What are two common overhead obstructions?

The correct answer highlights two significant types of overhead obstructions that operators of vehicles, especially large vehicles like the USN Medium Tactical Vehicle Replacement (MTVR) Dump Truck, must be aware of.

Power lines are a common concern because they can span roads and paths, presenting a risk of electrical hazards if contacted. Trees, particularly in urban or suburban environments, can also become a problem, as their branches may extend over roadways and impede the height clearance for larger vehicles. This awareness is crucial for maneuvering in environments where such obstructions are present, to prevent accidents or damage to the vehicle.

The other choices provide different types of obstructions but do not focus specifically on those that pose a risk from above. While buildings and signs are relevant, they tend to be more about lateral space constraints rather than overhead hazards. Similarly, fences and barriers, as well as poles and vehicles, tend to pertain more to ground-level considerations rather than risks presented by the overhead space that are critical for ensuring safe navigation for larger tactical vehicles.