A Gang Injunction is basically a restraining-order banning any known gang members from doing any gang related activity. And that goes for everything from tagging to dance offs. While the constitutionality of injunctions is still up in the air (different cases have had different measures of success), it is said to be a success.
To get around rulings that called in question the legality of them, Herrera named twenty-two known members of the Oakdale Mob and gave a certain area in which they could not do anything. Everyone seems to think the thing is working and members named have not been involved in any illegal activities since the injunction. Or, at least, none that anyone has discovered.
A similar measure thing has been going on in Sacramento, with differing results.