The A-Pillar is extremely key to any vehicle. The role it plays is massive. It supports the roof, windshield, door seals etc...

There are many factors that go in to play when positioning the A Pillar. Frontal and side vision is greatly impacted by its placement. It sets the windshield angle which affects the vehicle aerodynamics. The design also determines crash-worthiness.

Now that you have a very basic understanding of the importance of the A-Pillar lets talk about blind spots and obstructions.

There are certain requirements that will determine if an A Pillar has whats called binocular obstruction. It's obvious that monocular exists right. Meaning at least one eye at a time will have its direct line of sight blocked. It's there. In front. What do you expect. The issue becomes whether or not it has a position that blocks the line of sight for both eyes at the same time for the same sighting location. This is a serious issue as this affects the safety of anything in the forward eye shot of the driver.