We’ve already reported that BMW owners have more drunk driving citations per capita than any other brand. Last year, BMW drivers faced 3.09 citations per 1,000 drivers. Ram truck owners came in second with 3.00 per 1,000. It looks like BMW isn’t taking this “win” lightly. The automaker just patented a breathalyzer key.

Like nearly every other automaker, BMW allows you to download an app and store a digital “key” for your car on your phone. With your phone in your pocket, you only need to hit the engine start button, and you’re ready to race off — if you’re sober.

BMW filed a patent with the World Intellectual Property Office for an app variation that could prevent you from starting your car until you blow into a breathalyzer. The breathalyzer could be attached to your car, or it could be an accessory you connect to your phone. But there’s more.

How BMW’s patent could change interlock systems

The automaker also proposed a feature that allows an owner to power on the ignition to use the heat or even the infotainment system with an illegal BAC. This could keep someone from freezing after the bars close and before a sober friend arrives to drive them home.

The idea of a breathalyzer in your car is nothing new. Borg-Warner developed the technology in 1969. Today, many states have “voluntary ignition interlock” options. If you’re caught driving drunk one too many times and a judge threatens to take your license, they may allow you to install an interlock device on your own car and keep using it. This is always at the judge’s discretion. But it’s a way to keep someone on the road if they need their car to commute.

What would the BMW patent do then? It could make the cost of setting up your car with an interlock device much cheaper. You’d only need to purchase a good breathalyzer that can connect to your phone, ask BMW to permanently change your startup settings, and you’re good to go.