In the studies described below we concentrate on simple static vibration signals.
This was feasible because our test situation required no extreme turns. Thus, there
was no risk of the wheel being turned around to a degree where a vibration on the left
side of the wheel might be felt at the driver’s right hand. Participants were instructed
to keep both hands on the wheel. To ensure that they felt the vibration regardless of
where their hands were located (the next motor might be a few centimeters away from
the hand) the vibration signal had to be put on maximum intensity. This unfortunately
resulted in some vibration transmitting to the entire wheel, negatively affecting the
ease of distinguishing left/right vibration.