A method for controlling vehicle systems in a vehicle includes providing a steering wheel having a plurality of sensors configured to sense contact on the steering wheel. The steering wheel has a left zone and a right zone. The method includes determining a left contact value based on one or more signals received from at least one of the plurality of sensors. The left contact value indicates contact with the steering wheel within the left zone. The method includes determining a right contact value based on the one or more signals received from the at least one of the plurality of sensors. The right contact value indicates contact with the steering wheel within the right zone. The method includes determining a driver state index based on the left contact value and the right contact value and modifying control of the vehicle systems based on the driver state index.