Roof Crush

Each year, an estimated 7,000 people are fatally injured in roof crush rollover accidents. That's not to count the 250,000 plus rollover accidents with non-life threatening injuries.

While their European counterparts are busy building vehicles with roofs that withstand more force and weight, the big three automakers in the United States are doing little to improve their roof crush standards and are still following 30 plus year-old guidelines for safety. With cost and fuel efficiency in mind, not safety, American auto manufacturers are doing everything they can to convince those in charge of federal roof crush regulations to stay silent.

SUVs are more likely to rollover due to their height and in many, their narrow wheelbase. When a SUV has a weak roof, the resulting roof crush during the rollover can cause serious or fatal brain or spinal cord injuries.

Vehicles are supposed to be designed so that, in the case of a rollover, the roof structure should remain reasonably intact. When the amount of pressure on the roof causes the windshield to break, the roof of the vehicle is weakened by 33 percent. When the windshield breaks, there is a greater chance of vehicle ejection, resulting in far worse injuries. With cheap and inexpensive material in the roof structure and A-pillars, roof crush will result.

Roof crush injuries are some of the most serious including spinal, neck and head injuries.

The average cost to reinforce one vehicle is approximately $50

On March 18, 2005, a Jacksonville, Fla., jury ruled the Ford Explorer's roof was defective and ordered Ford to pay (the plaintiff) $10.2 million for economic damages, pain and suffering.

Company documents presented to the jury revealed the Ford Explorer's roof was weakened when the SUV was redesigned twice in the 1990s -- after engineers recommended strengthening the roof earlier in the decade. Lawyers also used internal company memos that show that Ford's Volvo subsidiary considered roof strength critical to protecting passengers in rollover crashes.

Annual Average Number of Fatal and Serious Occupant Injuries in Towaway Crashes by Crash Type in the 1995-1999 NASS and FARS Crash Databases*

Crash Type

Total
Occupants

Fatalities

Fatalities per
Total
Occupants

Fatal and
Serious
Injuries

Injuries per
Total
Occupants

Rollover

418,371

10,149

0.0243

27,057

0.0647

Frontal

2,921,864

12,384

0.0042

62,536

0.0214

Side

1,359,538

8,169

0.0060

33,610

0.0247

Rear

467,559

1,023

0.0022

2,701

0.0058

Other

36,978

432

0.0117

580

0.0157

Totals

5,204,309

32,157

0.0062

126,484

0.0243

 

Nov 20, 2005 | Detroit News
"Many of Ford Motor Co.'s best-selling Explorer SUVs from the 1999 to 2001 model years likely do not meet a crucial safety requirement intended to protect passengers in rollover crashes, a safety engineering firm claimed in a petition filed with the federal government."

 

Rollover

Roof Crush Tests

Currently, NTSHA requires a static test, known as Safety Standard 216, to every car and truck under 6,000 pounds before it can be sold in the United States. Critics say the test doesn't come close to replicating what happens in a real-world rollover, Roof structure
leading to dangerously weak roofs. Alternative tests (drop and dolly test) can help show how roofs will perform in real world rollovers.

Standard 216 test

The federal roof-crush resistance test required is called the "216" test.

1. A vehicle is placed on a flat surface. 2. A flat, steel rectangular shaped plate is pushed into the vehicle's roof structure. 3. The plate us applies one and a half times the unloaded weight of the vehicle onto the roof.

216 Test
4. During the test, the plate is angled, positioned and shifted to simulate vehicle-to-ground contact on the roof over the front seat area. 5. The plate is placed at various locations on the vehicle's roof, depending upon the slope of the vehicle's roof to put stress on the roof over the front seat. 6. A vehicle complies if the roof crush is less than 5 inches before the maximum pressure is applied.

Inverted Drop Test
This test is a better indicator of A-pillar performance.

1. A vehicle is suspended upside down by steel cables. 2. The cables are adjusted for a specific angle to concentrate force on the key A-pillar, which supports the windshield. 3. The drop height varies from a few inches to a few feet, depending on the force required.

Inverted Drop Test

 

Dolly Test
Automakers have the option of using the dolly test instead of the current 216 test, but few if any use it.

1. A vehicle is placed on a sled inclined at a 23-degree angle and is accelerated to 30 mph. 2. The sled comes to a sudden and complete stop. 3. The test vehicle is forced over a 4-inch block and forced into a rollover. 4. Test dummies inside the vehicle are measured for injuries as the vehicle rolls several times. 5. The roof crush measured in this test will more closely replicate real world rollovers.