The disclosure describes systems and methods that pertain to interactions between a vehicle and an occupant within the vehicle. Each teat cup has a centrally located longitudinal axis extending through a first end surface of the teat cups provided with a recess for receiving a teat of a milking animal and a oppositely located second end surface of the teat cups and wherein the teat cup handling device includes at least two holding parts arranged to releasably hold the teat cups. The detector may be mounted on existing equipment or may be used to monitor a tubing at any position along the tubing, and may operate in a stand alone mode or in combination with existing equipment.