To avoid the mayhem that previously marred a downtown Halloween party that attracts up to 100,000 people, city leaders are imposing new restrictions and tighter controls this year.

Whether the changes are just the trick needed to make the Saturday night event a treat won't be clear until the witching hour, when the bars close and police want costumed revelers to leave. Officers have used pepper spray to disperse the crowd the past four years.

Playboy magazine cited the annual event when it named the University of Wisconsin-Madison the nation's top party school in April. But the celebration is taking on a different look this year, thanks to city and campus leaders who have tired of the violence.

Police had arrested 68 people as of early Saturday morning after the opening night of the celebration, significantly lower than the number of arrests following the party's start last year. Police spokesman Mike Hanson did not list the charges but said 13 of those arrested went to jail.

While the city has not officially sanctioned the event, it is for the first time selling tickets for access to State Street, a pedestrian-only avenue lined with bars, restaurants and shops. Police plan to block off streets to enforce the $5 admission fee.

City officials have lined up bands to play on two stages at either end of State Street. They gave the event a start and end time — 7:30 p.m. to 1:30 a.m. — and a name, "Freakfest on State Street."

Organizers hope to put a damper on the rowdy behavior by controlling access to the party. They also hope ticket sales will help to recoup some of the police costs, which were estimated at $600,000 last year.

"Our hope is that we can get through this year without having to use pepper spray or have cops in riot gear," Mayor Dave Cieslewicz said. "I'll consider it to be a success if the event ends peacefully, and there are no serious injuries and property damage."

But the city is making no promises. A Web site it created with details about the event carries a disclaimer: "The City of Madison cannot and does not guarantee your safety at this event. You enter the event area at your own risk and are responsible for your own actions and safety."

Based on ticket sales in the weeks heading up to "Freakfest," the changes were not going over well with people looking to party. Just 8,500 of the 80,000 tickets printed had sold as of Thursday.

Most tickets will be sold Saturday, in the hours leading up to the event, said Tom Wangard, a UW-Madison sophomore.

Wangard and other students initially argued for changing the location of the party to a nearby street to avoid the city's interference. But after working with city officials, Wangard now supports the event and said he expects it to be a success.

But he also said there is always a potential for mayhem.

In 2002, revelers threw rocks and bottles, breaking at least 12 windows and damaging police cars before officers broke out the tear gas.

In 2003, store windows were broken and at least two cars were tipped over. Then, in 2004, a small bonfire started. Police used pepper spray to break up the crowd and arrested 450 people.

Last year, 447 people were arrested. Police also used pepper spray to quell a crowd of about 2,000.

Police presence this year will be comparable to the past, with 225 officers on duty Friday night and more than 250 on duty Saturday, said Mike Hanson, a spokesman for Madison police.

Even though the bands will stop playing at 1:30 a.m., bars are allowed under state law to stay open until 2:30 a.m. And because daylight-saving time ends at 2 a.m., bar-goers will have an extra hour to imbibe.

The goal is to have State Street cleared and back to normal before the bars empty, said Joel Plant, the city's alcohol policy coordinator. In past years, revelers leaving bars added to the difficulty of dealing with the commotion started by others, he said.

"We're not going to force anything," Cieslewicz said. "As long as it's a peaceful, I don't care if I'm there until 5 in the morning."