It is ineed for making the turn and ending up dead on the line for the ground crew to guide the a/c into the gate. I haven't seen this before in US Domestic terminals but at SFO
's International terminal they do have these. My guess is that it's for a/c in tight
areas where the chance of clipping a wing is high but then again you'd think the chance of that happening would be high at any gate with any a/c of any size!
When I looked at it a circle wasn't the first thing that came to my mind