TRB’s Transit Cooperative Research Program (TCRP) Research Results Digest 84: Audible Signals for Pedestrian Safety in LRT Environments examines the application of audible signals for pedestrian safety in light rail transit (LRT) environments. The report includes descriptions of audible signal systems and associated operating procedures, their integration with other crossing measures, potential criteria for their use, and their likely effectiveness and limitations. Details of a survey that was used to help develop this report was published as TCRP Web-Only Document 35.