What indicates that a lane should not be used for driving?

A solid red X is a clear indication that a lane should not be used for driving. This signal communicates a prohibition against using that specific lane, typically found in areas with multiple lanes, such as highways or roadways with designated lanes for various purposes. The presence of a solid red X alerts drivers to reduce speed and change lanes safely, as continuing in that lane may pose safety hazards or violate traffic regulations.

In contrast, a green arrow generally signals that the lane is open for travel, while a yellow X indicates that the lane should be vacated as it is about to become unusable. A flashing yellow light typically advises caution but does not specifically prohibit lane usage. Understanding these signals helps ensure safety on roadways by guiding driver behavior appropriately.