The modern car has a problem. Over the past decade, automakers have raced to offer their smartphone-addled customers a bonanza of features: navigation, texting, phone calls, satellite radio, Bluetooth, ways to check tire pressure and oil temperature, suspension settings, charging status, and more. Then they try to stick all those things into an interface whose users are usually pretty busy—driving the 2-ton metal boxes that kill nearly 40,000 people in the US every year.