The increasing computerization of cars allows them to capture and transmit data that can help improve highway and driver safety, federal officials said.

But the technology also raises privacy concerns about the ownership and unintended uses of that data, experts said.

The National Highway Traffic Safety Administration is seeking a law that would require automakers to install "black boxes" in every new car and light truck sold starting September 2014. But unknown to their owners, many vehicles already carry event data recorders, or EDRs. The NHTSA estimates that about 96 percent of all 2013 vehicles have the devices.

The recorders, typically triggered by a crash or air bag deployment, can produce data generated shortly before and during a crash, including vehicle speed, whether the brake was used and whether the driver's seat belt was buckled. The device records data from a variety of vehicle sensors and typically is attached to the floor.

"EDRs provide critical safety information that might not otherwise be available to the NHTSA to evaluate what happened during a crash — and what future steps could be taken to save lives and prevent injuries," said David Strickland, the agency's administrator, in a statement.

But privacy advocates say the technology is a new source of data collection on consumers.

For example, some auto insurance companies are offering onboard devices that monitor mileage data and other driver behavior, often in exchange for discounted rates.

"It is going to be harder and harder for people to ever get off the grid. There are so many ways now that you can be monitored," said Thaddeus Hoffmeister, a University of Dayton associate professor of law.

The Electronic Privacy Information Center, a Washington D.C.-based public interest research group, has urged the NHTSA to adopt comprehensive privacy safeguards for vehicle owners and operators, including driver ownership of data, limitations on disclosure and better security for the data collected.

The proposed law would require the recorders as mandatory equipment in vehicles that weigh less than 8,500 pounds. The proposal also includes standardized data collection requirements and mandates that automakers provide a commercially available tool for copying the data.

The law would make it possible to seek civil penalties for failure to provide an event data recorder or one that performs properly.

The cost per recorder is estimated to be $20 per vehicle, because the devices capture data that is already being processed by the vehicle.

The NHTSA said it would treat recorder data as the property of the vehicle owner and it would not be used or accessed by the agency without owner consent.

The Alliance of Automobile Manufacturers said it does not object to the concept of requiring all light vehicles to be equipped with EDRs, but it "strongly opposes" a law to impose such a mandate. Most alliance members have voluntarily installed the recorders in their vehicles for many years, officials said.

Some automakers, including General Motors, have been installing car "black boxes" since the 1990s to help measure and improve the performance of vehicle safety equipment.

Electronic data recorder evidence has been accepted by courts in at least 19 states, as well as in federal court, in cases involving crash investigations, according to Harris Technical Services, a Florida-based crash reconstruction firm.

WHAT CAR 'BLACK BOXES' RECORD

• Date and time of crash

• Vehicle speed

• Engine speed

• Steering angle

• Throttle position

• Braking status

• Force of impact

• Seat belt status

• Air bag deployment

SOURCE: NHTSA