John Ayala, head of the group's local chapter, says Guardian Angels will now begin riding Metro's buses and trains four days a week.
"And the reason for this is to be a deterrent to the assaults that are going on in the subway system, the gang recruiting, and then hopefully also we are planning to recruit some of the young people age 15 and above," he says.
Ayala says Guardian Angels will be on hand to defuse any tense situations and if there is an attack, he says his members will intervene and detain people for police.
Ayala says Guardian Angels will patrol Friday and Saturday night and two days during the week when school gets out.
He says the group will concentrate on specific buses and rail lines.
Recent statistics show crime rates on Metro at their highest in five years.