They cannot "adapt". Your "retraining" is not a trivial process. Attempts to accommodate edge cases are not guaranteed to be able to cleanly accommodate all previous cases without discontinuities/regression/overfitting. The consequences of which could be especially catastrophic given that every other vehicle that safely operates may be relying on a particular quirk of a particular version of the neural network's particular function which it is imitating to safely operate in it's particular environment.

That's the problem with NN's. You can't say anything about them explicitly except that they meet the specification for their training datasets. Fitness for a task outside of that is not guaranteed. Humans, on the other hand, are constantly adapting, because they never stop "learning". This has the inverse effect in that you can say that a person can be trained for a task, but at the moment may not be.

When you apply an NN on an industrial scale, you can't just throw it out there without being willing to accept the liability for the destruction you cause as a result.