[the8472]

> we can be absolutely certain

Such a thing does not exist. You can only add more nines (e.g. heartbeats, check sensor jitter etc.). At some point you're more likely to be ran over by another car than the tesla slowly, patiently crushing you at 2km/h.

Of course that doesn't mean tesla is actually that reliable.

[dragonwriter]

Heartbeats won't catch UI freezes, which I've seen on phones. Hopefully, those would result in a drop of the input signal rather than it locked in its prior state, though.

[redfern314]

Heartbeat would hopefully also include a counter, so that a locked input signal would result in the vehicle rejecting the heartbeat (sees that each message is the same instead of incrementing the counter).

No guarantee that's how they implemented it, though.

[shawnz]

They could mitigate such a failure mode by requiring a constant motion, like swiping a knob back and forth continuously