As of software version 2019.32.12.1 a small part of this issue has been addressed by Tesla. As of this version the TACC will no longer set speed to 150 km/h in an unrestriced zone. It will now default to 130 (or higher when going over 130 km/h).
While this at least reduces the number of scroll by 4, it still requires 10 frantic scroll to set speed to 80 km/h if needed. It will also still result in unexpected acceleration in speed restricted zone. This still isn't a solution to the problem.
There should be a clear intention from the driver to set TACC to the speed limit.
I still feel like this implementation would be most intuitive and safe:
- Stalk down and release = set to current speed
- Stalk down and hold = set to speed limit +/- offset (or current speed if above)
There is also a 'bump' on the stalk down movement when fully depressed down. That could also be used to set to max speed, but I feel like Tesla is reserving that interaction for something else. As far as I can tell the bump doesn't do anything at the moment, so that might also be a great way to set TACC to the speed limit with intention.
As long as there is a clear input by the user that the max speed should be set instead of current speed, the design should be much safer and more intuitive than it is now.
While this at least reduces the number of scroll by 4, it still requires 10 frantic scroll to set speed to 80 km/h if needed. It will also still result in unexpected acceleration in speed restricted zone. This still isn't a solution to the problem.
There should be a clear intention from the driver to set TACC to the speed limit.
I still feel like this implementation would be most intuitive and safe:
- Stalk down and release = set to current speed
- Stalk down and hold = set to speed limit +/- offset (or current speed if above)
There is also a 'bump' on the stalk down movement when fully depressed down. That could also be used to set to max speed, but I feel like Tesla is reserving that interaction for something else. As far as I can tell the bump doesn't do anything at the moment, so that might also be a great way to set TACC to the speed limit with intention.
As long as there is a clear input by the user that the max speed should be set instead of current speed, the design should be much safer and more intuitive than it is now.