What is a consequence of inadequate signaling when merging lanes?

The correct choice points to the serious safety risks that arise from inadequate signaling when merging lanes. Signaling is essential in communicating a driver's intentions to other road users. Without proper signaling, other drivers may be unaware of a vehicle's plan to merge, leading to misunderstandings and potential accidents.

Inadequate signaling can result in a higher risk of collisions, as neighboring vehicles may not adjust their speed or position accordingly. This can create confusion on the road, as drivers might react unpredictably, not knowing what actions to expect from others. Consequently, such scenarios can lead to close calls and serious accidents.

In contrast, the other options suggest benefits that cannot occur when signaling is lacking. For example, without clear communication, speed and efficiency cannot improve, nor can travel times be reduced significantly. Instead, poor signaling tends to create a chaotic driving environment, which only increases the likelihood of dangerous situations on the road.