In the video below, Dr. Kathleen Fisher, a DARPA program manager, talks about the ability to hack into car computer systems. She explains how it is possible to remotely control modern cars through Bluetooth and smart phone technology.
DARPA, short for Defense Advanced Research Projects Agency, is the Department of Defense agency responsible for the development of new technologies for use by the military.
Her talk demonstrates that such an ability exists and the Pentagon has researched it.
Fisher makes the comments within the first three minutes of the following video.