2.A motor vehicle operator who knows he is involved in an accident and knowingly leaves the scene of that accident under circumstances that violate the provisions of R.S.39:4-129 shall be guilty of a crime of the third degree if the accident results in serious bodily injury to another person. The presumption of nonimprisonment set forth in N.J.S.2C:44-1 shall not apply to persons convicted under the provisions of this section.If the evidence so warrants, nothing in this section shall be deemed to preclude an indictment and conviction for aggravated assault or assault by auto under the provisions of N.J.S.2C:12-1.Notwithstanding the provisions of N.J.S.2C:1-8 or any other provisions of law, a conviction arising under this section shall not merge with a conviction for aggravated assault or assault by auto under the provisions of N.J.S.2C:12-1 and a separate sentence shall be imposed upon each conviction.Notwithstanding the provisions of N.J.S.2C:44-5 or any other provisions of law, whenever in the case of such multiple convictions the court imposes multiple sentences of imprisonment for more than one offense, those sentences shall run consecutively.For the purposes of this section, neither knowledge of the serious bodily injury nor knowledge of the violation are elements of the offense and it shall not be a defense that the driver of the motor vehicle was unaware of the serious bodily injury or provisions of R.S.39:4-129.