D Alex,
Sorry, I could have been more clear. I was asking whether US 4-quadrant gates were also timed that way. Bostontrainguy answered my question. I asked because I have never seen a US 4-quadrant gate that I remember. I have seen the whistle-ban-approved arrangements with the high median strip for a while before the tracks, for example between Salt Lake City and Ogden, but that's it. Mostly I've just seen the typical two-gate American grade crossings, plus just lights and just crossbucks.
I can't tell you about typical European gates because I am only a temporary resident here in Oslo. I grew up in Boston and live in Terre Haute. The particular barriers I was looking at were similar to American ones -- just one of gate a couple feet off the ground. I say one level because instead of the single board typical of the US the gates were made of a couple of tubes maybe six inches apart, connected with a kind of lattice of other tubes, but the effect was the same as a board: a barrier a few inches wide at about car hood height. It was not one of those tall gates I have seen pictures of other places. Elsewhere in Olso I have seen gates just like American ones--on a subway line with grade crossings. I can't remember what kind of gates there are on the intercity rail network, where I haven't seen many grade crossings.