Although most vehicles already come with an event data recorder -- more commonly referred to as a "black box" -- Pittsburgh auto dealers say few if any consumers seem aware they are there.

But that could change under federal regulations issued yesterday that will require automakers to tell owners if their vehicles have an event data recorder starting with the 2011 model year.

In the seconds before, during and after a crash, event data recorders can provide information about a vehicle's speed, whether the air bags were deployed, if the brakes were applied, or if the seat belts were being worn. The devices do not record data unless there is a collision that is severe enough to cause the airbag to deploy. The information can be used to help investigators re-create crash scenes to determine the causes.

About 64 percent of the 2005 model year vehicles already have the equipment and almost all new vehicles built by Ford Motor Co. and General Motors Corp. have the devices.

Local car dealers say that although the existence of "black box" technology has been around for some time, car buyers never ask about them, how they are used or whether a new vehicle has one on board.