Waymo expands to 15 US cities but edge cases keep stumping its driverless cars

Waymo is rapidly scaling its driverless car service across 15 U.S. cities, but the expansion is exposing a growing number of so-called edge cases — unexpected situations the vehicles have no pre-programmed script to handle. The more cities and miles Waymo covers, the more novel scenarios its autonomous systems encounter, requiring continual algorithmic updates to keep pace.