Ramps are closed from Highway 100 to I-94. Construction workers will lay steel for a new railroad bridge and construct storm sewers at the Highway 100 interchange. Credit: Rick Wood

By of the

Thousands of people in southeastern Wisconsin can bond over one thing this weekend: potentially massive driving delays.

A closure of I-94 westbound and eastbound, between Highway 100 and U.S. 45, begins at 11 p.m. Friday and runs through 5:30 a.m. Monday.

That means anyone hoping to get from Waukesha County to downtown Milwaukee or from downtown to Madison or from Illinois to northern Wisconsin can expect backups.

So here's a word to the wise: Plan as much as possible for this freeway free-for-all.

Here's everything you need to know for coping with the closure.

1 Why is this happening?

The closure was planned months ago to make major headway on the $1.7 billion reconstruction of the Zoo Interchange, which is Wisconsin's busiest, carrying more than 300,000 cars a day, according to the state Department of Transportation. (It's also one of the oldest, dating back to the 1960s, hence the need for new infrastructure.)

Over the weekend, crews will lay steel for a new railroad bridge over I-94 and install storm sewers near the freeway.

2 Why this weekend?

Mike Pyritz, regional communication manager for the DOT, said this weekend's work would have dragged on for months, and caused even more delays, if it weren't consolidated into such a short time.

"We wouldn't schedule this if we didn't think we could do (the work) in just 54 hours," Pyritz said.

Meanwhile, he acknowledged that any weekend would cause a headache for Wisconsin riders.

But this weekend was chosen, he said, because it didn't coincide with any of the summer's biggest events. Summerfest is finished, the State Fair is days away and the Brewers are in Washington, D.C.

Don't hold your breath for a rescheduling: Pyritz said that would happen only in severe weather, and this weekend is supposed to be bright and sunny. Perfect gridlock weather!

3 How bad will these delays be?

Pyritz estimated that about 90,000 drivers will be delayed over the weekend. He noted that this is not only the biggest planned closure of the summer, but also the largest in the first two years of the Zoo Interchange Project. (But be warned now: The project is to continue into 2018.)

Pyritz said drivers should expect to add at least five to 10 minutes to any trips near the freeway.

Even so, he said, "there's no reason to not go out and enjoy any events."

That should be a relief to anyone planning to feast at Festa Italiana, the annual Italian heritage festival, which runs Friday through Sunday.

Festa's organizers said the closure won't have any effect on the festival, and released a brochure on alternate routes for visitors.

It should also be noted that northbound and southbound traffic on I-894/U.S. 45 will remain open the whole weekend.

4. What about other places near the freeway?

The delays inspired a brochure blast by organizations that are close to the closed-down road: The Milwaukee Regional Medical Center and the Milwaukee County Zoo also released information on alternate routes, and have no planned service changes.

Fear not for the Wisconsin State Fair, either: Pyritz said the construction will be done before the July 31 opening day.

The DOT also released its own suggestions for alternate routes along city streets, some of which might require a motorist Magellan to navigate. Check out the Journal Sentinel's guide to bypassing the backed-up area.

5. When will the traffic be worst?

Probably on Saturday, between 10 a.m. and 6 p.m.

"That's when we usually see the most delays and the highest traffic counts on any weekend," Pyritz said. "So that's when we're expecting the worst this time."

6. What are local law enforcements doing to help?

Officers from about 10 local law enforcements will be on hand to help the whole weekend, including the State Patrol and sheriff's deputies from Milwaukee and Waukesha counties, according to Capt. Timothy Carnahan of the State Patrol in Waukesha.

"There will be many people there to facilitate traffic and respond to any accidents," he said.

Carnahan also advised that, when drivers are nearing the area, they should turn down their iPods and instead tune into local radio stations for any updates on traffic flow.

Another bit of advice from Carnahan: "If you can at all avoid the area, please do."

7 How can I stay informed?

Check with jsonline.com and download our travel app for live updates. We also want to hear from you throughout the weekend with news, questions or complaints. Use the hashtag #I94zoo to give a dispatch on the delays.

Twitter: @jaysunsilver