Say that you are taking pictures from a street like this one:
As you can see, the picture is taken perpendicular to the direction of the street.
The problem is that cars at the left look as if they are going East South:
And cars at the right look as if they are going East North:
Only when they're right in front of you, the cars look like going simply East:
As I understand, the name for this phenomena is called "Horizontal Convergence". How could you remove this phenomena from a picture? That is, how can I transform the image so that all the cars look like going simply to the East no matter their horizontal position.
To read about a "vertical congergence": https://digital-photography-school.com/how-to-overcome-the-problem-of-converging-verticals/