General Motors is preparing to push software updates to more than four million vehicles across its American fleet — replacing a familiar voice assistant with Google’s Gemini. The rollout, announced this week, covers all 2022 and newer models sold under the Cadillac, Chevrolet, Buick and GMC nameplates that are equipped with Google Built-in technology and connected to GM’s OnStar telematics service. It arrives as an over-the-air software update — no dealership visit required — and is widely expected to redefine what drivers mean when they say their car is “smart.” “This is one of the largest in-vehicle A.I. deployments we’ve ever seen at this scale,” said one industry analyst who tracks connected-vehicle technology. “The question has always been whether automakers could move fast enough to meet the moment. GM just answered that.” From Commands to Conversations For years, in-car voice assistants have operated like particularly unforgiving bureaucrats: they responded to precise, pre-approved phrases and punished any deviation with a terse “I didn’t understand that.” Google’s Gemini, by contrast, is designed to behave more like a well-informed passenger — one fluent in logistics, local knowledge and, when the moment calls for it, small talk. Drivers in qualifying vehicles will be able to ask Gemini to summarize and translate incoming text messages, draft replies on their behalf and send them without lifting a finger from the wheel. They can request a playlist tuned to their mood or the length of their drive, plan a multi-stop route optimized for fuel cost or trailer-friendly parking, and identify restaurants, gas stations and attractions along the way — all without restarting the request from scratch if the first answer doesn’t quite hit the mark. The assistant also supports more discursive use cases: brainstorming ideas for a work presentation, organizing thoughts before a difficult phone call or