A new survey of people in the U.S. and Germany found that 55% of respondents wouldn’t consider riding in a fully autonomous vehicle, but 71% might consider riding in a vehicle that’s partially autonomous.

Survey participants primarily cited concerns about technology failures and security to explain their reluctance to trust self-driving cars. Technology research firm Gartner conducted the online survey, which polled 1,519 Americans and Germans from April through May of this year.

Though multiple launches of autonomous vehicles are expected around 2020, the full impact of autonomous vehicle technology on society and the economy will not begin to emerge until about 2025, Gartner projected in its report of the survey results. Consumer and social acceptance will be crucial to widespread adoption.

“Fear of autonomous vehicles getting confused by unexpected situations, safety concerns around equipment and system failures, and vehicle and system security are top concerns around using fully autonomous vehicles,” said Mike Ramsey, research director at Gartner.

Survey respondents acknowledged, however, that fully autonomous vehicles offer many advantages, including improved fuel economy and a reduction in the number and severity of crashes. Additional benefits they identified included having a safe transportation option when drivers are tired and using travel time for entertainment and work, Gartner reported.

The survey found that consumers who currently embrace on-demand car services are more likely to ride in and purchase partially and fully autonomous vehicles.

“This signifies that these more evolved users of transportation methods are more open toward the concept of autonomous cars,” Ramsey said.

The percentage of people who used a mobility service, such as Uber or Car2Go, in the past 12 months rose to 23% — up from 19% in a similar survey conducted two years earlier. But the transition to dropping a personally owned vehicle will be challenging outside of dense urban areas, Gartner found.

Among surveyed automobile owners who have a driveway or other easily accessed parking, nearly half of them said they would not consider giving up their own vehicle — even if they saved 75% over the cost of owning their own car. The ability to leave at any moment was the most cited reason for not replacing personal vehicles with on-demand car services. Trust and personal safety are also top concerns.

“The automotive industry is investing in new safety and convenience technology at a rate not seen since the dawn of the automobile,” Ramsey said. “The experience of owning and operating a car will be dramatically different in 10 years.”

Dozens of companies are currently developing sensors and other technologies required to enable vehicles to detect and understand their surroundings. As of mid-2017, more than 46 companies are building artificial intelligence (AI)-based software to control an autonomous vehicle and make it operate in the world, according to Gartner.

“Autonomous driving technology will fundamentally transform the automotive industry, changing the way vehicles are built, operated, sold, used and serviced,” Ramsey said.