GARDINER – When Gov. John Baldacci’s Chevrolet Suburban crashed last winter, few knew that it had a “black box” recorder. Not even his state police driver knew about the device.

But state police are increasingly using such crash data to validate and bolster their accident reconstructions.

Already, the technology has been used to support negligent homicide charges in Massachusetts. In Maine, state troopers used the data to prove that a motorist involved in a fatal crash drove through a stop sign.

For now, officers can retrieve the final 5 seconds leading to a crash. But they see the day when more data is available.

“In all honesty, we haven’t been able to scratch the surface of what we can retrieve from those vehicles,” said Sgt. Richard McAlister, one of two Maine state police officers trained to retrieve the data.

The system works by retrieving data from the computer that monitors a variety of sensors in determining when to fire an air bag.

That computer, the so-called black box, is not really black, as Sgt. Shawn Currie demonstrated as he connected a small brushed-aluminum box from a crashed Camaro to his laptop computer in his Gardiner office.

Using a $3,000 software package, he was able to recover data showing the car’s speed, throttle, braking and engine RPMs.

The five seconds of data backed up the story of a speeding Camaro cresting a hill, sliding sideways and flipping, giving credence to a traditional accident reconstruction conducted by another trooper.

Troopers have the ability to retrieve data from late-model General Motors vehicles and many Fords thanks to a GM subsidiary, California-based Vetronix, which created software to interpret the raw data. Eventually, troopers hope to be able to retrieve and interpret data from other makes.

New York and the New England states received the event-data recorders thanks to a federal grant obtained by Massachusetts State Police. Other states using the devices include Michigan, Arizona, Virginia, Florida and California, according to the Massachusetts State Police.

In Maine, Currie and McAlister are trained to use the devices. But they retrieve the data only in conjunction with a traditional accident reconstruction. They don’t view the data alone as sufficient for prosecution.

“We’re not totally relying on it. It’s just another tool. It answers some of the questions and gives us a broader picture of the crash,” Currie said.

In Massachusetts, crash data has been used to bolster evidence in five to 10 prosecutions, said Trooper Edward O’Hara from the Massachusetts State Police collision analysis and reconstruction section.

The data supported negligent homicide charges brought against Michelle Zimmermann of Beverly, Mass., who was accused of speeding when she lost control of her 2002 GMC Yukon and crashed into a tree. Her passenger died.

That case is awaiting a trial date.

The crash data also was used in another negligent homicide case brought against Heidi Fraser of Sandwich, Mass. She, too, was accused of speeding in her 2001 Saturn, which was involved in a three-car accident on May 12, 2002.

Her case has been resolved and the negligent homicide charge will be dropped if she commits no offenses during a three-year probation, prosecutors said.

In Maine, the data has not been used in any prosecutions. But its importance was underscored in a fatal crash in which a motorist in northern Maine was accused of driving through a stop sign and colliding with a snowplow, which crashed into another car, killing a motorist.

The motorist told investigators that she stopped at the intersection. But the crash data showed the motorist only slowed down and then accelerated, McAlister said. No brakes were applied.

Confronted with the data, she admitted to making a mistake, McAlister said. No charges were filed in that case, he said.

Vetronix, which is based in Santa Barbara, Calif., says the primary customers of its Crash Data Retrieval System are accident reconstructionists, law enforcement and insurance companies.

Privacy advocates don’t like the fact that data unknown to motorists can be retrieved and used against them. They also fear that the technology could be misused by insurance companies.

The courts will eventually rule on the privacy issues and whether the data can be used as evidence at trial.

Few knew of the existence of the data in Maine until the Feb. 4 crash involving Baldacci on Interstate 295.

The data supported a conclusion that the state police driver was going too fast for the slippery conditions that morning. Baldacci and the driver suffered mild concussions in a collision. The other motorist wasn’t hurt.

The data demonstrated a flaw with the system: It erroneously indicated that Baldacci was unbuckled.

McAlister said Baldacci’s Chevrolet Suburban was one of the first vehicles to show passenger seat-belt status. The cause of the flawed data has never been determined, he said.