When can you move vehicles involved in a traffic crash?

The correct choice is based on the principle of ensuring safety and maintaining traffic flow in the event of a traffic crash. When vehicles are involved in a crash and they are obstructing traffic, it's important to move them to a safer location, if possible. This helps reduce the risk of further accidents and allows other vehicles to pass safely.

While the presence of the police can be important for reporting the accident and gathering information, it is not always practical for them to arrive immediately, especially in busy areas. In cases where the vehicles are creating a hazard by blocking traffic, moving them can prevent additional collisions and facilitate smoother traffic flow.

The option involving a fire hazard is also relevant; however, the primary concern in this context is usually about preventing additional accidents by clearing obstructing vehicles first. While feeling safe to move vehicles is important, it doesn't provide guidance on the urgency in scenarios where traffic is being hindered. Hence, acting to clear the roadway when obstruction occurs is the most immediate and necessary response after a crash.