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Problems with loud audible signals Loud overhead audible signals have been problematic to neighbors of APS installations. In addition, the loud sound of the signal may prevent pedestrians who are visually impaired from:
The WALK indication should normally be audible only from the beginning of the crosswalk, not across the intersection (MUTCD 4E.06, Draft Public Rights-of-Way Accessibility Guidelines 1106.2.3.2, PROWAAC X02.5.2.2.(G)). Draft guidelines require the WALK indication to be 5dB maximum above ambient sounds when measured 36 inches from the device. PROWAAC recommended an exception for intersections where audible beaconing is needed, when the audible beaconing is activated. (See the following section on audible beaconing for further explanation). Draft Public Rights-of-Way Accessibility Guidelines does not address this issue. If used, the speech messages must contain the words 'WALK Sign" and may also contain the name of the street to be crossed (MUTCD 4E.06). The guidance on loudness reflects a change from the expectations regarding setting the volume typical of previous installation of APS in the US. Sound volume levels The pushbutton locator tone and WALK indication are to be between 2dB to 5 dB above ambient noise levels and should respond to ambient sound; the MUTCD specifies a maximum volume of 89dB. The system is to be adjusted so the sound is audible no more than 6 to 12 feet from the sound source, or at the building line, whichever is less. Volume should be individually adjusted at each APS installation for satisfactory performance. top 
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