Motorists will encounter periodic ramp closures at the Interstate 35/Interstate 90 interchange in Freeborn County beginning Tuesday as crews set poles and install lighting.

Motorists should follow the posted detours. All ramps will be open by Sept. 26, weather permitting.

The upgraded intersection lighting will improve safety at the I-35/I-90 interchange.

Mankato Electric Inc. is the prime contractor for the project.