The slide above shows the various methods of investigating the interiors.
The first picture (top left), shows an adjustable buck, which is nothing but a mock-up of the dimensions of the vehicle. The entire vehicle structure can be adjusted in numerous ways. This way the dimensions of a vehicle under development can be reproduced and subjective investigations of the vehicle interiors can hence be undertaken.
The second picture (top right), shows an ageing suit which designers use to simulate an aged driver. The suit limits the movement of the driver and hence changes the biomechanical forces that have to be applied during driving or in the seated position, hence giving the designer a better understanding of the comfort levels experienced by an aged person in the driver's seat.
The last picture (below), illustrates the use of a pregnancy suit which a designer uses to simulate the experience of a pregnant woman driving the vehicle.