Reddit Video Shows AMD GPU Running Open-Source Driver Assistance in Toyota as NHTSA Probes comma.ai

In the video, the Alphard's dashboard holds the AMD card, with wiring running down the center console. The setup delivers 21.4 TFLOPS of single-precision floating-point computing power, a 100-fold increase in FLOPs, and 288 GB/s of memory bandwidth, according to ifanr. It runs a local end-to-end model called Chestnut with 880 million parameters, a scale the report compares with Tesla's HW4 platform. The system is not entirely a homemade project; it comes from comma.ai, and a palm-sized device fixed to the windshield can, in theory, give an older car similar capabilities for $999.

comma.ai was founded by George Hotz, known in hacking circles as Geohot. Hotz unlocked the original iPhone's network lock at 17 and later broke into the PlayStation 3, prompting Sony to take legal action. In 2015, he turned to cars, modified a two-year-old Acura into a prototype with driver-assistance functions, and rejected an invitation from Elon Musk to join Tesla, according to the report. He founded comma.ai and launched the comma One for $999. Before delivery, the National Highway Traffic Safety Administration demanded technical details and threatened fines of up to $21,000 per day. Hotz canceled the launch and published the code on GitHub as openpilot. The hardware was repositioned as a developer kit, and the software became compatible with more than 100 vehicle models.

Installation requires no replacement of original parts. A user removes trim near the interior rearview mirror, connects the comma harness in series, and runs a power line to the OBD port. The device intercepts the original camera feed and sends commands through the CAN bus to steering, brake, and throttle controllers. An infrared camera monitors the driver's eyes; if the driver looks down at a phone or falls asleep, the device sounds a loud alarm, and if there is no response, it slows down and disengages steering control.

Legal treatment differs by country. In the United States, aftermarket driver-assistance devices occupy a gray area with no explicit prohibition, leaving risk to the driver. In China, changing steering and braking systems is illegal modification; the report says such changes fail annual inspections, void the original vehicle warranty, and lead insurers to deny payouts after crashes.

Last month, NHTSA opened an investigation into comma.ai's aftermarket driver-assistance devices, covering the comma three, 3X, and comma four hardware and the openpilot software, involving about 30,000 vehicles. Public materials record five severe highway collisions with three deaths and 11 injuries. The crashes generally occurred when openpilot failed to avoid stationary or slow-moving vehicles in the same lane. In Missouri, a Honda Accord rear-ended a vehicle at 82 mph after the driver activated openpilot and fell asleep. In Louisiana, a Toyota RAV4 hit a roadside rescue vehicle without slowing, according to the report.

The investigation highlights both driver complacency and technical limits. Open source gives users freedom to modify software, and driver monitoring can be bypassed. Control authority also varies by model: in some cars, openpilot can only control steering while acceleration and braking rely on the factory cruise system. If a driver dozes off, the system can only issue alerts and disengage steering assistance. Modified software means two cars with the same device may run different algorithms, complicating responsibility after a crash.

Windshield-mounted devices have long faced power and heat constraints, typically using ordinary automotive chips and running models with only 29 million parameters. To address summer heat throttling, the comma four removed its large interactive screen and used the internal space for cooling. To break the computing bottleneck, comma.ai and its community developed an external graphics card solution. Through an expansion port, owners can connect desktop GPUs such as the RX 9060, or even use a Mac mini as a vehicle host, producing the Reddit spectacle.

The approach remains niche. Across three hardware generations, comma.ai has shipped just over 30,000 units. In March 2025, the comma 3X passed 10,000 sales, a single-model record for the company. As Tesla lowers the threshold for FSD and automakers equip new cars with better pre-installed driver assistance, the need to buy external hardware and modify wiring narrows the space for aftermarket systems.

Hotz stepped down as CEO and left management at the end of 2022. He said he was good at zero-to-one technical breakthroughs in a garage, not at managing supply chains, compliance reviews, and production, according to ifanr. He founded a new company and developed the lightweight deep-learning framework tinygrad, aiming to challenge Nvidia in AI infrastructure. comma.ai is now run by a professional management team, and its San Diego factory still assembles devices and flashes firmware, but the company faces a crossroads as regulation and pre-installed driver assistance close in.