Judge William C. Harrison approved the city's request for a permanent civil injunction after a brief trial that began last week in Solano County Superior Court.
The temporary injunction, approved by the court in July 2009, resulted from a lawsuit filed against the Norteno gang by the city of Fairfield, its police department and the Solano County District Attorney's Office.
Police Lt. Darrin Moody said the permanent injunction applies to all gang members mentioned in the civil complaint and future gang members.
Two men named as gang members in the lawsuit, Lucio Gonzalez and Mario Huezo, challenged the injunction, claiming they are not Nortenos.
Harrison ruled Tuesday that the men are, indeed, members of the Norteno gang and therefore subject to the restrictions outlined in the injunction, Moody said.
The men's attorney, Paul Feuerwerker, did not return calls for comment.
The injunction prohibits Norteno gang members from associating with each other; being around open containers of alcohol or those who posses them; and possessing illegal drugs, paraphernalia, weapons, ammunition or graffiti tools or being around those who possess them.
The injunction also imposes a curfew from 10 p.m. to 5 a.m. in the safety zone, Moody said.
The safety zone is bordered by Interstate Highway 80 on the west, Cement Hill Road on the north, state Highway 12 in the south and Sunset Avenue and the Union Pacific railroad tracks in the east.
Moody said the judge also ordered an "opt-out" procedure that allows those who walk away from the gang and do not associate with it for three years to be exempted from the injunction.
Gang members who resume gang activity after opting out may be re-served with the complaint and the restrictions against them will be reinstated, Moody said.
The injunction process started when the city of Fairfield, the Fairfield Police Department and the Solano County District Attorney's Office filed a lawsuit against the Norteno gang on June 1, 2009, claiming it was a public nuisance.