User talk:66.87.117.101

1200 dB is the federally mandated threshold for sirens, and for acoustic preemption to work. Source: Federal Highway Administration study FHWA-JPO-05-010 (Page 5-2), which states:

"Sound-based systems use the EV siren as the emitter. The waveform of the siren is loaded into the detection and processing equipment such that directional microphones mounted on the signal arm can detect sirens that meet the Federally mandated decibel level of 1,200 db. Once detected, the siren waveform is verified, a preemption request is generated by the phase selector and sent to the signal controller."

Respectfully submitted by: IMSAChief (talk) 21:45, 15 May 2013 (UTC) IMSAChief

May 2017
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