Arlington, VA, April 19, 2007 -- More than 125,000 occupants of passenger vehicles died in crashes during 2002-05 according to a new report from the Insurance Institute for Highway Safety. Most of the victims were drivers. The impacts varied from single-vehicle rollovers on rural roads to multiple-vehicle pileups in urban traffic. Something else that varied was the risk of dying in one vehicle versus another. Some cars, minivans, SUVs, and pickup trucks have much higher driver death rates than others. The average rate in 2001-04 models during 2002-05 was 79 per million registered vehicle years. But the rates in some models were more than twice as high, while rates in other vehicles were only a fraction of the average.
Chevrolet models take prizes for both best and worst. The lowest death rate among more than 200 vehicles is the Astro minivan's 7 per million registered vehicle years. The highest is 232 per million in the 2-door, 2-wheel-drive version of the Chevrolet Blazer, a midsize SUV.
“This range from best to worst has been the pattern since we began comparing deaths by make and model in the late 1980s,” says Anne McCartt, Institute senior vice president for research. “The rates vary not only among groups of vehicles by type, size, and weight but also among individual models within the groups of similar vehicles.”
As high as death rates are in some models, the average rate for all vehicles is going down over time. The average driver death rate in 1989-93 models during 1990-94 was 110 per million registered vehicle years. When the Institute later computed the rates in 1999-2002 models, the average was 87 per million and now it’s down to 79.
“This is a big improvement over time. The rates have gone down about 30 percent since the mid-1990s,” McCartt points out. The Institute computes death rates for drivers only, not passengers, because varying numbers of passengers in crashes of one vehicle versus another would affect the rates. “Though the focus is on drivers, the rates reflect the relative fatality risk for all occupants,” McCartt adds.
KEY TO CHART:
overall: driver death rate per million registered vehicle years
mv: driver death rate in multiple-vehicle crashes
sv: driver death rate in single-vehicle crashes
sv roll: driver death rate in single-vehicle rollover crashes
Death rates by vehicle size and weight: Characteristics that influence vehicles’ death rates include type and body style (2-door car, 4-door SUV, etc.). Another important factor is size. The smallest vehicles in any type/body style group generally have the highest rates.
None of the 15 vehicles with the lowest driver death rates is a small model. In contrast, 11 of the 16 vehicles with the highest death rates are mini or small models, and none is large or very large.
There are exceptions to the general rule that bigger is safer. For example, the driver death rate is higher in midsize sports cars (115 per million) than in mini (107) or small (71) ones.
Another exception is very large 4-wheel-drive SUVs. This group is mostly Ford Excursions, which have a driver death rate of 115 rates in large 4-wheel-drive SUVs and higher than in all but 4 of the midsize and small counterparts.
Ford Excursions so dominate the group of very large 4-wheel-drive SUVs that they push up this group’s average death rate to 76 per million compared with 47 in large counterpart vehicles and 59 in midsize ones. About half of the deaths in 2001-04 model Excursions during 2002-05 occurred in rollover crashes. Vehicle size and weight are strongly related, so it’s not surprising that driver death rates generally are higher in lighter vehicles. For example, the rate in the lightest SUVs is much higher than in the heaviest ones — 131 per million versus 47.
Pound for pound across vehicle types, cars almost always have lower death rates than pickups or SUVs. An exception is that the rate in pickups weighing 2,500-3,000 pounds is lower than in cars or SUVs weighing about the same.
“There’s no ready explanation for this,” McCartt says. “It probably has to do with how light pickups are driven and use patterns compared with heavier pickups.”
Similar vehicles but different rates: Besides death rate differences across vehicle groups, the rates vary within groups of vehicles similar in both body style and size. In almost every size group of 2- and 4-door cars, for example, the rate in the worst car is at least twice as high as the rate in the best one.
Among midsize 4-door cars, the spread is much wider — a rate of 14 per million in the Audi A4/S4 Quattro versus 130 in the Mitsubishi Diamante. The upper confidence bound for the Audi’s death rate is well below the lower bound for the Mitsubishi, which means the lower death rate in the A4/S4 is unlikely to be due to chance.
Rollovers and importance of ESC: Nine vehicles, all SUVs and pickups, have more than 75 driver deaths per million vehicles in single-vehicle rollover crashes, compared with an average of 24 in all 2001-04 vehicles during 2002-05. This higher rate is largely because of their relatively high centers of gravity.
The vehicle with the very highest death rate in rollovers is the 2-door, 2-wheel-drive Chevrolet Blazer (this SUV also has the worst overall driver death rate). Its 134 deaths per million registered years in rollovers compare with an average of 38 in all midsize 2-wheel-drive SUVs and 28 in 4-wheel-drive versions. Not all midsize SUVs have high death rates in single-vehicle rollovers. No driver deaths were recorded in the 2-wheel-drive Lexus RX 330, for example, nor were any recorded in this vehicle the last time the Institute comput-ed model-by-model death rates. This doesn’t mean its rate will be zero every year, but it does mean very low rates can be expected.
The RX 330 and increasing numbers of other passenger vehicles, especially SUVs, are being equipped with standard or optional electronic stability control (ESC). This feature has been shown to significantly reduce the risk of fatal single-vehicle crashes including rollovers.
More evidence of ESC effectiveness is that all but 3 of the 15 vehicles with the lowest overall death rates have this feature, usually standard (the Chevrolet Astro, Honda Odyssey, and Honda Pilot don’t). In contrast ESC isn’t standard on any of the 16 vehicles with the highest death rates, and it’s optional on only 1 (the Nissan 350Z).
How the rates are computed: Institute researchers computed driver death rates in all crashes and in multiple-vehicle, single-vehicle, and single-vehicle rollover crashes for 202 passenger vehicle models (2001-04) with at least 120,000 registered years or 20 driver deaths during the study years (2002-05). Each model’s rate represents the reported number of driver deaths divided by the model’s number of registered years. Data are from the federal government’s Fatality Analysis Reporting System and registration counts from The Polk Company. Exposure varies considerably among the vehicles. For example, the number of registered years for midsize 4-door cars exceeds 11 million. This compares with about 550,000 for very large 4-door cars. Because of this variability, researchers computed 95 percent confidence intervals with upper and lower bounds indicating the precision of the computed rates.
The rates reflect the influences of both vehicle design and patterns of use. Rates are displayed by market group because of the influence of driver demographics and
the increased likelihood of similarity among drivers of similar vehicles. Researchers adjusted each of the 202 vehicles’ rates according to the proportion of deaths of women 25-64 years old (drivers in this group are in fewer fatal crashes per licensed driver). For most vehicles the rates changed by less than 20 percent. These adjustments take away most of the differences among vehicles caused by driver gender, though other demographics still influence the rates.
The Insurance Institute for Highway Safety is a nonprofit scientific and educational organization dedicated to reducing deaths, injuries, and property damage from crashes on the nation’s highways. The Institute is wholly supported by auto insurers.
To read the complete report: www.iihs.org
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