, 702), in particular of a bodywork, of a vehicle from a road surface and the distance from another object, in particular another vehicle, is determined, wherein the distances (d1, d2, d3) to the road surface and to the other object are determined alternately, and wherein the determination of the distances is based on the sending of transmission signals from the one transmitter, and wherein the transmission path used for distance measurement is realigned. - transmitting at least a first optical transmission signal with a predefinable first signal form by means of a transmitter via a first transmission path whose transmission function depends on the physical variable to be measured, in particular the distance, wherein a first optical reception signal (s1') is obtained at an output of the first transmission path, - transmitting at least a first reference signal (sr) with a predefinable reference signal form over a reference transmission path, which has a known transmission function, and wherein a reference reception signal (sr') is obtained at an output of the reference transmission path, - analyzing the first reception signal (s1') and the reference reception signal (sr') in order to infer the distance as physical variable, wherein, in the context of the analysis, the distance of the transmitter of the first transmission signal from an object is inferred, - adding the reception signal (s1') to the reference reception signal (sr') by means of an adding unit in order to obtain a sum signal, - evaluating predefinable time periods of the sum signal in order to infer a phase shift of the transmission signal caused by the first transmission path, - inferring the distance from the phase shift, wherein the first reference signal (sr) is an optical signal and the reference transmission path is configured as an optical transmission path and wherein the adding unit is realized by a single photodiode, which at the same time transforms the optical reception signals (s1', sr') into respective electrical signals,