A car's roof is held up by vertical pillars, lettered from front to back, and the A-pillar is the foremost pair — the supports running up either side of the windscreen to the roof. They are critical structural members: they help support the roof in a rollover and frame the windscreen, so they must be strong, yet thin enough not to block the driver's forward view. This creates a design tension, as ever-stronger crash and rollover standards have made A-pillars thicker, which can create blind spots at junctions — a problem designers tackle with clever shaping or, in some concepts, "transparent" pillar displays. The lettering continues with the B-pillar (between the front and rear doors) and the C-pillar (behind the rear doors), with a D-pillar on larger estates and SUVs.
- The roof pillars on either side of the windscreen
- Frontmost of the lettered roof pillars (A, B, C…)
- Vital for roof strength and rollover protection
- Thicker pillars improve safety but can create blind spots