System and method for improving a performance estimation of an operator of a vehicle

System (400) for improving a performance estimation of an operator (202) of a vehicle (100), comprising a first module (402, 402', 402") implementing a first method (408) for estimating a performance state of vehicle operation, a second module (404) implementing a second method (410) for estimating at least one of a physiological and behavioural state of the operator (202), means for sharing an estimated state between one of the first (402, 402', 402") and the second (404) module and the other one of the first (402, 402', 402") and the second (404) module, wherein the implemented estimation method of one of the first (402, 402', 402") and the second (404) module is adjusted based on the state of the other one of the first (402, 402', 402") and the second (404) module, thereby improving the estimation of at least one of the performance state of vehicle operation and the physiological and/or behavioural state of the operator (202).