Motorists can expect delays in both directions of Interstate 494 in Plymouth as work begins Tuesday to replace the overpass at Rockford Road.
The current two-lane overpass is being replaced with a new bridge that will feature two lanes in each direction and dedicated left-turn lanes, which don't exist on the current bridge. The project will also include room for pedestrians and bicyclists in each direction.
The construction project will happen in three phases before the new bridge is completed in late-November.
Phase 1 - May 28 through early summer
The first wave of work will begin Tuesday and features both north ramps closing at 2 a.m. That includes the ramp from Rockford Road (County Road 9) to northbound I-494 and the ramp from southbound I-494 to Rockford Road.
Construction workers will be widening the ramps during this stage.
The overpass will remain open, but the primary detour for the closed ramps will push traffic to Hwy. 55.
Phase 2 - Summer through early fall
The second step in the project is to close the bridge to traffic for approximately 100 days. It's during those 100 days that the bridge will be torn down (in June) and the new bridge will go up, eventually opening to traffic.
It's likely that both directions of I-494 will close while the existing bridge is being removed.
Phase 3 - October through late-November
Similar to the first phase, this stage will involve closing the southbound ramp from Rockford Road to I-494 and the ramp from northbound I-494 to Rockford Road. The new bridge will be open to traffic but lane closures could cause delays while construction crews complete the interchange work.
Weather permitting, everything will be done by the end of November.
The current bridge was constructed in 1965 and over the last five years it has averaged 33 crashes on it per year, in addition to significant congestion issues. The new, wider bridge will help with traffic flow frustrations immediately.