The Federal Motor Carriers Safety Administration's five-year, $18-million Large Truck Crash Causation Study told us what we already know: car and truck drivers are the cause of most crashes. Not bad weather, not faulty equipment and not poor roads, but driver behavior.

“We're struck by how underwhelming this study was considering how much money they spent,” says Henry Jasny, General Council of Advocates for Highway and Auto Safety. “We got nothing for the money.”

Others are more politic. “Everybody knows that driver actions are more important than anything else,” notes Steve Campbell, Executive Director of the Commercial Vehicle Safety Alliance. “We may not have gotten the biggest bang for the buck.”

Planning for the multi-year study began in January 2000, with collection starting in April 2001; the process ended with a report to Congress in March, 2006. The study looked at 967 crashes involving at least one large truck and resulting in at least one fatality or injury.

The main finding: Action or inaction by the driver of either the truck or other vehicle was the critical reason for 88% of the crashes.

The study did reveal a few surprises, though. Overall, large trucks were responsible for 55% of all crashes, but in two-vehicle crashes involving at least one large truck and at least one passenger vehicle, the driver of the car was at fault about 56% of the time. This seems to contradict the industry's current position that passenger vehicle drivers are overwhelmingly at fault in truck/car crashes. In this study at least, both drivers appear equally culpable.

Another surprise was that fatigue played a much lower role in crashes among truck drivers than previously thought. Indeed, fatigue was indicated twice as often for passenger vehicle drivers than truck drivers. And still another revelation was that prescription drug use was the cause of crashes in about 30% of incidents for both drivers, raw information that needs further analysis.

FMCSA Director of Communications Ian Grossman is quick to point out that this study is not about assigning blame but finding the causes of crashes and fixing them. “This was not a blame-game study,” he says.

Blame or not, the study's detractors are fuming that FMCSA has not yet released the raw data or revealed their methodology, which they deem as fundamentally flawed. “The study is not scientifically founded,” notes Jasny. “When you do a study like this you need a control group, and they didn't do that.” In response, Grossman says: “You can't do a control group in studies like this. There are too many variables.”

Jasny and others may have some of their desires met when FMCSA puts the raw data online perhaps as early as this month. Most of the data will be open to the web-surfing public, and additional information will be available to bona fide researchers who register for access.

But even this move by FMCSA may not quiet those who criticize the study. “FMCSA should have done the analysis of the raw data. That's their job. They were in a rush to put it out,” said one industry official. He and others suggest that FMCSA may have purposely issued a non-controversial and incomplete report because its recent offerings, such as hours-of-service rules, have been so vehemently attacked for allegedly poor methodology and lack of scientific protocol.

The main problem here, critics contend, is that the raw data mainly came from eyewitnesses who are notoriously poor sources of accurate and unbiased crash information. “The consensus among accident reconstructionists is that methodology relying on people's observations is problematic,” says Campbell. “Was there actually good data gathered from the truck itself? I guess we'll find out when FMCSA releases the data.”