A-pillar definition and meaning

An A-pillar is the vertical support structure on either side of a vehicle’s windshield. In many cars, the a-pillars are located at the extreme front corners of the windshield opening. The A-pillars provide critical support for the roof and help to protect occupants in a rollover accident by preventing the roof from collapsing. In addition, the A-pillars can support other safety features such as side curtain airbags. For these reasons, it is essential to maintain the A-pillars’ integrity and avoid making modifications that could weaken them.