Mind-boggling I-88 traffic solution nears finish line

 
 
Posted9/12/2015 12:00 PM

It was innovative, maybe even mind-boggling. But when the "diverging diamond" reconfiguration of the I-88 and Route 59 interchange was proposed more than five years ago, it wasn't even the front-running idea.

"Some of the preliminary information we've reviewed on diverging diamond interchanges suggests they may be more appropriate at places with less volume," a state highway official told tax watchdog Jake Griffin, then our DuPage County reporter. The interchange near the Aurora/Naperville border handles about 50,000 cars daily, and its backups are notorious.

                                                                                                                                                                                                                       
 

And, as you read this, it's probably a really good idea to stay away for a bit.

On Friday night, six of the eight ramps of the interchange were closed. For 10 days, this means:

• No tollway traffic can exit onto Route 59.

• Drivers heading north on Route 59 can enter the tollway heading east.

• Drivers heading south on Route 59 can use the ramp to go west on I-88.

And that's it.

If all goes well, everyone will be using a diverging diamond by the end of the month. I've looked at maps, drawings of the new traffic pattern, and will readily admit it still makes my head spin. Basically, it routes traffic to the opposite side of the tollway overpass, which eliminates left-hand turns in front of oncoming traffic of the limited-access interchange. Think of it this way: You're eastbound on I-88 and you exit at the ramp for Route 59. If you wish to head south, simply stay in the right-hand lane and merge with southbound traffic. To go north, you take the same ramp, but stay in the left-hand lane, which bends into the northbound lanes that have been routed to the left-hand side of the overpass. You switch back to the right-hand side of the road at a stoplight controlling the switch-over on the other side of the overpass.

Simple, huh? Nothing can possibly go wrong. (For further understanding, I highly recommend the YouTube video, https://www.youtube.com/watch?v=oSWjDbWnRzQ, a computer animation showing how all this will work.)

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Actually, because of the elimination of left-hand turns, traffic experts predict fewer and less-serious accidents.

That would be welcome relief, seeing that several intersections along Route 59 perennially make Naperville's list of the most-accident prone sites in the city.

Speaking of massive projects:

The diverging diamond of I-88/Route 59 is part of an almost $90 million three-mile widening of Route 59. It appears well likely to meet its two-year construction goal. Meanwhile, the $50 million overhaul of the Route 20/McLean Boulevard intersection in Elgin is headed for its fourth year of construction.

Mayor David Kaptain said this past week that state officials told him the only way to get the project done as planned this fall would be to narrow McLean to one lane in each direction. That, he said, would result in traffic backups "all the way to Larkin High School, and all the way to Wing Street, every night. So we told them we can't do that."

If traffic were to stretch to Wing Street, that's about two miles of backup.

Good idea to finish next spring.

jdavis@dailyherald.com

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