1. A method for alertness control of a vehicle operator, the method comprising: obtaining, by an apparatus, physiological status data of a person acquired using at least one sensor comprising at least a biosignal sensor; determining, based on at least the physiological status data, at least one alertness value being indicative of alertness level of the person; determining, by comparing the at least one alertness value to at least one alertness reference value, whether the alertness level of the person is below a threshold alertness level for operating the vehicle; and as a response to the determining that the alertness level is below the threshold alertness level, causing an output of a control signal.