Preliminary work begins Tuesday on a $30 million Lytle Tunnel construction project expected to last two years.
State transportation officials say upgrades are needed to bring the tunnel and its mechanical systems into compliance with current fire codes and design standards.
A detailed road closure scheduled is expected to be determined by mid-June.
Officials with the Ohio Department of Transportation say construction will be scheduled to avoid "as much as possible" major Downtown events such as the July 14 All-Star Game, Riverfest, Oktoberfest, Heart Mini Marathon and the Flying Pig.
But the project will require one full weekend closure of southbound I-71. All lanes would be shut down Friday night through Monday morning.
The ramp from the southbound I-71 to Third Street also will shut down for a full weekend and then for a second time for 20 consecutive days.
The Second Street ramp to northbound I-71 will close for 60 consecutive days.
Motorists are advised to detour around the area by getting off southbound I-71 at the Gilbert Avenue/Reading Road exit. From there, they can take Gilbert Avenue to East Eighth Street to Sycamore Street to Third Street, where they can re-enter the highway.
Northbound motorists can travel up Main Street to East Fifth Street to get onto northbound 71.
Lytle Park and portions of Lytle Street also will be closed during construction.
Traffic on Pike and Fourth streets will be maintained, however, parking will be impacted adjacent to the work site.
The project work will be completed in late 2017 and includes:
additional ITS cameras and a fire detection system will be installed allowing for more efficient and safer response to incidents within the tunnel,
upgrades to the tunnel lighting
repairs to the tunnel concrete and tiling
extensive upgrades to the tunnel mechanical systems and ventilation
installation of a new power supply, replacing the existing underground vaults in the Fourth Street sidewalk
moving the ventilation grating to a location conducive to future park plans
installation of new access hatches at several locations within the park limits that will not impact future park plans