It’s mens rea, lit. “guilty mind”, e.g. intent. If you take an action with the intent to cause a death, that’s murder (in my state, that would specifically be malice murder). If you take an action that is likely to cause a death with reckless indifference, but not intent, that’s usually something like murder in the second degree. If you cause a death through negligence or by accident, that’s usually some form of manslaughter.

Most traffic accidents are negligent; people don’t (…usually…) get into a car with the intent to kill someone, nor are they usually driving in a way that the know is likely to cause harm to other people. There are obvs. factors that will affect this–such as driving drunk–but causing a death is usually unintentional, and not through reckless indifference.

Assuming that your backup isn’t also infected.

Doesn’t have to be in the bank either; if you’re traveling with your life savings in cash, then if you get pulled over cops are likely to seize that money. Just because fuck you, that’s why.