What defines merging in traffic terms?

Merging in traffic terms refers specifically to the combining of two traffic streams into one. This process often occurs on highways where vehicles from an on-ramp need to enter the main flow of traffic. Effective merging requires drivers to assess the speed and distance of both their own vehicle and the surrounding vehicles to safely integrate into the existing lane. This action is critical for maintaining smooth traffic flow and preventing congestion, especially during peak travel times.

The other options do not accurately represent the concept of merging. Slowing down may occur during the merging process, and a sudden stop is typically not part of merging, as it can disrupt the flow of traffic and pose safety hazards. Making a left turn is a distinct maneuver unrelated to the concept of merging.