How Self-Driving Cars Work

Designed for Safety At Every Step

Waymo is building a driver—not a car. Waymo’s goal is to build technology that’s a safe, cautious, and defensive driver—and the most experienced driver on the road. Ultimately, Waymo’s technology will be a fully self-driving system, allowing people to stay passengers the entire trip. Waymo is designed to operate without a human driver, unlike technologies sold in cars today such as adaptive cruise-control or lane-keeping systems which require constant monitoring by the driver. Waymo can handle the entire dynamic driving task within a geographic area and under certain defined conditions.

Seeing and Understanding the World

Waymo’s Sensors

Waymo’s sensors allow it to see 360 degrees, both in daytime and at night, and up to nearly three football fields away. This multi-layered sensor suite works together seamlessly to paint a detailed 3D picture of the world, showing moving and still objects.

Waymo self-driving car sensors

LiDAR System

Waymo’s LiDAR (Light Detection and Ranging) system works day and night by beaming out millions of laser pulses per second—in 360 degrees—and measuring how long it takes to reflect off a surface and return to the vehicle.

Vision System

Waymo’s high-resolution camera system is designed to work well at long range, in daylight and low-light conditions. Because it detects color, it can help Waymo vehicles spot traffic lights, construction zones, school buses, and the flashing lights of emergency vehicles.

Radar System

Radar uses wavelengths to perceive objects and movement in front, behind, and on both sides of the vehicle. These wavelengths are able to travel around objects like rain drops, making radar effective in rain, fog, and snow, regardless of the time of day.

Supplemental Sensors

Waymo has additional sensors, including an audio detection system that helps the vehicles hear police and emergency vehicle sirens up to hundreds of feet away, and a GPS to supplement Waymo’s extensive understanding of its physical location in the world.