Self-driving cars are scaring more Americans than they used to.

More people now say they would not ride in a fully autonomous car than those surveyed in late 2017, according to AAA.

Some 73 percent of U.S. drivers surveyed by AAA said they would be afraid to ride in a self-driving vehicle, a 10 percent jump from 63 percent in October.

About 64 percent of so-called millennials, ages 20-37, said they wouldn't ride — a big jump over the 49 percent at the end of 2017.

The report attributed the increased concern to highly publicized accidents involving cars operating autonomously. For example, a self-driving car operated by Uber killed a pedestrian in Arizona in March.

"I think this survey is telling us that if there is an incident with a self-driving car, it is going to get a lot of attention from the media and the public and likely there will be some impact on the consumer perception of its safety," said Greg Brannon director of Automotive Engineering for AAA.

Human drivers cause fatal accidents all the time, he added, but the novelty of autonomous driving technology subjects it to greater scrutiny.

The large increase in the number of millennials concerned about self-driving cars was also striking, Brannon said.

"Just as they are often the first to jump onto a new technology, maybe they are also the first to jump away from it," Brannon said.

AAA surveyed just over 1,000 people from April 5-8.