Following high-profile incidents involving autonomous vehicle technologies, a report from AAA‘s multi-year tracking study indicates that consumer trust in these vehicles has quickly eroded.

Today, 73 percent of American drivers report they would be too afraid to ride in a fully self-driving vehicle, up from 63 percent in late 2017. Additionally, 63 percent of U.S. adults report they would actually feel less safe sharing the road with a self-driving vehicle while walking or riding a bicycle.

AAA’s latest survey found that Millennials-so far the group that has been the quickest to embrace automated vehicle technology-were the most impacted by these incidents. The percentage of Millennial drivers too afraid to ride in a fully self-driving vehicle has jumped from 49 percent to 64 percent since late 2017, representing the largest increase of any generation surveyed.

“While autonomous vehicles are being tested, there’s always a chance that they will fail or encounter a situation that challenges even the most advanced system,” said Megan Foster, AAA’s director of federal affairs. “To ease fears, there must be safeguards in place to protect vehicle occupants and the motorists, bicyclists, and pedestrians with whom they share the road.”