APS technology is constantly improving and new features are being added to help pedestrians with vision and hearing loss get around safely and confidently. Here are some of the main features you should be aware of.
Accessible Pedestrian Signals (APS) have come a long way since the first cuckoo-chirp, pedhead-mounted systems appeared in U.S. cities in the 1970s. Today’s APS are typically described as push button-integrated and come with a slew of features designed to help pedestrians with vision and hearing loss navigate intersections safely and confidently
While many of the features described in this overview are applicable to all APS installations, others are only relevant to certain locations. Intersection geometry, crossing lengths, and pre-existing infrastructure can all impact the features required at a location in order to provide clear, sufficient information to pedestrians.
APS emit an intermittent sound (usually a beep or a tick) that alerts approaching pedestrians to their presence and guides visually impaired pedestrians toward the push button. According to the MUTCD, the locator tone should only be audible 6-12 feet from the push button (Section 4E.12.06), so that pedestrians can still hear the traffic–an important cue even where APS are present.
The MUTCD requires that all APS feature a raised tactile arrow on the push button that points in the direction of the crosswalk controlled by the signal. This helps pedestrians with vision loss to not only confirm their direction of travel and determine which button to press, but to align themselves with their destination across the street in order to cross in a straight line.
When the ‘walk’ sign is on, the recommended audible indication is a rapid ticking or beeping sound. This is based on research that determined the familiar cuckoo-chirp sound often leads to confusion and incorrect decisions about which street has the walk signal. The MUTCD also allows the use of speech messages during the walk phase, such as, “Broadway. Walk sign is on to cross Broadway” (Section 4E.11.18). Polara has an extensive audio library for this purpose, and can produce custom messages by request.
Automatic volume adjustment
APS must be able to respond to the ambient sound around them, getting louder when traffic or other noise at the intersection is high and quieter when it’s lower. This is achieved with a built-in microphone that continuously collects noise samples and varies the volume of the audible indications based on them. The MUTCD recommends that audible indications be set to be a maximum of 5 dBA louder than ambient sound (Section 4E.11.09).
Extended button press
Many APS, including Polara’s iDS, provide additional features, which can be activated by an “extended button press,” meaning depressing the push button for a longer period of time. These features typically need to be configured by the city and can include things like a direction of travel message, increased crossing time, audible beaconing (see below), and selective muting (helpful when there are multiple APS on a corner).
The MUTCD defines audible beaconing as “the use of an audible signal in such a way that pedestrians with visual disabilities can home in on the signal that is located on the far end of the crosswalk as they cross the street”(Section 4E.13.04). If enabled on an APS, there will generally be a louder push button locator tone that plays either only from the destination pole, or “ping pongs” back and forth across the intersection.
Popularized during the Covid-19 pandemic, touchless actuation is an emerging technology that uses radar to allow pedestrians to activate an APS without physically having to touch a push button. When a pedestrian wishes to cross at an intersection with this feature, they simply wave their hand in front of the sensor to actuate the signal.
Remote activation (PedApp)
Polara offers another contact-free way for pedestrians to actuate APS: PedApp. Designed for pedestrians with vision loss but usable by anyone, the smartphone app alerts users to nearby APS and allows them to place a call to the system of their choosing. Once a crossing has been chosen, the volume of the push button’s locator tone will increase, and information about the signal status will then be delivered to the pedestrian via their phone. See our PedApp page for more information.
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