WASHINGTON, Aug 21 (Reuters) - The U.S. government will not require recorders in autos but said on Monday that car makers must tell consumers when technology that tracks speed, braking and other measurements is in the new vehicles they buy.

The National Highway Traffic Safety Administration regulation standardizes recorder content and sets guidelines for how the information should be disclosed. It also requires recorders to be more durable.

Privacy experts complained that consumer interests are not fully protected and information captured by recorders can be exploited.

Safety experts, consumer groups and insurance companies have long pressed the agency to mandate recorders in cars, but industry has responded voluntarily in recent years. About two-thirds of the new vehicles now produced each year contain the device that is connected to air bag systems. General Motors equips all its vehicles with recorders, a company spokesman said.

Regulators sought on Monday to set basic standards for their use, saying that uniform safety data will help make future auto safety regulation more precise.

Automakers have until Sept. 1, 2010, to comply with the notification and other requirements in the new regulation, if they choose to equip their vehicles with recorders.

The rules governing auto recorders, which are similar to the "black boxes" that store information about mechanical flight systems on commercial airliners, are intended to give law enforcement, emergency medical personnel, auto companies and safety regulators a minimum set of mechanical measurements in the seconds leading up to and during a crash.

Under the new rules, auto recorders must track vehicle speed, acceleration, and deceleration, braking, steering and some air bag functions. In some cases data on vehicle roll angle, steering inputs, and passenger safety belt use will be recorded.

Privacy experts criticized the decision to use the owners' manual to notify consumers that the vehicle contains a recorder, arguing that many people do not look at it. They also raised concerns that data could be misused for legal or insurance purposes.

"They basically punted on the privacy issues," Jay Stanley, a privacy expert with the American Civil Liberties Union, said of the NHTSA regulation. "This is a technology that is powerful and rapidly advancing and we need to bring our laws up to date."

Rae Tyson, a NHTSA spokesman, said the owner's manual is suitable for notifying consumers and stressed that recorder information is private property that cannot be downloaded without permission of the vehicle owner.

Tyson said most privacy concerns should be addressed by the courts and Congress, not by NHTSA.