Final answer:
If a railroad grade crossing has no warning devices or only a crossbuck sign, you should stop within 100 feet of the railroad crossing.
Step-by-step explanation:
If a railroad grade crossing has no warning devices or only a crossbuck sign, you should stop within 100 feet of the railroad crossing.
This is because the crossbuck sign indicates that you are approaching a railroad crossing and you must prepare to stop if necessary.
It is important to exercise caution and be prepared to yield to any approaching trains.