Toyota Motor Corp. wants to clarify how it uses and discloses information from event data recorders (EDR) in Toyota and Lexus vehicles, according to a statement it released Friday.

The data that is recorded and that can be read out and analyzed differs depending on the type of EDR that is installed in a particular vehicle and when the vehicle was manufactured, Toyota said.

In general, EDRs were first introduced to record post-crash data, primarily on airbag deployment. In the United States, Toyota started phasing in EDRs into its vehicles in 2001 and has had EDRs in all vehicles from the 2007 model year forward. However, the timing in which the EDRs were introduced into specific Toyota and Lexus vehicles varies from model to model.

Although there are a variety of EDRs installed on Toyota and Lexus vehicles in the U.S. today, EDRs can generally be split into two groups: those that record only post-crash data, and those that record pre- and post-crash data. In both cases, the EDRs record data only for collisions that meet certain criteria that are based on the severity of the collision.

Toyota said it provides authorities with both raw readout data and a printout of the readout. In some cases, data columns have been blank because data for the column did not exist due to the specifications of the EDR installed in the vehicle concerned.

The software used to “read out” the EDR data, in some cases, is still in a testing phase and is not yet compatible with all electronic control units (ECUs) in use in Toyota and Lexus vehicles.

Toyota is currently working on upgrading the “read out” software so it will be compatible with all vehicles, and plans to complete this effort by the end of April 2010.

Concerning the specialized computers used to extract the EDR data, Toyota delivered one unit to NHTSA on March 3, 2010 and another three will be delivered to NHTSA in April. By the end of April, 150 units will be available in North America. Once the additional read-out units are available and appropriate procedures are in place, Toyota said it will provide vehicle owners with access to EDR data from their vehicles upon request.