Anatomy of Roof Design

An A-pillar is a name applied by car stylists and enthusiasts to the shaft of material that supports the windshield (windscreen) on either of the windshield frame sides. By denoting this structural member as the A-pillar, and each successive vertical support in the greenhouse after a successive letter in the alphabet (B-pillar, C-pillar etc.), this naming scheme allows those interested in car design to have points of reference when discussing design elements. The terms are also used by heavy rescue vehicle teams to discuss cutting vehicles open with the jaws of life.

A-PILLAR Definition: The roof support on either side of a vehicle's windshield. B-PILLAR Definition: The roof support between a car's front door window and rear side window, if there is one. C-PILLAR Definition: The roof support between a car's rearmost side window and its rear window. On a vehicle with four side pillars, the rearmost roof support may be called a D-pillar.

Pillar is American English; the British terminology is post.

The NHTSA , National Highway Travel Safety Administration, regulates that the roof must be strong enough to resist force 1.5 times the vehicle's weight before crushing more than 5 inches. Critical support points for this roof crush test are at the pillars of the roof.

The NHTSA is suggesting the regulation be changed to 2.5 instead, which still would permit enough roof crush in a real life rollover to risk head contact. Most vehicles on the road today would only resist an average of 2.3 times their weight before roof crush occurs. The new roof crush regulation would save a handful of lives a year, while there are thousands of roof crush cases each year (26,000+). Consumer groups are suggesting a stronger roof crush standard and a real-world rollover test.

There simply is not enough being done to prevent injuries by roof crush. Tests have shown that vehicles with weak A-pillars can still pass the current and anticipated roof crush tests. Weak A-pillars allows the vehicle's windshield to break, which then allows the occupants or parts of their bodies to exit the vehicle, which can cause serious injuries or death in a rollover. The current and proposed roof crush standards are not enough to prevent serious head injuries to vehicle occupants during a rollover.

Current NHTSA tests use improper angles and dummy placement. In NHTSA tests, the dummy's head is placed towards the B-pillar, while in actual rollovers, the occupants are forced towards the collapsing A-pillar.

Improved roof crush standards would save lives of up to half of those killed in vehicle rollovers, since vehicle ejection due to weak A-pillars is a leading cause of death in rollover accidents.

If you or a loved one have suffered injuries or if you have lost a loved one due to a rollover or roof crush accident , then your time to act is now. Contact us using the link below.