Not that anyone cares, but I've been avoiding this thread because it blows me away that there's anyone on this planet, let alone posting in this thread, who can't comprehend that a straight arrow pointing directly toward a dividing line indicates that the lane is an option lane that will split between the two indicated destinations downstream of and separate from the divergence indicated by the split arrow. And, conversely, if the dividing line is between two straight arrows rather than directly under one, it means that there's no option lane (or it could mean that the designers didn't know what they were doing, or that there wasn't enough room for a by-the-book way of doing what they wanted to do, but that's a separate issue). That's a matter of my emotional reaction to hard-to-process information. Whatever, Tom.
HOWEVER...My understanding is that, in developing the APL scheme now in use, the concept was tested against both conventional signage and
this Minnesota unisign scheme. Under that scheme, there's no reason for the dividing line to be anywhere other than directly over the option lane arrow because if there's no option lane, they'd use separate signs, as shown
here. The logic of APLs is similar-- just the style of arrow is different.
Personally, I think that the Minnesota scheme is the best of the three, but testing found that it was inferior to APLs. That's why APLs are in the 2009 MUTCD and Minnesota-style unisigns aren't. It just occurred to me that the reason that the Minnesota scheme was found inferior to APLs is that the subset of drivers who are unable to comprehend the meaning of an arrow aligned exactly with a dividing line is a lot larger than I would've thought, and that whatever testing was done didn't pick up on that, possibly because only single splits were tested. It'd be nice to know if that was the case. Circumstantial evidence certainly suggests that not enough effort was put into deciding how to sign two option lane-lane drops in sequence, let alone into communicating a consistent policy to designers.