A lot of people may still have serious reservations about riding in fully autonomous vehicles, a new survey from Gartner indicates.

The Gartner Consumer Trends in Automotive people surveyed about 1,500 people in the United States and Germany from April through May, and found that 55 percent of the people they spoke to would not ride in a fully autonomous car.

However, just over 70 percent would ride in a car that was partially autonomous. Gartner defined partially autonomous vehicles as those that could drive autonomously, but allow a driver to retake control of the car if needed.

Advocates of autonomous driving have said the technology will actually make driving safer, since statistics indicate human behavior is the major cause of most auto crashes.

But many consumers familiar with the tendency of other electronic devices to sometimes malfunction or perform erratically still seem to have trouble accepting the idea of being held in a vehicle that could fail.

"The big issue is that people are afraid of being in vehicles where they cannot exercise some control," said Gartner research director Mike Ramsey, in an interview with CNBC.