In Massachusetts, where must a school bus stop at a railroad crossing if no stop line is present?
Correct answer: C – Between 15 and 50 feet from the nearest rail
A school bus must stop no less than 15 feet and no more than 50 feet from the nearest rail. If a stop line is marked, the bus must remain behind that line. The operator must also open the service door, determine that crossing is safe, and close the door before proceeding.
Source: Commercial Drivers License Manual - March 2025 Version — § 2.15.2, “Warning Signs and Devices”, M.G.L. c. 90, § 15 — Precautions at railroad crossings

