BLOOMINGTON - Bob Denny had no idea there was a "black box" in his late model car. "I've heard of them on airplanes but wasn't aware of them on cars," said the retired State Farm Insurance Cos. employee.

Denny, who was waiting for his car at a Bloomington-Normal auto repair shop, isn't alone.

"I think it's a safe assumption that many people don't know," said Rae Tyson, a spokesman for the National Highway Traffic Safety Administration, which will require manufacturers to notify vehicle owners of the presence of devices by 2011.

While "black box" is the common term for the devices, the technical name is event data recorder, or EDR.

Originally, carmakers installed EDRs to help monitor safety and performance functions, such as air bag systems. But other uses have cropped up that could have legal ramifications for vehicle owners.

Police and insurance companies, for instance, sometimes use information from the recorders as part of their investigations into vehicle crashes. The devices determine, among other things, a vehicle's speed just before a crash, whether the brakes were applied and whether seat belts were fastened.

In a recent case in McLean County, an EDR showed a McLean County sheriff's deputy was driving 73 mph in an unmarked car when he collided with a pizza delivery driver late last year at Towanda Barnes Road and Baywood Drive on Bloomington's east side.

The deputy, who did not have his siren or lights on, was responding to a bank alarm. The pizza driver was charged with failure to yield; the deputy was not charged. Both drivers were released from the hospital within days of the crash.

Tyson estimated about two-thirds of the vehicle models sold in the United States come equipped with the devices, which are about the size of a pack of cigarettes and silver in color.

Charles Territo, a spokesman for the Alliance of Automobile Manufacturers in Washington, D.C., said EDRs first began appearing in cars in the late 1970s. He said the majority of late model cars have the devices.

"The primary purpose is to help manufacturers understand how a vehicle's safety systems perform in a crash situation," said Territo, who declined to guess what percentage of the driving public knows the devices are present in their vehicles.

His advice?

"Check the owner's manual," he said.

Different from airplane boxes

While a vehicle EDR works on the same principle as the more commonly known airplane black box, there are important differences.

"There's no voice recording, and it captures only a few seconds before a crash," Tyson said.

There's another difference: While most people are aware of airplane black boxes - they're often one of the first things mentioned in news coverage of air crashes - that's not the case with EDRs.

Bob Dennison, the longtime owner of an auto dealership in Bloomington, said he's never had a customer ask him about black boxes.

Dennison isn't sure he could adequately explain the devices, anyway.

"There's so much nowadays on autos that it takes an astronaut to figure it out," he said.

Dennison Service Manager "Rocky" Griffin doesn't claim to be an astronaut, but he said such high-tech devices are helpful for diagnosing a car's performance.

But their existence as tools for police investigators and insurance companies raises questions for some vehicle owners.

Do police, for instance, need permission to access the information?

Bloomington Sgt. Greg Scott, who works in accident reconstruction, said the department typically gets search warrants to access recorders.

"It's another tool that we can use in conjunction with other accident reconstruction techniques such as measuring skid marks and eyewitness accounts," Scott said.

Tyson, who's aware of such alternate applications for recorders, predicted the courts, Congress, or both, eventually will have to address legal issues surrounding their use. Currently, 10 states have laws on the books regarding EDRs, though Illinois is not one of them.

In the meantime, some observers already have been thinking about the legal implications referred to by Tyson.

"The real concern is who gets the data and how it will be used," said Robert Bradley, a professor of politics and government at Illinois State University.

Bradley sees self-incrimination issues if authorities use recorders against drivers who are unaware of their existence. On the other hand, an EDR "could deter bad driving behavior, but you've got to know that it is there," he said.

ACLU: EDRs worth monitoring

Ed Yohnka, director of communications for the American Civil Liberties Union of Illinois, agreed that how the recorders are used is worth monitoring.

"There are all kinds of emerging technologies that are presented to the public for safety and they end up having some dual use," he said.

Though the ACLU has no official position on the recorders, Yohnka acknowledged that as more people learn about them, concerns may increase.

"While we recognize others might have an interest, … our only interest is for research," Tyson said.

Dick Luedke, a spokesman for State Farm, said while it's "pretty rare" for the insurance company to use information from EDRs, there have been times when they've been helpful.

"When we use them, we hire a professional to extract the information," said Luedke, adding he considers the devices beneficial because they help insurance companies determine the degree of fault in accidents.

"If it is our policyholder, we have a legal right to it (the EDR). If it's a third party we need permission. I don't recall ever seeking a court order," he said.

Mark Messman, a McLean County assistant state's attorney, estimated prosecutors seek information from event data recorders about once a month.

"In almost every fatal crash, we are getting readings," said Messman.

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A few quick facts

Facts about automobile event data recorders, or EDRs:

- About the size of a pack of cigarettes, the recorders are on about 40 million American cars.

- EDRs were originally designed to improve air bag performance based on the severity of a collision.

- The small devices are able to provide information on the vehicle's speed, whether brakes were applied, how fast the accelerator pedal was pressed, whether seat belts were worn, steering angle and what warning lights were on.

- The devices run in continuous short loops, with new information constantly being recorded over old.

- Deployment of an air bag stops the recording. What is then captured is about two eye-blinks worth of information.

- EDR usage varies widely by manufacturer. Most recent GM vehicles have them. Ford is not far behind; every Ford with electronic throttle control since the 2003 model year has an EDR able to record five seconds on either side of a crash.

SOURCES: Alliance of Automobile Manufacturers; the National Highway Traffic Safety Administration; Wikipedia

Equipped vehicles

To see a list of Ford and GM vehicles with this feature, click here.