Rotation path detection device

A rotary travel detection device for public transport vehicles comprising:

• a drive device for a pivotably and/or slidably mounted entry/exit facility, including a drive unit comprising:
• an electrical drive motor,
• a first reduction gear unit connected to an output shaft of the electrical drive motor via which torque for moving the entry/exit facility is transmitted,
• a second reduction gear unit also connected with the electrical drive motor and located between the electrical drive motor and,
• an encoder for determining a position of an output shaft of the second reduction gear unit via which no torque for moving the entry/exit facility is transmitted,
• wherein this drive unit is disposed in and drives a rotation post, which rotates about an axis of rotation in opening and closing processes, and opens and closes the entry/exit facility, and is retained, via a retaining component, on the vehicle, wherein the retaining component acts as a counter-bearing for a torque of the drive unit so that the output torque of the drive device can be transmitted onto the rotation post that rotates.