The reality is that the outcome matters, the "harm" matters, in criminal trials. Not just intent. I go into a store to rob it and someone dies in the course of that robbery, I may be guilty of felony murder. Even if I didn't directly cause the death, don't have a gun, and didn't ever intend for anyone to get hurt. We have a crime of attempted murder that is different from murder. Our laws recognize that two identical acts may deserve different punishments based on the harm that directly results from those acts.
So maybe all she did was recklessly drive, or "fail to maintain a lane". If a cop was following a driver, saw them swerve into the shoulder and pulled the driver over (probably to check for intoxication), if the driver was sober that ticket might be all they get, if that. But the same actions, if it results in death, may deserve a different charge and punishment. That's how the law works, there's nothing odd about it.