Final answer:
Trucks carrying explosives must signal their breakdown by placing warning devices at certain distances, which vary by jurisdiction. These signals are to be placed in front and behind the vehicle, and on the traffic side facing oncoming traffic, to ensure safety of all road users.
Step-by-step explanation:
When it comes to the safety measures for trucks carrying explosives that have broken down, there are specific regulations that must be followed to ensure both the driver's safety and that of other road users. These trucks must signal their presence to others on the road by placing warning devices at certain distances. Unfortunately, the initial question does not provide the specific distances required for the placement of these signals.
To answer the question based on general safety guidelines, drivers are usually advised to place reflective triangles or flares to signal a broken down vehicle. Typically, these would be placed both in front of and behind the broken-down vehicle. Although the exact distances can vary depending on the jurisdiction, they are commonly set at intervals that allow oncoming traffic to react appropriately. A third signal is often recommended to be placed on the traffic side of the truck a certain distance away, in the direction of oncoming traffic, to provide additional visibility.
It's important to note that this answer does not contain specific distances because the question as posed did not provide necessary regional or legal guidelines that dictate these distances. Therefore, for the precise legal requirements, one should consult the vehicle code or transport regulations applicable to the area where the breakdown occurs.