Most Americans are concerned that self-driving cars might be hacked to cause crashes, disable the vehicle in some way or even be used as weapons by terrorists, according to researchers at the University of Michigan.

What’s more, many people are at least a little worried that autonomous vehicles could be hacked to gain access to personal data. But most Americans have these same cybersecurity concerns about conventional vehicles, according to Michael Sivak and Brandon Schoettle of the U-M Transportation Research Institute.

Using an online survey of more than 500 Americans, the researchers asked respondents how concerned they are about hackers gaining access to personally owned self-driving and conventional vehicles.

The researchers found that 76% to 88% of people are at least slightly concerned that self-driving vehicles could be hacked to cause crashes, or to disable many vehicles simultaneously or disable the vehicles’ main traffic-management systems. More than 40% reported they are very or extremely concerned.

A total of 33% of survey respondents indicated they are extremely concerned that self-driving vehicles could be hacked to cause crashes.

About a third of respondents also indicated they are at least somewhat concerned that hackers of conventional vehicles could cause crashes, disable vehicles or use them for acts of terror, or to gain access to personal data.

“Hacking of vehicles is even a concern for conventional vehicles,” Sivak said. “But hacking of self-driving vehicles with controls is of greater concern, and hacking of self-driving vehicles without controls is an even greater concern.”

The researchers also found that women and older people are more likely to have strong concerns about cybersecurity than others.