openpilot: Open-Source Driver Assistance for Cars
/openpilot
openpilot is comma.ai's open-source project for upgrading the factory ADAS on supported cars, replacing the automaker's stock decisions with its own perception, planning, and control code. The license text calls the software alpha-quality and built for research, not a finished product. Reach for openpilot if you want to run or modify a real driver-assistance stack on a comma four; skip it if you need something certified and turnkey.
An Open-Source Robotics OS for Cars
openpilot is comma.ai's robotics operating system, currently applied to upgrade driver-assistance behavior in more than 300 supported vehicles. It runs on comma's comma four hardware, wired into the car through a car harness, replacing the vehicle's stock ADAS decisions with openpilot's own perception, planning, and control stack. The project ships under the MIT license, with some components carrying other licenses.
Key Capabilities and Development
- โOnce installed on a comma four wired in through a car harness, openpilot runs as the ADAS layer on any of the 300+ cars listed in the project's compatibility docs.
- โPrebuilt branches cover different stability levels: release-mici/release-chestnut/release-tizi for the stable release, matching -staging branches for early access, and nightly plus nightly-dev for bleeding-edge builds.
- โThe safety-critical layer that enforces limits on the vehicle lives in a separate project called panda, written in C, distinct from the Python-heavy openpilot codebase.
- โEvery commit triggers software-in-the-loop tests, and comma separately runs a hardware-in-the-loop Jenkins suite plus a testing lab where 10 comma devices continuously replay recorded driving routes.
- โDevelopment follows ISO26262 guidelines documented in SAFETY.md, and panda carries its own independent hardware-in-the-loop safety tests on top of openpilot's.
- โA one-line quick-start command, bash <(curl -fsSL openpilot.comma.ai), pulls the release build; deeper setup and code docs live at docs.comma.ai and in a community wiki.
- โcomma pays bounties to outside contributors and lists open engineering roles, so development isn't limited to comma's internal team.
Setting Up openpilot
Getting openpilot onto a car takes four pieces: a comma four device (sold at comma.ai/shop/comma-four), a car harness that wires it into the vehicle, one of the 300+ supported cars, and the software itself, installed by entering the URL openpilot.comma.ai during the comma four's own setup flow to pull the release build. For development work off a car, the quick-start is one command: bash <(curl -fsSL openpilot.comma.ai). Step-by-step harness and device installation instructions live at comma.ai/setup, and the docs note openpilot can run on other hardware too, though that path isn't plug-and-play. You can also run master or any other branch directly, but comma recommends sticking to one of the prebuilt release, staging, or nightly branches instead.
Who Should Consider openpilot?
openpilot fits developers and comma-four owners who want a real, inspectable driver-assistance stack running on one of the 300+ supported cars, or who want to contribute code through comma's Discord, its written contributing docs, or its paid bounty program. It's the wrong pick if you want a certified, liability-free safety product: the license text calls the software alpha-quality and built for research, not a finished product, and puts the burden of local legal compliance on you.
Strengths
- โThe entire driver-assistance stack, including the safety-critical panda firmware, is open source under MIT instead of sealed inside a factory ECU.
- โSafety testing is layered and documented in the repo: ISO26262 guidelines, per-commit software-in-the-loop tests, a hardware-in-the-loop Jenkins suite, and a testing lab of 10 devices replaying recorded routes.
- โThe installation hardware is a defined, purchasable kit (comma four plus car harness) instead of a wiring project you have to reverse-engineer yourself.
- โDevelopment activity is visible from outside comma: prebuilt nightly and staging branches, a public roadmap link, and paid bounties for external contributors.
- โOut of the box it covers 300+ cars, so many drivers won't need to write custom vehicle integration code just to get it running.
Important Considerations and Disclaimers
- โณThis is not a certified safety product. The license text bundled with the repo calls it alpha-stage software meant strictly for research, not a finished product, with no warranty of any kind.
- โณGetting it into a car means buying specific hardware first, a comma four plus a car harness, rather than just installing software; running on other hardware exists but isn't plug-and-play.
- โณopenpilot uploads driving data by default, including road-facing camera footage, CAN, GPS, IMU, magnetometer, and thermal sensor logs, to comma's servers for model training, among other telemetry; opting out is possible but not automatic.
- โณThe license requires users to indemnify comma.ai against claims tied to their use of the software, a real legal obligation worth reading before wiring it into a car.
- โณLocal legal compliance is explicitly the user's own responsibility per the license text, not something openpilot handles for you.
Alternatives to openpilot
Frequently Asked Questions
openpilot currently works with more than 300 supported cars, according to the compatibility list in docs/CARS.md in the repository. Check that list before buying hardware, since not every car and trim level is covered.
Running openpilot in a car takes a comma four device, a car harness to connect it to the vehicle's wiring, and one of the 300+ supported cars. The docs also note it can run on other hardware, but that setup is not plug-and-play.
openpilot follows ISO26262 guidelines and runs software-in-the-loop tests on every commit, with the safety-critical code isolated in panda and tested separately on real hardware. That said, the license text itself calls this alpha-stage research software, not a finished product, with no warranty expressed or implied.
By default, openpilot collects user data: it uploads driving information such as road-facing camera footage, CAN, GPS, IMU, magnetometer, and thermal sensor logs to comma's servers, which comma uses to train its models. Users can disable data collection, and the driver-facing camera and microphone are logged only when you opt in.
openpilot is released under the MIT license, though the docs note some parts of the software carry other licenses as specified in the codebase.
The MIT license itself permits commercial use, but openpilot's own license text separately calls the software alpha-stage, meant for research, and not a finished product, which is worth weighing against any commercial deployment plans.
The problem it solves
Factory driver-assistance systems ship as closed firmware: you can't see what the perception or planning code is doing, and you can't change it if you disagree with a decision it makes on the road. openpilot frames its own reason for existing around that gap, presenting itself as a buildable, inspectable robotics operating system rather than a sealed black box wired into the dashboard.
Best use cases
- โขUpgrading ADAS behavior on one of the 300+ supported cars using comma's own comma four hardware and a car harness.
- โขStudying or modifying real driver-assistance perception and control code, since the full stack is open source under MIT.
- โขContributing to the safety-critical panda firmware or the wider openpilot codebase via comma's bounty program, Discord, or contributing docs.
- โขTesting upcoming features early by running the nightly or staging branches ahead of the stable release.
- โขAuditing how a driver-assistance stack handles safety testing, since SAFETY.md and the software-in-the-loop suite are both part of the public repo.
Related repositories
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