Drive.ai claims its deep-learning technology is well suited to operating in challenging environments.
Drive.ai has released a video showing its autonomous prototype driving at night in the rain.
All major automakers are almost certainly testing in such conditions, but few have released videos showing how the technology operates when the sun goes down or road markings are obscured by glare during a downpour.
The Drive.ai demo reel appears to show a test cruise around Mountain View during one of California's recent rainy days.
"These are conditions drivers encounter every single day," the startup says. "Any successful self-driving technology will need to address countless unpredictable situations and a wide range of driving conditions, yet few are able to today."
A blog post accompanying the video points out a heavy downpour at 0:10, busy four-way stop at 1:00, broken red traffic light at 1:50 and confusing reflections on the wet ground at 2:35.
Rain is still a seemingly simple task compared to snow, which can cover all road markings, completely obscure signs, coat camera lenses and cause other problems that are difficult for both humans and machines to overcome.