When we let computers take over, who gets to control the computers?

http://www.theguardian.com/technology/2015/dec/23/the-problem-with-self-driving-cars-who-controls-the-code

"A car is a high-speed, heavy object with the power to kill its users and the people around it. A compromise in the software that allowed an attacker to take over the brakes, accelerator and steering (such as last summer’s exploit against Chrysler’s Jeeps, which triggered a 1.4m vehicle recall) is a nightmare scenario. The only thing worse would be such an exploit against a car designed to have no user-override – designed, in fact, to treat any attempt from the vehicle’s user to redirect its programming as a selfish attempt to avoid the Trolley Problem’s cold equations.
Whatever problems we will have with self-driving cars, they will be worsened by designing them to treat their passengers as adversaries.
That has profound implications beyond the hypothetical silliness of the Trolley Problem. The world of networked equipment is already governed by a patchwork of 'lawful interception' rules requiring them to have some sort of back door to allow the police to monitor them. These have been the source of grave problems in computer security, such as the 2011 attack by the Chinese government on the Gmail accounts of suspected dissident activists was executed by exploiting lawful interception; so was the NSA’s wiretapping of the Greek government during the 2004 Olympic bidding process."

I drive a lot for work. I've thought of scenarios where the poor computer program would be oblivious to the moral choices it faces in some situations. It would only know things like "avoid hitting something" and "if in doubt, slow down."  It might not know the human cost that such choices might require.  So, who gets to write that code then?  And who gets to decide?