Let's start with auto-braking systems.
On the surface, this sounds fine. Cars that take over the braking if the driver doesn't react fast enough is much like ABS brakes of the 90s. People didn't like the idea of the brakes not being in the driver's control, but ABS has prevented lots of cars and trucks from losing control and is now an accepted technology.
But as similar as these sound, auto-braking is not just a fancier and better Anti-Lock brake system.
Auto-braking can be hacked, and it will not require a pimply teenager to do it (although they will be among the first to discover the hacks)
Today, if you cut someone off and slam on the brakes in front of them, the driver in the rear has the option of ramming into you for your bad behavior. In a future with auto-braking cars, the computer will take that option away from you.
So, if the auto-braking car is being followed too closely by a human driven car behind it, and some pimply kid with a learners permit cuts off the auto-braking car and slams on the brakes in front of it, the computer will react and prevent the front end collision – While reacting faster than the human behind it could possibly react, THUS causing a rear-end collision to occur.
I also foresee other hacks.
When cars use optics and radar to 'see', both can be hacked. Painting illusions and such on roads could trick auto-driving cars into changing lanes when no human would. And radar can be jammed. This will become the high-tech equivalent of tossing rocks from overpasses.
It will happen.