The parking lot in a neighboring complex has not been cleared for two weeks. No plowing or salting. What can be done to encourage the property owner to clear the snow?
Strictly speaking, Ohio law only requires a property owner to clear snow on public sidewalks (e.g., that border a public road) and the area around a fire hydrant. There is no provision in the Revised Code that deals with an apartment complex owner and a parking lot. However, if a complex owner neglects the property completely, he or she may be allowing a hazardous condition to exist. Arguably, someone might assert that the unplowed snow is a nuisance.
Given that you don't appear to live in the complex, you'll likely be ignored if you simply contact the owner. Your best bet is probably to talk with a resident of the complex and see if he or she is willing to contact the owner and highlight the danger / liability that the owner is creating.