Are cars vulnerable to hackers?

A new paper discussed in the NY Times argues that automobiles' computer systems will be vulnerable to hackers as the systems become more connected to the internet and networked. I'm all for taking control of the car away from drivers, but this sounds bad:

“We demonstrate the ability to adversarially control a wide range of automotive functions and completely ignore driver input — including disabling the brakes, selectively braking individual wheels on demand, stopping the engine, and so on,” they wrote in the report, “Experimental Security Analysis of a Modern Automobile.”