Saw quite a few of these on my western safari in June/July. In Alberta, they're called "Texas gates"--I thought at first that there'd been a spelling mistake, and that the 2nd word should have been "grates"...but then I thought, Nah, Texans would get all huffed by that, thinking it was a verb not a noun, and then with all the guns and all, it would end in tears. So, "gates" it is. (Though I'm sure that for some, Texas grates, too.)
No problems with the cattle grids anywhere, however, happily for me 'n' my Raven:
> quite a few had narrow (4" - 6") plates welded into place to make a track for cyclists, one on each side of the road. No problems with those, obviously, and I was very impressed by some considerate planning. Can't remember where I saw them, but they were quite common.
> some grids had round bars, other squared, the latter easier to ride across, obviously. For the round ones, I slowed down a bit and tried make sure I crossed at 90 degrees. No problems there, though things might have been different in rain or frost.
The one grid setup that was awkward was the bear grid which regulates entry into the campground at Lake Louise. The bars on this grid (that's "bars", the metal tubes, not the Tennessean rendering of "bears") were big 4" things, and widely spaced. First time through, the gate in front of them was open, so I went across them at slow speed, very unsteadily, and was glad to get across without mishap. Second time, the gate was closed, and there was a big sign on it pointing cyclists and pedestrians to the small wicket to the side: seems that the gate opens & closes automatically for motor traffic, and on our first try, we had followed closely after a car & the gate had not yet closed. The trickier thing was that the wicket--a bit like a subway turnstile--was narrow, not easily navigated with a bike with panniers, and had its own compact grid underfoot as well, which was very slick for anyone wearing cycling shoes with hard plastic outsoles; and it was right beside an electrified fence.
I guess it keeps the bears out of the campground. I'm intrigued by the amount of expense and thought that goes into outwitting critters who are just looking for food, after all. There are food lockers throughout the western parks in Canada and the US, to ensure that cyclists and hikers have someplace to store their food, and I'm glad of that. This bear grid was the biggest and most elaborate device I've seen, by some margin. (12-foot chainlink fences are big, of course, but not very elaborate). On the other hand, there's a thriving niche industry in Canada, dedicated to building garbage cans which raccoons can't trash. So far, the raccoons seem to have the designers on the back foot...
