Waymo One received a few weeks ago the license to test autonomous cars in California without a safety driver. But with some restrictions, including that the cars can only drive during dry weather conditions and some light rain.
Rain is a challenge, because rain drops on cameras and LiDARs reduce the view and reflection on drops distract the light and reduce the signal intensity. The companies are working on algorithms to correct those signals.
Here is an example how the Tesla Autopilot – a driving assist system in the firmware-version 184.108.40.206 is influenced by rain and what objects the system recognizes. Here is footage from seven of the eight cameras:
Here ist the same drive from the perspective of the narrow camera:
Also Torc Robotics is testing its vehicles in rain Here is a compilation of drives during rain, unfortunately without much explanation. Even when the sun is shining, the reflections from a wet road can interfere with the proper recognition of lane markings, which the car typically tries to identify.
As can be seen from this footage, the cars can drive with some confidence during rain, but for a high level of safety, there needs to be more work done. But rain is not automatically shutting down the cars, as some experts often communicate.
This article was published in German.