N.J. Stat. § 39:4-51
A person who has been convicted of a first or second violation of section 39:4-50 of this Title, and in pursuance thereof has been imprisoned in a county jail or workhouse in the county in which the offense was committed, shall not, after commitment, be released therefrom until the term of imprisonment imposed has been served. A person imprisoned in the county jail or workhouse may in the discretion of the court, be released on a work release program.
No warden or other officer having custody of the county jail or workhouse shall release therefrom a person so committed, unless the person has been released by the court on a work release program, until the sentence has been served. A person sentenced to an inpatient rehabilitation program may upon petition by the treating agency be released, by the court, to an outpatient rehabilitation program for the duration of the original sentence.
Nothing in this section shall be construed to interfere in any way with the operation of a writ of habeas corpus, a proceeding in lieu of the prerogative writs, or an appeal.
The chief administrator shall adopt such rules and regulations to effectuate the provisions of this section as he shall deem necessary.
N.J.S. § 39:4-51