Designed primarily to navigate through on-screen menus in vehicles, automotive supplier Continental has developed a touchpad with haptic feedback. Similar to a mechanical button, the touchpad returns a palpable impulse if the driver selects a menu point. The company had the haptic feedback touchpad tested by researchers from the Kassel university as an independent institution. The results show that the approach indeed has a positive influence on the driver's behaviour. "Whenever the haptic function was activated, the test person showed 23% less glance diversion from the traffic. Plus, usage tasks were achieved on average 33% faster than with haptic feature deactivated", said professor Ludger Schmidt who oversees the HMI systems at the university's mechanical engineering department.
These results have been investigated in a driving simulator. The 32 test persons were instructed to perform lane-changing manoeuvres according to ISO 26022. At the same time, they had to select and activate functions from an on-screen menu. Such secondary tasks at the wheel can significantly reduce driving safety - the longer the driver looks to the screen instead of the traffic events around him, the longer the vehicle effectively drives along in 'blind flight' mode. During the tests, the touchpad has been placed within the driver's handling area beneath his right hand while the screen was located in the centre console. The separation of screen and HMI logic does away with an otherwise necessary coordination of hand and eye when operating a touch screen with the stretched finger. Instead, the driver's finger can slide over the touchpad without looking at its surface. Menu items on the screen are visually highlighted when the finger reaches them, much like a cursor on a computer screen. For each menu point touched with the finger, the touchpad generates a palpable mechanical pulse. If the driver pushes the touchpad with a certain force while a menu field is selected, the device acknowledges the function with another haptic pulse.