What’s the rationale behind Berkeley walk signal sounds?

Audible walk signal sounds can help orient disabled pedestrians in a variety of ways. Photo: morethanreal

In response to an earlier Ask Berkeleyside post about walk signals in Berkeley aimed to help the disabled, one reader asked a follow-up question about signal sounds, or the lack thereof: “I’m curious about the sound supplements to the buttons. Most of them in Berkeley don’t produce a sound when pushed. Some of them ring. Some of them buzz. Some chirp. Some of them talk. And they don’t seem consistent. Some buzz any time they are touched but produce no other audible sounds. Others seem to be giving other cues. I haven’t been able to figure out precisely what these sounds are meant to signal in all the different configurations.”

City spokeswoman Mary Kay Clunies-Ross said she turned to Berkeley’s Transportation and Disability Compliance staff for the answer.

“The sounds that you hear are called Accessible Pedestrian Signals (APS). The coo-coos and chirps serve as an audible walk signal, with each sound differentiating which street has the walk (cuckoos for north-south and chirps for east-west). Beeps are usually locator tones to help find the buttons without sight. The buzzing sound is used in vibrotactile push buttons, which if held down will vibrate and sometimes include an audible message when it is time to cross.”

Clunies-Ross said Berkeley was an early adopter of these signals, and started installing them in the early- to mid-80s.


“This was far in advance of any regulatory requirements or industry standards so, while Berkeley’s current APSs are largely standardized, there are still a couple of working examples of previous product generations,” she said, via email.

About 98% of local government entities use the coo-coos and chirps, she continued, and the vast majority of Berkeley signals use them, too.

Berkeley’s Disability Compliance staff helps residents and visitors get oriented to the system with written materials and personal assistance.

If something around town has you mystified, write to Berkeleyside at tips@berkeleyside.com (subject line: “Ask Berkeleyside”) and we’ll do our best to track down an answer.