Self-driving cars have countless obstacles to contend with on the road, chiefly drivers who don't always act predictably -- or responsibly. There's inclement precipitation and wind to worry about, plus jaywalking pedestrians and zippy electric bikes and scooters. That's not to mention alleyways and busy intersections that no amount of Google Maps data can elucidate. Perhaps it's not surprising, then, that Ghost Locomotion, a stealthy startup headed by former Yahoo CTO and Pure Storage cofounder John Hayes, isn't tackling a full stack autonomous car platform just yet. Instead, it's honing in on the task that constitutes two-thirds of all miles driven in the U.S.: highway driving.