UPDATED 06/11/12 9:00 p.m.

CHICAGO (CBS) — Teachers in the Chicago Public Schools have voted overwhelmingly to authorize a strike, and are prepared to hit the picket lines if they need to.

As CBS 2’s Derrick Blakley reports, parents are already concerned about what the vote could mean this fall.

LISTEN: WBBM Newsradio’s Regine Schlesinger reports

At a news conference on Monday afternoon, union officials said nearly 90 percent of teachers voted in favor of a strike authorization.

“We have the pulse of our members, and we listened to what they had to say,” CTU President Karen Lewis told reporters.

Union leaders insist the vote does not mean they will necessarily walk out. But they say it does show that teachers mean business.

“The vote has well surpassed the 75 percent threshold required by state law, with some school networks voting 100 percent to authorize a strike” teachers union spokeswoman Stephanie Gadlin said in a statement. “While the union has made no determination on whether a strike will be needed, leaders say the authorization vote has now given them added leverage at the bargaining table.

Chicago Public Schools CEO J.C. Brizard downplayed speculation the strike-authorization vote will influence the way his side negotiates.

“We’ve been very, very serious. I don’t know how much more serious we can be,” he told CBS 2’s Dana Kozlov.

Brizard said school officials will do “everything possible” to avoid a strike.

But some parents Monday morning were anxious about what the vote means for their school and their children. The academic year is winding down, but parents are concerned that school might not start on time next year.

“I think it lowers the hurdle,” said Steve Gohres, the parent of a child at the South Loop School, 1212 S, Plymouth Ct. “If you’re all set and primed, it’s just one less process that you have to go through to implement it.”

“I’m very concerned about it,” added Sharon Kurth, a South Loop School grandparent. “I hope that they can find a way to make this work for the sake of the children, and for the teachers.”

Chicago Public Schools chief executive officer Jean-Claude Brizard issued a statement on the vote Monday morning.

“The Chicago Teachers Union leadership pushed their members to authorize a strike before giving them the opportunity to consider the independent fact-finder’s compromise report due in July. That’s a shame. The CTU leadership left the teachers with a choice between a strike and nothing — that’s a false choice,” Brizard said in the statement. “As a former teacher, I am disappointed that union leadership would rush their members to vote for a strike before having the complete information on the table.”

Brizard has said previously that the vote was rushed by the union. He said the authorization vote would have been more appropriate if it had been held in the last week of August. That way, Brizard says, retiring teachers wouldn’t have voted on a deal that he says won’t actually affect them.

But CTU president Karen Lewis believes the huge mandate will give her increased clout at the bargaining table, where the two sides are far apart on wages. She is asking for a 29 percent raise over two years, while the city is offering just 2 percent.

Lewis has also said the fact-finding report only addresses a few of the many issues in the teachers’ contract.

Most South Loop parents agree the teachers deserve a pay hike, particularly since all of them will be dealing with a longer school day next school year.

“I think the commitment is greater, and they need to be compensated for it,” said South Loop parent Donya Peterson.

But parents say that compensation should not come at the cost of kids losing class time.

“They should be doing whatever they can to make sure our children are taking full advantage of all the time they have in the school year,” said South Loop parent Michelle Calvin.

The CEO of the Illinois Policy Institute, a conservative think tank, says the union is disconnected from reality.

“Chicago teachers on average, make $71,000,” John Tillman tells CBS 2’s Mike Parker. “The average taxpayer in the city of Chicago, makes about $48,000.”

As for the union complaints that teachers are being overloaded with work, Tillman says: “Everybody’s being asked to do more. Private workers all over the country and the state are being asked to do more, because times are tough.”

Under the process laid out in state law, teachers could not strike until mid-August at the earliest.

If teachers called for a strike, it would have to be ratified by another vote by the union’s house of delegates.