Self-driving car companies are expanding their testing locations to cities with narrow, bumpy roads, bad weather, and culturally-specific driving conventions. Using a combination of radar, lidar, laser scanners, and cameras, self-driving vehicles are gearing up to work in the worst conditions possible. But while lidar (light detection and ranging) technology offers far more detail than radar does, it’s doesn’t hold up well under precipitous conditions. “If a laser beam hits a drop of water on the outside of the scanner, the lidar can think it’s an object right in front of the vehicle and slam on the brakes,” says Raj Rajkumar. But with more training and more testing, self-driving vehicles will be in the consumer market in no time. Read more.