That is not quite correct either. You cannot be 'convicted' of entering the bicycle lane because that is not a criminal offense. You can be charged with manslaughter and there you have to consider the culpability, or the state of mind of the defendant. I think we can disregard the possibility that the cop *intended* to kill the cyclist, so that leaves us with considering recklessness or negligence.
For *recklessness* you would need to prove that the subject knowingly broke the law disregarding the possible risks. This is typically the case where most of the cases of killing people with a car while breaking the law (drunk driving, speeding, etc.) fall in - if you do that and kill someone, you have been driving recklessly and will be prosecuted for vehicular manslaughter. It does not apply to the cop, because he drifted in the bicycle lane unknowingly.
*Negligence* applies to cases where you can argue that "a reasonable person with the same general knowledge and abilities" as the accused would have reacted in that situation differently thus avoiding the disaster. In general, cases where you broke the law unknowingly fall here as well as cases where people fail to exercise more caution - e.g. not slowing down in an extreme rain storm, snow, etc. There you could argue that a typical "reasonable person" would slow down, or that a "reasonable person" would recognize that he/she is breaking the law. In the TFA case you would have to prove that a typical cop either would not have texted while driving or that a typical cop would not have crossed the lane while texting. Both of those would be really hard to prove in a court of law.