how do you define safety programmatically so the vehicle knows what's considered 'safe'? Measurement of g-force in sudden deceleration, acceleration, lateral m

how do you define safety programmatically so the vehicle knows what's considered 'safe'? Measurement of g-force in sudden deceleration, acceleration, lateral movement? Heart beat per minute of passengers? Most passenger cars are far more capable than average drivers can exploit, so there is quite a bit of room for cars to drive very aggressively from human's perspective, but completely 'safe' from machine's perspective.