eBird "travelling" counts: from their website:
"How do I record distance traveled when I back-track on traveling counts?
Good question! In this case the total time you spent birding is the most critical component. You should only record the distance traveling in one direction, but you should record the total time you spent traveling both out and back on the trail. This way you are sampling a distinct area over a certain amount of time. Only record birds on the return trip if you suspect that they are new. Be conservative!"
So, if I dawdle on the way "out" along Pighin Rd, then zip back, I submit ONE checklist, with the single distance, not the doubled distance, BUT with the total amount of time to get to the end and back. On the zip back, I usually only record new species or adjust numbers of species seen.
If I dawdle equally both on the way out and then on the way back, putting the same amount of effort both ways, I submit TWO travelling checklists with the corresponding amount of time. (I am an expert dawdler -- any hour birding is worth at least 3 doing chores)
But what usually happens is that I dawdle on the way out, turn around with the intention of zipping back, but encounter something interesting and spend some time at one spot. So, I do a travelling count, as per my first example, and include everything NOT at the dawdle spot; AND I do a stationary count, IF I have recorded all the species at the dawdle spot - subtracting the stationary count time from the travelling count time.
Fortunately, the eBird database does not recognize that I can do more than one count type at the same time. I hope they don't change that ... Also, I like being multiple places at once and overlapping my time on Earth when I am having fun.