Some authorities estimate we might have 10 million driverless vehicles roaming the world’s roads within the next two years.

Now, the Gallup people are out with a new survey titled  “Americans hit the brakes on self-driving cars,” suggesting that more than half of them on American roads may be riderless too.

The new mail poll of 3,297 adults by Gallup and Northeastern University finds that a clear majority of Americans (54 percent) say they are unlikely to ever ride in a driverless vehicle. Half of men say that, and 58 percent of women agree.

Fifty-nine percent overall say they’d have a high level of daily discomfort riding in one of those things (53 percent of men, 64 percent of women). Less than 23 percent say they’d be sort of or extremely comfortable riding in an unmanned death trap (28 percent men, 19 percent women), the survey reports.

Of course, given the economics, that’s not going to halt the global movement toward AI and automation, especially for driverless trucks. Where does a 100,000-pound driverless truck go? Anywhere it wants.

Nearly two-out-of-three Americans say they would be rather or extremely uncomfortable sharing the road with driverless trucks.

Even that notorious younger population cohort of Americans, many of whom shouldn’t be on the road in anything, are hesitant about driverless cars; half of the 18 to 35 set feel uncomfortable, while two-thirds (67 percent) of those 66 and over would be.

By education, Americans with a college degree, who are supposed to be smarter, are the most likely to be comfortable about robot cars (33%), while 45 percent show that their higher education was not worthless.

Driverless cars, however, do have some serious issues as yet unresolved legally. In an accident, who’s responsible for the driverless vehicle? What about miscreants hacking into driverless cars and taking unwilling passengers for a spin?

Or terrorists? What’s to stop them from programming a driverless vehicle to plow into and through a crowd of innocent pedestrians with or without a bomb inside?

In other unrelated survey news, 100 percent of this post’s writers expressed so much concern about driverless cars that he’ll stick with his rusting compact.