This looks like two photos of the same road, taken from different angles. But it’s actually just the same photo twice.

Apparently, the visual system treats the image as if it were a single photo of two separate roads. The outlines of the two roads are parallel to one another in the two-dimensional image. For that to be the case in the image, the actual roads in the real world would have to be angling strongly away from each other. So, that’s what the visual system infers.