The team in charge of the new Interstate 74 bridge and its corridors is calling the next few months "the worst stage of the project" for traffic flow.
Major detours, a lane closure on the bridge and a thru-traffic bypass will demand the most of motorists' patience, beginning Monday.
Here are the most impactful changes:
• Iowa-bound Interstate 74 through-traffic will be detoured to I-80 and I-280.
• Traffic heading to downtown Moline cannot use Interstate 74 north of Avenue of the Cities. Traffic will instead be routed off the interstate and onto 19th Street, which runs parallel to and just east of the interstate.
Local traffic then can access the one open westbound (Iowa-bound) lane of the existing bridge from River Drive. The other downtown ramp will not be accessible.
• All on- and off-ramps for Illinois-bound traffic will remain open during the 2019 season.
Beginning Wednesday, weather permitting:
• Local traffic on the Iowa-bound span must exit at Grant Street/U.S. 67 in Bettendorf.
• Through May, traffic in Bettendorf will be rerouted from Grant Street to 14th Street to Kimberly Road, then Middle Road, to continue westbound.
The traffic-pattern changes have long been planned to accommodate the remaining interstate lane expansions in the corridor in addition to the bridge construction.
But Iowa DOT officials in charge of the project also are dealing with unexpected developments.
The erection of the basket-handle arch is essential to the opening of the westbound span. Until the arch is finished, the contractor cannot lay the road surface on the portion of bridge between the arches.
The agreement with lead contractor Lunda Construction had targeted this spring for completion of the arch, which would have made the new Iowa-bound span ready for use in November. But last year's flooding, the anticipated flooding this spring, snows storms, extreme cold and ice in the river have delayed progress on the arches.
Under the circumstances, the new target is to have the westbound span open by the middle of 2020. The plan is to move local traffic onto the new lanes before the opening of the westbound span to through-traffic.
"We are behind at this point in time," said George Ryan, I-74 corridor manager for the Iowa DOT. "To get aggressive now ... we're hoping to buy back time. We will not sacrifice quality to save time."
One recent development that could prove a considerable time-saver is the closure of the few-block stretch of Old River Drive and portions of the adjacent eastern-most end of the Ben Butterworth Parkway in Moline.
The city has given Lunda Construction the OK to stage and assemble portions of the arch and steel girders on the city-owned riverfront land. Having the land at their disposal will make access to and handling of bridge steel much more convenient.
Ryan described the precision needed to erect the arch from either side of the river that is to meet in the middle as being "like putting a Swiss watch together out in the river."
Adding to the pressure is an abbreviated timeline, he said. The entire I-74 project started as an eight-year undertaking, but it was shortened to five years, then condensed to under four years.
"It's a really blistering pace," Ryan said. "Mother Nature certainly has not helped us at all."
It is too soon to say how the ominous flood forecast for the Mississippi River will impact the work zone, he said, but last year's flooding had "a major effect" on the contractor's schedule. High water is especially worrisome from a safety standpoint, he said.
"This is such a great project, and it's going to be hard to remember that when sitting in traffic," Ryan said. "Please: Slow down, be cautious and expect delays."