Jeep Grand Cherokee
According to government and insurance industry statistics, the Jeep Grand Cherokee has a rollover death rate similar to cars and nobody knows why.

High and Mighty: Rollover Rover

Part two of series reviewing Keith Bradsher's High and Mighty.

By EVWorld.Com

It's a mystery that perplexes some of the world's brightest automotive engineers.

For some inexplicable reason that DaimlerChrysler engineers are at a loss to explain, the company's Cherokee SUVs have a rollover death rate that is far below that of their competitors.

So says Keith Bradsher in his controversial new book, High and Mighty - SUVs: The World’s Most Dangerous Vehicles and How They Got That Way.

"The rollover death rate for a Jeep Cherokee is barely higher than for a car, and the Jeep Grand Cherokee's rate is almost as low," he writes.

The issue of SUV rollovers is a thorny one that gets little play in the blizzard of automaker and car dealer advertising that constantly blankets America's airwaves.

Instead, the myth spinners of Madison Avenue subtly imply that these big, heavy vehicles, which can weigh upwards of 6,000 lbs., are somehow intrinsically safer than a conventional automobile. And in one respect this is true.

Bradsher writes...

"SUV occupants do have below-average death rates in collisions with other vehicles, and SUVs are especially effective at protecting the people inside when hit from the side, according to federal and insurance industry data. Yet SUV occupants still have as high a death rate as car occupants or higher. The reason lies in the nemesis of high-riding vehicles: rollovers." [High and Mighty, pg. 148].

Rollover is a phenomenon characteristic of vehicles with high centers of gravity like SUVs. The problem is so acute that Jeep CJ-5's carry a warming label cautioning owners about driving the vehicle on steep inclines.

Bradsher notes that while rollovers account for less than 1 percent of all US auto crashes, they cause twenty-five percent of traffic deaths.

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Every year 10,000 people die from rollovers, more than from all side and rear impacts put together.

In this respect, SUVs have a particularly deadly record. Five of every 100 crashes in a SUV are rollovers. By comparison, a minivan has a rate of 2 per 100 crashes and cars 1.7 per 100 crashes.

During the 1990s, 12,000 Americans were killed in SUV rollovers. According to NHTA another 2,049 died in 2000.

Bradsher continues...

Recent statistical studies, most notably by the Insurance Institute for Highway Safety, have found that the rollover death rate per million registered SUVs is at least double the rate for cars. This is true even if you adjust for such variables as the fact that SUVs are slightly more likely than cars to be driven on rural roads (which tend to be more dangerous than urban roads).

Besides having a high center of gravity, which makes them more prone to rollover than low-slung sedans, SUVs don't mix well with highway guardrails. Where cars will tend to glance off guardrails, SUVs can either ride over them or have their tires ripped off by guardrail posts.

According to Bradsher, studies conducted by the Midwest Roadside Safety Facility at the University of Nebraska in Lincoln demonstrated that standard 27 inch-high guardrails offer little protection for SUVs.

Researchers at the Texas Transportation Institute point out that guardrails work best when struck by the vehicle's metal structure. Because SUVs are intended for use off-road, engineers design them so there is little of the vehicle body that would catch on stumps or boulders. Instead, their tires are generally the first thing that encounters an obstacle, be it a rock or a guardrail.

Problems arise when one of a vehicle's wheels get far enough under the guardrail to snag the pillar holding up the rail. Since the pillars are virtually unbreakable, a snagged wheel either rips off or, if it stays on, anchors that corner of the vehicle to the pillar while the rest of the vehicle swings around. In both cases, a rollover is likely.

As for the Jeep Cherokee conundrum, the rollover death rate for both models is nearly the same as a bigger midsized cars like the Ford Taurus or Pontiac Grand Prix. Drivers of the four-wheel-drive Cherokee died in rollovers at a rate of 15 per 1 million registered Cherokees. Midsized cars have a rate of 14 per million. Two-wheel-drive versions of both Cherokees have somewhat higher rollover death rates of 21 per million. The Grand Cherokee is slightly higher at 36 per million for the 4WD model and 23 for the 2WD version.

DaimlerChrysler attributes the lower rollover death rate to the vehicle’s unique uniframe construction, but this has never been convincingly proven. So, the mystery lingers.

It should be noted that the new Jeep Liberty hasn't been on the market long enough for any reliable statistics to emerge. However, Bradsher observes that both AutoWeek and Auto Bild, the German car magazine, flipped the Liberty during early test drives.

By tragic comparison, the rollover death rate of SUVs in the Ford Explorer and Chevy Tahoe class is 39 per million. Large sedans have a rate of just 9 deaths per million.

Still, Bradsher points out that from the perspective of an SUV owner, the safety record of their vehicles has steadily improved over the decade.

Yet despite the carnage of rollovers, the safety record of SUVs actually improved through the 1990s, to the point that SUVs became practically as safe as cars. For every million registered SUVs on the road in 2000, there were 134 occupants killed in crashes of all types, including those not involving rollovers, according to the Insurance Institute for Highway Safety. The occupant death rate was barely lower for cars, at 126 per million.

For large SUVs, the death rate was even lower, at 104 per million. That was respectable, although still higher than for the average upper-midsize cars like the Ford Taurus and Pontiac Grand Prix and minivans like the Dodge Caravan, for which the combined death rate was 96 per million registered cars.

But were SUVs actually getting safer or were they simply transferring their death rate to smaller, more vulnerable vehicles?

As SUV sales rose through the 1990s, there was a huge bill in blood to be paid for the fashion tastes of the nation's more affluent families. But for the most part, they would not be paying that bill themselves. Instead, they would have the nation's car drivers pick up the tab.

Times Article Viewed: 5619
Published: 19-Oct-2002


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