What is important to ensure during traffic control at a crash scene?

At a crash scene, the primary focus of traffic control is to manage the movement of vehicles effectively to prevent further incidents. This includes ensuring that all traffic is adequately redirected or slowed down to mitigate the risk of additional collisions, which can occur due to distracted driving or reduced visibility. By controlling traffic flow, responders not only protect the safety of individuals present at the scene—such as victims, emergency personnel, and bystanders—but also help to keep adjacent roadways clear to facilitate emergency response efforts.

The other choices relate to aspects that may not prioritize safety or effective traffic management. For instance, restricting passage only to police vehicles could hinder necessary emergency response from other agencies or medical personnel. Allowing a free flow of traffic at all times could compromise safety, especially if drivers are unaware of the hazards ahead. Lastly, not using any warning devices would significantly increase the risk of accidents, as drivers wouldn't receive adequate warnings to slow down or change their route in response to the situation.