Any point where a railway crosses a road at the same elevation (i.e., without a bridge or tunnel). Level crossings are where you're supposed to "watch for flashing lights" and/or "stop, look, and listen." (Cheese bus drivers tend to do both.)

Every year, more and more drivers have been killed in attempts to outrun oncoming trains, and this has led to new level crossings with medians and four-way gates, which corral oncoming cars and prevent them from driving around or through the crossing while a train is approaching.