Where should you place reflective triangles when parking on a level, straight two-lane road?

Answer: B — One within 10 feet of the rear, one about 100 feet to the rear, and one about 100 feet to the front.

Placing reflective triangles correctly is crucial for road safety, especially when a vehicle is parked on a highway or road. The recommended placement involves creating a clear warning for approaching traffic. By positioning one triangle within about 10 feet of the rear of the vehicle, you ensure that any driver coming up from behind can see an immediate warning that there is a hazard ahead. The triangles placed about 100 feet to the rear and about 100 feet to the front further enhance visibility and alert drivers at a greater distance, allowing them ample time to adjust their speed or change lanes. This three-triangle setup creates a clear and visible warning area that extends well beyond the immediate vicinity of the stopped vehicle, thereby significantly increasing safety for both the stopped vehicle and oncoming traffic. Other options do not provide the necessary visibility or safety measures. For instance, placing triangles too close together, or only at the front or exclusively behind the vehicle, does not adequately warn drivers from a distance and could lead to unsafe situations. Thus, the placement detailed in the correct answer effectively balances warning visibility for all approaching traffic, ensuring a safer roadway environment.