Rollovers and Roof Crush Lawyer

Automobile manufacturers have long known how to design vehicles to resist rollover. For example, in the 1970s, Nissan engineers published an article about “overturning immunity.” Overturning immunity essentially means that a vehicle will not roll over on a flat, level road. Nissan explained that its vehicles had achieved overturning immunity.

In the 1980s, however, the sales of sport-utility vehicles began to skyrocket. Manufacturers scrambled to design and manufacturer vehicles of this type as quickly as possible. Many manufacturers took pick-up truck designs and added a roof and seats for the bed. Many manufacturers also offered these vehicles in two-wheel drive, as they were never really meant to be taken off-road. These three factors combined to create a rollover epidemic.

In order to understand the rollover epidemic, you need to understand something about vehicle dynamics. A rough and simple estimate of a vehicle’s rollover resistance is called t/2h. The “t” means track width and the “h” means the height of the center of gravity of the vehicle. Track width is how far the tires are from each other. The center of gravity is like the tipping point. The higher the vehicle, the higher the tipping point. To understand how these things affect rollover resistance, think of a deck of cards (in their box). If we lay the deck flat on a table, then it has a wide “track width” because its “tires” are far apart. It also has a low center of gravity because its weight is evenly distributed and the deck of cards is very low in comparison to the track width. The deck is much wider than it is high. You can push that deck from the side, but you’ll never get it to tip over.

Now look at the opposite extreme. Turn the deck of cards on its side, so only the thin side is touching the table. Now it’s much higher than it is wide. The “track width” is very narrow because the “tires” are close together. The center of gravity is very high because the deck itself is high. This deck will tip over with a slight push. Relative to the track width, the center of gravity is just too high to make the deck of cards stable.

In general we want our vehicles to have a low center of gravity and a (relatively) wide track width. This is a very simplistic example, and vehicles are much more complicated. The suspension system and the tires have a significant effect on rollover resistance and so does the weight distribution within the vehicle. On the deck of cards, the center of gravity is halfway up the deck because the cards weigh the same at the bottom, middle and the top. If we attach something heavy to the bottom of the deck, we make the deck more stable and lower the center of gravity; if we attach something heavy to the top of the deck, it becomes even more unstable and the center of gravity rises higher.

When manufacturers scrambled to design sport utility vehicles in the 1980s, many of them started with pick-up truck platforms. Pick-up trucks are not the most stable vehicles to begin with. If you add more weight up top by putting in seats and a roof over the bed, you make the vehicle more unstable. If you remove the four wheel drive mechanism, you remove a lot of weight from down low, which again makes the vehicles more unstable. Pretty soon, you’ve lost overturning immunity and you’ve created an epidemic.

The epidemic was exacerbated by manufacturers who encouraged a false sense of safety. For example, many car dealers started putting larger tires on their SUVs, increasing the illusion of safety, but in reality making the problem worse by raising the center of gravity. Many SUV manufacturers marketed their sport-utility vehicles as “safer.” They encouraged the belief that bigger, heavier SUVs protected occupants in crashes, that riding up high increased visibility and that SUVs protected against bad weather and bad roads. Many drivers still believe these claims. Many SUV owners believe they are safer. Manufacturers encourage and exploit this “illusion of safety.” Death and injury rates, though, tell the tale.

The simple fact is that sport-utility vehicles are among the most dangerous vehicles on the road. Handling is cumbersome and braking is slow – some SUVs need more than 40 extra feet to stop when decelerating from 60 mph. This leads to many more collisions that could have been avoided, and SUVs pose extra dangers in those collisions. Cars crumple in an intended predictable mode of deformation during head-on collisions, which absorbs some of the force and protects the occupants. SUVs generally have truck frames that magnify the force on the occupants. Incredibly, some car dealers under-inflate the tires because they know most SUV drivers never take the vehicles off road. This smoothes out the rough SUV ride, but it causes significant stability problems and increases the chance of rollover. It also leads to tire delamination. The bottom line is that rollovers in sport-utility vehicles are as much as five times more deadly than accidents in other vehicles.

ROLLOVERS AND SEATBELTS

Once a vehicle rolls over, the occupant faces other dangers. For example, some seatbelts are not designed well enough to restrain occupants during rollovers. If the occupant is ejected, the likelihood of death or paralysis rises exponentially.

ROLLOVERS AND ROOF CRUSH

Even if the occupant is restrained by a well-designed seatbelt system, the occupant faces the danger of roof crush. Once the vehicle rolls, the roof comes in contact with the ground, sometimes multiple times. Sometimes the vehicle lands on its roof. If the roof is not strong enough, the roof will crush into the space where the occupant’s head should be. The result is often a broken neck.

BE CAREFUL

If you’re considering buying an SUV, please be careful. Some SUVs are well designed and have reasonable rollover resistance. Many do not. You can look at crash test data and rollover ratings in our vehicle safety file.

If you or a member of your family has been in a rollover accident, contact us immediately.