Kansas City, Mo. ? Engineers say it could take months to repair a busy Kansas City highway ramp after part of it collapsed.

The ramp links westbound Interstate 470 and northbound U.S. 71 to westbound Interstate 435 and carries about 35,000 vehicles a day — many of them Missouri commuters into Kansas suburbs.

The ramp was closed Saturday afternoon when the pavement collapsed. The resulting 34-foot-wide hole could be as much as 200 feet long.

Engineers say a retaining wall that supported the ground holding up the highway came apart after the foundation gave way.

The Missouri Department of Transportation plans to hire the consulting firm that designed the $300 million interchange to design the repairs.