Some 43% of U.S. drivers said they would feel less safe if they had to share the road with a small, self-driving delivery vehicle, according to a new survey from AAA and the Technology and Public Purpose Project at Harvard Kennedy School’s Belfer Center for Science and International Affairs. 

Moreover, the survey findings indicate drivers get even more anxious when the self-driving vehicle is larger — with 53% saying they would feel less safe sharing the road with a self-driving semi-truck. 

Americans are still skeptical about safety and autonomous vehicles (AVs). The survey found most U.S. drivers have concerns, with the vehicle type and driving scenario making little to no difference in easing that apprehension.

For example, while 47% admitted they’d feel less safe driving along with self-driving vehicles on a highway or freeway, an almost equal number of respondents, 44%, said the same about self-driving vehicles on local or neighborhood streets.

The survey found implementing specific measures could ease driver anxiety. 

Some 62% said they would feel safe if self-driving vehicles were clearly marked. Moreover, safety confidence was boosted in 60% of respondents in the event self-driving vehicles stayed in designated lanes. Finally, 31% of those surveyed said they’d feel safe if self-driving vehicles were restricted to using the roads on specific days and times.