Definition
Plain language
A small aftermarket computer that mounts on a car's windshield and can take over steering and speed.
As stated in the literature
Comma.ai dashcam-style device running openpilot; interfaces with the vehicle's existing steering and longitudinal control buses.
Also called: comma 4
Why it matters: It turns an ordinary car into a platform where outside software can actually steer, which is what makes real-road testing of driving systems possible without building a vehicle.
For example, a driver can clip the device to the windshield of a compatible car, plug it into the car's wiring, and have it hold the lane and manage speed on the highway.
Heard on the show
“The hardware was a 2022 Corolla with a comma four computer mounted on the windshield, running a modified version of openpilot driver-assistance software.”Episode 284 — Four AI Models Steered a Real Corolla, and Only One Finished