One day after Uber suspended its autonomous-drive test programs on public roads following a fatal accident in Arizona, Toyota Motor suspended tests of driverless cars on public streets in the U.S.

"Because we feel the incident may have an emotional effect on our test drivers, we have decided to temporarily pause our Chauffeur mode testing on public roads," said Brian Lyons of Toyota Motor North America.



As the National Transportation Safety Board investigates why a 49-year-old woman was hit and killed by an Uber test vehicle while in autonomous mode, the accident is raising questions about the safety of self-driving vehicles.

For all the talk about self-driving cars being on the cusp of giving passengers rides every day, there's one fact few want to discuss: Autonomous-drive cars get confused and don't always work.

"We know the last stretch here gets really hard," said Scott Corwin, managing director and future of mobility leader for Deloitte.

Tricky scenarios such as a construction site or a blocked driveway can befuddle sensors and computers in self-driving cars. As a result, the self-driving cars slow to a crawl or stop until a safety driver re-engages and takes control of the car to steer it through the situation.

But what happens when autonomous-drive cars have no safety driver? What are passengers supposed to do?