BMW pairs Digital Key with a breathalyzer to curb drunk driving

BMW is taking a tech-first swing at the drunk-driving problem by leaning on the rise of smartphone-based digital keys. A recent patent filing lays out a system that pairs the Digital Key app with a breathalyzer—either built into the car or as a portable unit. The breathalyzer would send its reading to the app, and the app would permit the car to start only if the result stays below the legal blood alcohol limit.

What sets it apart from traditional ignition interlocks that hardwire into the car is the fully digital integration. On paper, that should make rollout smoother: less intrusion into the vehicle’s wiring and far more flexibility in how access rules and usage scenarios are set up. It sounds like the kind of approach that could fit more naturally into modern ownership habits.

The patent also outlines a middle-ground mode: even if driving is blocked, the system could still allow accessory power. In practice, that would let a person wait for a taxi in a warm cabin with ventilation and media running, without taking the car onto the road. It’s a considerate touch that addresses real-world behavior instead of pretending it doesn’t exist.

The most obvious use case is court-mandated driving restrictions. At the same time, the concept depends on a specific owner having—and activating—the Digital Key feature, so it’s not a one-size-fits-all solution for the entire vehicle fleet. As ideas go, though, it’s a pragmatic blend of safety, convenience, and modern car tech.