Keith Naughton:

Google, especially, has Reuss’s attention. Last year he declared it “a very serious competitive threat.” At other times, he’s been snappish: “We’re in the car business today, and they’re not,” he said over the summer. But on the GM test oval, as he rides in the Super Cruising Caddy, he’s talking peace, perhaps even alliance. “I’m not sure it’s an us-vs.-them thing,” he says. Whether or not that partnership comes to pass (they already work together on some smaller stuff), Reuss, 52 and a GM lifer, says it’s imperative that he …
 Suddenly a crescent-shaped light on the steering wheel goes from green to red and the Caddy starts drifting in its lane. Reuss grabs the wheel. A test car just whooshed by on the left, and another slowed down on the right—too much traffic for Super Cruise, making it shut down.
 “That’s stuff we need to just work on,” Cindy Bay, the project’s head engineer, says from the back seat.
 “Yep,” Reuss says, hitting a couple of buttons to restart Super Cruise. “We need to develop it.”