What traffic management service is operated by the U.S. Coast Guard to prevent ship collisions, groundings and environmental harm?

The Vessel Traffic Service (VTS) is the correct answer because it is explicitly designed to manage maritime traffic in busy harbors and waterways to prevent dangerous incidents such as collisions and groundings. The VTS operates similarly to air traffic control for aircraft, providing real-time information and guidance to vessels navigating through congested or hazardous areas. This service not only enhances safety but also helps minimize the risk of environmental harm caused by marine accidents.

The other services mentioned do not play a direct role in traffic management on waterways. For example, the Water Safety Management Bureau might focus on broader safety regulations, but it does not specifically handle real-time vessel coordination. The Ship Movement and Safety Agency and the Interdepartmental Harbor and Port Patrol may involve safety protocols or oversight, but they are not recognized as formal traffic management systems like the VTS, which is established and operated by the U.S. Coast Guard. The primary function of VTS makes it a critical component for promoting safe navigation and protecting maritime environments.