There are of course exceptions to this rule - a pentagonal County Route marker isn't (typically) a greater threat than a standard square route marker, and even though they have only 3 sides, the YIELD and No Passing Zone signs are still rather important (and the pennant shape of the NPZ sign serves as a sort of "get ...
Answer:
Railroad crossing is one of the deadliest types of intersections.
The four characteristics of a state in the United States are territory, population, government, and sovereignty.