Final answer:
Controls at railroad crossings include crossing gates, flashing green lights, crossing guards, and sirens.
Step-by-step explanation:
The controls at railroad crossings include:
- Crossing gates: These are barriers that extend across the road to prevent vehicles and pedestrians from crossing when a train is approaching.
- Flashing green lights: These lights are typically located near the crossing gates and flash to warn drivers and pedestrians of an approaching train.
- Crossing guards: These are individuals who are stationed at the crossing to direct traffic and ensure the safety of pedestrians.
- Sirens: While sirens are not commonly installed at railroad crossings, they may be used in some cases to alert drivers and pedestrians of an oncoming train.