How do self-driving cars perceive and react to their surroundings?

Self-driving cars use special sensors and smart cameras, like having superpowers to see everything around them.

Imagine you're playing hide-and-seek in a big park, you can see where your friends are hiding because you’re looking all around. Self-driving cars do something similar, but with many eyes: they have lidar, which is like a laser flashlight that bounces light off things and tells the car how far away they are; radar, which uses waves to tell the car about moving objects, like other cars; and cameras, which take pictures of everything, just like your eyes.

Once self-driving cars see what’s going on around them, they use computer brains to think fast. If a pedestrian suddenly runs into the street, it's like you seeing a friend pop out from behind a tree, the car quickly decides to stop or slow down.

They also talk to each other! Like when you and your friends pass notes in class, self-driving cars can send messages to nearby cars using wireless signals, so they know what’s coming next. That way, everyone stays safe and happy on the road.