Programmers have to make decisions about those things all the time. It isn't like the product team defines every nitty-gritty detail of implementation -- especially for machine learning and AI algorithms.
A lot of AI is based around training sets not traditional Algorithms like your thinking of. There are simply to many edge cases to deal with by hand. Yes, there is also a lot of hand coding in these systems, but good training sets are very critical.
The choice of those training sets, including their contents, their size, how they are consumed, and the algorithms they are fed to, affects the output. Therefore, programmers make decisions. It is unavoidable.
Even if they weren't, it is unrealistic to assume that programmers have no input into the decisions that go into building the training set, which in this case involves where, and in what conditions, the prototype cars are driven.
PS: I expect company's to punt with a user selectable: how much to speed buttons.