About Warning signs J: triangle, not a command: which statement is WRONG?
Sign J8 (dangerous crossroads) itself regulates who has priority at that crossroads.
A warning sign imposes no fixed speed; you must adjust your speed yourself so that you can stop within the distance you can see.
J10 = level crossing WITH barriers. Dangerous crossroads is J8.
J16 = roadworks. Level crossing with barriers is J10.
Explanation
trap: warning confused with a regulating sign. **J-signs are warning signs, not order/prohibition signs**; J8 only warns, it does not regulate priority — that follows from B-signs, shark's teeth, or the main rule