APS provide essential information to pedestrians who are blind or who have low vision by alerting them to the status of the walk cycle via auditory, visual, and vibrotactile cues.
Accessible Pedestrian Signals (APS) are devices that provide auditory, visual, and vibrotactile information to pedestrians who are blind or who have low vision, who may also have hearing loss, so they can know when they should begin to cross at a signalized intersection. They essentially translate visual pedestrian information to other sensory formats, enabling people with disabilities to navigate cities safely and comfortably.
Although APS have existed since the 1970s (with some devices dating back even earlier), they were not included in the Manual of Uniform Traffic Devices (MUTCD) until 2000. Since then, compounded by an Americans with Disabilities Act requirement for cities to develop “transition plans” to improve access to public spaces, their prevalence in the U.S. has continued to grow.
A new kind of APS
The APS that are recommended today – push button-integrated, with locator tones, visual, audible, and vibrotactile indications – are markedly different from the overhead cuckoo-chirp signals found at many signalized crosswalks. Researchers have found that these two-tone, pedhead-mounted systems frequently lead to incorrect decisions about which street has the walk signal, along with a host of other issues.
By contrast, modern APS like Polara’s iDS are integrated into the push button station and installed adjacent to the crosswalk they signal. These APS provide audible indications (tone and/or speech message) from a speaker within the push button at a much lower volume than the cuckoo-chirp systems. They also provide vibrotactile indications, directional arrows, and other features that have been proven to help pedestrians with blindness or low vision navigate crossings safely.
Functions and benefits of APS
The primary function of APS is to provide pedestrians who are blind, who have low vision, or who are deaf-blind with the same information that is readily available to their sighted counterparts. This includes things like the status of the walk indication (Walk, Don’t Walk, Flashing Don’t Walk/Clearance), the direction of the crosswalk, the location of the destination curb, and the names of the intersecting streets.
The provision of this information, via audible and vibrotactile formats, has been shown to significantly improve crossing performance, enabling more accurate judgments of the onset of the walk interval, fewer crossings beginning during the Don’t Walk or Flashing Don’t Walk intervals, and significantly more crossings completed before the end of the pedestrian clearance interval. At a higher level, it allows pedestrians with disabilities to move about, participate in, and enjoy their communities – just like everyone else.
APS pushbuttons function as the pushbuttons for all pedestrians.
How Accessible Pedestrian Signals work
APS emit an intermittent beep or tick (known as a locator tone) that alerts pedestrians who are visually impaired to the presence of the pushbutton, and guides them towards it. Once they’ve reached the APS, they can use the raised tactile arrow on the push button to confirm that it is the pushbutton for the street they want to cross. (This is especially helpful when there are two APS on a corner as it helps them select the right button to press and listen for.)
As soon as a pedestrian pushes the button, an audible message – “Wait” – will sound. This will repeat until the Walk interval begins, marked by either a different audible message – “Walk sign is on” – or a rapid beep or ticking sound (selected for its detectability in ambient traffic noise). The pushbutton arrow will also vibrate during the entire Walk interval.
When the Walk indication turns off and the pedestrian clearance interval (flashing “Don’t Walk” indication) begins, the button can be set to play the locator tone (required by MUTCD), a different sound, or an audible countdown of how many seconds are left in the clearance interval. The cycle ends when the “Don’t Walk” indication stops flashing and the locator tone resumes its beep or tick sound.
Why APS matter
At some point, nearly everyone will face an injury or disability that limits their mobility. Although APS are generally targeted toward people who are blind or who have low vision, the fact is they benefit everyone by facilitating safe and independent movement through pedestrian networks regardless of age, ability, race, or income. They are a key component of an accessible, inclusive transportation system.
All intersections with pedestrian signals should be upgraded to include APS in order to create streets that are safe and accessible to everyone.
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