Audible pedestrian crosswalk signals produce sounds that tell people with visual disabilities when it’s safe to cross the street and help them locate the crossing pushbutton. These signals are part of a broader system called Accessible Pedestrian Signals (APS), which combine sound, speech messages, and vibrating surfaces to replace the visual “walk” and “don’t walk” signs that sighted pedestrians rely on. The most recognizable feature is an audible tone or speech message that plays only during the walk interval, but the system includes several other components designed to make every step of crossing an intersection accessible.
The Pushbutton Locator Tone
Before you can cross, you need to find the button. Every APS pushbutton emits a repeating tone, called a locator tone, so a person with a visual disability can walk toward the sound and locate the device. This tone clicks or beeps at a steady rate, typically between 1.0 and 1.2 times per second. Research in the Transportation Research Record found that this repetition rate allowed people to find the pushbutton pole fastest and was strongly preferred over slower rates.
The locator tone doesn’t need to be loud. Studies found that a tone just 2 decibels above the surrounding street noise actually led to faster pole location than louder tones set 5 or 10 decibels above ambient sound. The signal only needs to be about 5 decibels louder than background traffic to be effective, which keeps noise levels reasonable for nearby residents and businesses.
The Audible Walk Indication
The core feature most people associate with audible crosswalk signals is the sound that plays when the walk interval begins. The current recommended standard in the United States is a rapid ticking or beeping sound. This replaces the older “cuckoo” and “chirp” system, which assigned a cuckoo call to one direction and a chirp to the other. The American Council of the Blind explains that this older system caused real problems: people had difficulty remembering which tone corresponded to which street, often didn’t know which direction they were traveling, and birds sometimes mimicked the chirp sound, creating dangerous false signals.
In some situations, the walk indication uses a speech message instead. A typical speech message follows a format like: “Peachtree. Walk sign is on to cross Peachtree.” Speech messages are especially important when two pushbuttons at the same corner can’t be separated by at least 10 feet, because the rapid tick sound alone wouldn’t tell a person which street has the walk signal. At intersections with an exclusive pedestrian phase (sometimes called a scramble light, where all vehicle traffic stops and pedestrians can cross in any direction), the speech message may announce “Walk sign is on for all crossings.”
Federal standards require that the audible walk indication plays only during the walk interval. It does not sound during the flashing “don’t walk” countdown or at any other time, so it gives a clear, unambiguous signal about when crossing has officially begun.
Vibrating Tactile Arrow
Sound alone doesn’t serve everyone. People who are both deaf and blind need a way to know when the walk interval is active. Each APS pushbutton includes a raised tactile arrow that points in the direction of the crosswalk it controls. When the walk signal activates, this arrow vibrates. A person resting their hand on the pushbutton can feel the vibration start and know it’s time to cross. The arrow’s direction also confirms which crosswalk they’re about to enter, reducing the chance of stepping into the wrong traffic lane.
Automatic Volume Adjustment
Intersections are noisy during rush hour and quiet at 2 a.m. To handle this range, modern APS devices use automatic volume adjustment (also called automatic gain control). A built-in microphone continuously samples the surrounding noise level, and the signal adjusts its volume in response. When a truck rumbles past or traffic surges, the signal gets louder. During a nighttime lull, it drops to a quieter level.
Most systems set a minimum volume around 30 decibels and a maximum around 90 decibels. Federal standards cap the automatic adjustment at 100 decibels. This keeps the signal audible in heavy traffic without blasting sound through quiet residential neighborhoods in the middle of the night.
Speech Information Messages
Some APS devices offer more than just a walk signal. When the walk interval is not active, pressing or holding the pushbutton can trigger a speech message that identifies the intersection and describes its layout. A typical message begins with “Wait,” followed by something like: “Wait to cross Broadway at Grand.” If the intersection has unusual features, such as a median island, diagonal crosswalks, or a leading pedestrian interval where pedestrians get a head start before vehicles, the message describes those details too.
California’s traffic signal guidelines also allow for tactile maps of crosswalks to be mounted at the pushbutton, giving a person a physical representation of the crossing they’re about to navigate. These features go beyond the basic “walk now” indication and help a pedestrian build a mental picture of an unfamiliar intersection before stepping off the curb.
Smartphone and Bluetooth Integration
Newer systems are beginning to connect with pedestrians’ phones. Bluetooth beacons placed at intersections can send signals to a smartphone running a compatible app. In one system called StreetBit, helper beacons activate the app within about 20 meters of the intersection, and main beacons closer to the curb (around 8 meters) issue alerts based on the pedestrian’s speed and angle of approach. The alerts can appear as on-screen messages if the person is looking at their phone, or as audio warnings that override music or phone calls. These systems run passively in the background and activate only near equipped intersections, requiring no action from the user beyond installing the app.
How These Features Work Together
A person approaching an APS-equipped intersection first hears the repeating locator tone and follows it to the pushbutton. They feel the tactile arrow to confirm which crosswalk the button controls, then press it. If the walk interval hasn’t started, a speech message may tell them to wait and identify the intersection. When the walk signal activates, they hear the rapid tick or speech walk message and feel the arrow begin to vibrate. The volume of every sound adjusts automatically to stay just above whatever traffic noise surrounds them. Each element handles a different moment in the crossing sequence, so the system works for people with varying degrees of vision and hearing loss.