I’ve seen a number of these recently. (Link to Wikipedia in lieu of photos so this’ll post now) https://en.m.wikipedia.org/wiki/Boardwalk
The top photo is what I’m seeing, except often it’s not even elevated, it’s just a wooden path. Though I will say they’re usually a part of trails and not just some random wood. I think people okay them because they are footbridge-y. I reviewed one then saw it in the nearby section for a different review (I’ll admit, I was kinder to that one than others because the photo was amazing).
I’ve been 3*ing these mostly since I haven’t felt like they clearly are or are not eligible. I’ve upped that for some legit nice boardwalks that are actually raised so are arguably bridges. I’ve lowered that for some questionable “that’s just some junk wood on a makeshift path through a neighborhood”.
Boardwalk trails are eligible because they are hiking trails and would fit under the exercise and exploration criteria. I really wouldn't compare them to footbridges though, because not all footbridges (especially those that cross small brooks or creeks) are eligible.
...not all footbridges (especially those that cross small brooks or creeks) are eligible.
I'd personally say these are among the most eligible.
But on the topic at hand, I'd usually approve of boardwalks similar to the one shared, but more examples would be nice. They help connect people to outdoors for exploration & exercise. Sometimes they are to avoid marshy lands and sometimes just provide easier walking paths through woods. I would caution on just accepting any segment, though.
To me, a boardwalk along level ground, I don’t think I would approve, just as I wouldn’t a “footbridge” that is a small piece of wood over a ditch. Ones over wetlands, however, or important grassland, you could also consider a scenic viewpoint.