I'm pretty new to the state signage conventions, so please don't crucify me for this likely-dumb question:
Around the I-471 area, why is I-275 signed as "To Columbus" as opposed to "To I-71/75N"? I suppose most through traffic from the 471 area would likely be using it as a 71 bypass as opposed to a 75 bypass, but the way it is currently signed might make first-timers think that it continues all the way to Columbus. It's one of those little things that has bugged me for years.
There are a few reasons for this, some of which have been discussed on this forum so I don't expect you to have heard before.
1) Almost a universal stance around here, I-275 is not a good bypass for I-71 or I-75. It goes too far out of the way to be realistically functional for either. Most people traveling thru on 71 or 75 just take it right through downtown. It also is faster to take 471 from 275 than it is to stay on 275 all the way to 71. Now if you're going from 74 to 75, or OH-32 to I-71, then 275 is actually functional.
2) Control cities are aimed at providing a route to a destination. My wording is not the best so maybe this example will clear it up. At the north end of I-459, where it meets I-59, if you are traveling south on I-59 you'll see I-59 signed for Birmingham and I-459 signed for Montgomery and Tuscaloosa. Why? Because those are destinations, and ALDOT wants people going to those destinations to use I-459 over I-59. If you put "TO I-59 SOUTH" people might just take I-59 there because it already is I-59 south. Also, I-59 isn't a destination itself, it is a way to a destination but people aren't looking to find a way to the way to the place they're going, they just need directions to where they want to go. DOTs use control cities to influence travel routes.
3) In the case of I-275, the area of concern is much closer to the southern junction with I-71/75 than the northern junction, which is the one you are referring to (I assume). This can lead to confusion as the junction where the two are multiplexed is the southern one, and the northern ones are both 15+ miles further away and in a different state from where the sign would be. Columbus makes more sense as it is a destination and is less confusing. And again, I-471 is the faster route to I-71 and is shorter distance and time wise compared to 275.
4) The northern junction between I-75 and I-275 uses both route numbers and cities. This is likely because both Columbus and Indianapolis (the two cities on the signs) are both controls at the I-70 junction on the north side of Dayton, maybe to avoid deja vu for the motorist. Also, I-71 and I-74 are relatively close to I-75 at the northern junction, so there is less confusion as to what interchange is being referenced.
I hope I was helpful and clear in my response. I don't usually type this much in a post.