Problem Statement
Transit vehicular warning horns are relatively omni-directional and can be a source of annoyance in areas of the community adjacent to rail lines. For example, train horns sounded before grade crossings can have significant impact on nearby neighborhoods. In some cases whistle bans have been enacted, but with the unfortunate consequence of increased accidents. More directive horns can “focus” the sound toward the ideal target area while minimizing community impact in other directions.
 
Proposed ResearchDesign and demonstrate examples of directive warning systems for locomotives and transit vehicles consisting of phased arrays of horns using well-established array theory. Establish practical trade-offs between the degree of directivity achieved, ruggedness, and cost. These designs can then be assessed both theoretically and empirically in terms of community noise reduction so that they can provide standard measures, including LMAX,   SEL, LEQ, and DNL for a variety of transit vehicles.