In what circumstance is it safe to merge into traffic?

Merging into traffic is safest when the lane is clear, as this allows for a smooth transition without endangering yourself or other drivers. When you merge into an open lane, you reduce the risk of collisions, as it ensures that the space is available for your vehicle to enter without having to force other vehicles to adjust their speed or position.

While seeing other drivers is important for understanding the flow of traffic, it does not guarantee that there is room for your vehicle. Similarly, merging when traffic is slow could still pose risks if there is not enough clear space to maneuver safely. The key element in merging is the availability of a clear lane, which provides a safe environment for both the merging driver and those already on the road.