Definition
Plain language
The person sitting in a test vehicle ready to brake or take over at any moment.
As stated in the literature
Human supervisor with authority over an experimental autonomy stack; disengagements are the termination condition for failed runs.
Also called: safety drivers
Why it matters: Their takeovers are both the safety net that makes on-road testing possible and the clearest measure of how often the system actually failed.
For example, during a test run the person in the driver's seat grabs the wheel when the car drifts toward the cones, ending that attempt.
Heard on the show
“An attentive safety driver sat with a foot over the brake, and all ten failed attempts ended with that person braking.”Episode 284 — Four AI Models Steered a Real Corolla, and Only One Finished