1. Lidar: Lidar (Light Detection and Ranging) sensors use laser light to create high-resolution 3D maps of the environment. This data is used to detect objects, lanes, and other features on the road.
2. Radar: Radar sensors use radio waves to detect objects and measure their distance and speed.
3. Ultrasonic sensors: Ultrasonic sensors use high-frequency sound waves to detect objects and measure their distance.

This sensor data is processed in real-time by Waymo's autonomous driving system, which uses machine learning algorithms to interpret the data and make decisions about vehicle control.