The thought of cruising down the highway and passing a vehicle with no one behind the wheel makes many motorists nervous.

Almost 70% of people said they were afraid of self-driving vehicles, up from 55% last year, according to a new survey from AAA survey. Such findings mean automakers need to do a better job at making self-driving technology safer and more reliable, the auto club said Thursday. 

“We were not expecting such a dramatic decline in trust from previous years,” said Greg Brannon, AAA’s director of automotive research, said in a statement. “Although with the number of high-profile crashes that have occurred from over-reliance on current vehicle technologies, this isn’t entirely surprising.”

Most of those high-profile crashes involving self-driving vehicles come from Tesla. Last month, the Elon Musk-owned automaker recalled some 363,000 vehicles with self-driving technology because the cars sometimes ignore posted speed limits or blow past intersections. The National Highway Traffic Safety Administration (NHTSA) has launched investigations into 35 separate Tesla crashes, 19 of which were fatal, since 2016.

Two of those probes are centered on accidents in California and Ohio, where drivers said Tesla’s self-driving mode caused a crash. A Tesla was involved in a different crash in January when the car plunged 250 feet onto a rocky beach, but California Highway Patrol troopers said they don’t believe the self-driving feature was engaged before the accident. 

The problems facing Tesla’s self-driving mode drew attention last month when a little-known consumer advocacy group aired a Super Bowl ad to highlight the automakers problems with autonomous driving. 

Tesla, which has disbanded its media relations department, could not be reached for comment. The automaker discloses on its website that its cars cannot drive themselves and that owners must be ready to intervene at all times.

Concerns over self-driving vehicles comes as automakers race to build them. Waymo, the self-driving technology arm of Google parent Alphabet, has tested millions of vehicles on public roads while Volvo, Nissan, Audi and other automakers are also working on autonomous vehicles, according to University of Michigan data. 

Americans have an increasingly negative perception of self-driving cars in part because of confusion over what the tech can and cannot do today, AAA said. The auto industry uses phrases like Autopilot, Propilot or Pilot Assist when marketing the feature, but the terms are often misunderstood. The survey found that 1 in 10 respondents believed they can put a vehicle in self-driving mode and fall asleep, AAA said.