While mechanical gear selectors are always polystable, there are both polystable and monostable solutions for shift by wire technology. Polystable gears stay in the position selected by the driver. Monostable springs back to an former position.
Tests at Luleå University of Technology have shown that monostable shift by wire requires more cognition from the driver. In an initial field study, Sanna Lohilahti Bladfält asked subjects drive different cars with shift by wire on a roadway.
Risk of accidents
It turned out that many of the subjects had difficulty finding such fundamental functions as how to start and choose the direction of travel. It can have fatal consequences. There are examples of accidents where drivers have got stuck under the railway barrier and driven forward instead of backwards due to the gear being put in the wrong position.
– Most test persons perform better when they are allowed to use polystable gear selectors. In the old joystick model, you can feel with your hand how the gear unit jacks in the right position. You get direct feedback. The brain receives both visual and tactile information. With monostable shift by wire gears, you have to look at a display to check what position the gear is in, says the dissertation's author, Sanna Lohilahti Bladfält.
Must learn new things
Sanna Lohilahti Bladfält believes that in the future it may become more common to rent a car instead of owning it. If different car models have different gear solutions, the person who chooses to rent must learn the functions again for each rental car.
– It would be easier and thus safer if there was a common standard. It should be difficult to make mistakes. My hope is that the dissertation will be able to contribute to the development of an ISO standard that is adapted to the new shift-by-wire gear selectors.
But why are there so many different gear selectors despite the fact that road safety issues are well known in the industry? To get an answer to that, Sanna Lohilahti Bladfält conducted a number of in-depth interviews with people who work with the human-technology interaction in the automotive industry. The interviews showed that decision-makers often lack sufficient information to be able to make certain decisions. Knowledge and information can be obtained through usability studies, but the issue is in some cases a low priority and then there are no resources for such studies.
When resources such as time and money are scarce, the importance of social networks, both within and outside one's own organization, is extra important. It also makes it easier for different work groups to understand each other's needs in the work processes.
- It is a matter of time and money, but also language confusion. Those who work with human technology interaction simply find it difficult to get their views heard. An industry-wide standard would probably be a support for them.