ATLANTA — As heavy rain fell on Wednesday afternoon and many of Atlanta’s roads flooded, one woman got stuck inside her driverless Waymo.
Rachel Knudsen says the Waymo figured it out and moved on, but happened again a few minutes later.
“The Waymo didn’t appear to be slowing down as much as I would have expected it to slow down and hit the water,” she told Channel 2’s Richard Elliot over the phone. “It wasn’t, you know, an incredibly deep pool of water, but it was enough.”
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She said that Waymo eventually credited her ride and sent a human driver to get her home.
Elliot spoke with an expert to figure out why the car stopped in the middle of the floodwaters.
Waymo says it uses three types of sensors to drive its cars, one of which uses lasers. Heavy rain can scatter the light from those lasers.
Georgia Tech’s Dr. Glen Chou, an avid Waymo user, says the water can act as a prism to scatter the light and momentarily confuse the Waymo.
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But, like humans, Dr. Chou says that Waymos can struggle to determine just how deep a puddle is.
“In general, these are not equipped on cars, and so they will typically struggle to get precise estimates of puddle depth, which can cause issues like we’ve seen,” he said.
He says that, regardless, he trusts Waymo and is confident that these are small problems that the company is working on.
For now, Waymo has pulled its cars off the Atlanta streets to look at these issues.
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