Polara’s iNS Accessible Pedestrian Signals (APS) support audible beaconing, which uses an additional speaker mounted at either end of the crosswalk to help pedestrians with blindness or limited vision properly orient themselves and cross an intersection directly and safely. It is especially helpful at complex, skewed, or wide crossings.
What is audible beaconing?
Accessible pedestrian signals (APS) use sound, raised arrows, and vibration, to inform people with blindness or vision loss when the Walk, Pedestrian Clearance, or Don’t Walk indications are on to provide information to cross the street. They typically take the form of a crosswalk push button and are the accessible equivalent to the standard pedestrian signal indications.
Audible beaconing provides additional audible information to pedestrians with limited vision: in addition to telling them when to cross, it tells them where the other side of the road is. As the MUTCD explains, audible signals help pedestrians “home in on the signal that is located on the far end of the crosswalk as they cross the street.” (Section 4E.13.04).
Whether or not an APS has audible beaconing, it emits a tone or beep at regular intervals to help people with limited vision find the button. Known as a Locator Tone, this sound is designed to be audible from 6-10 feet away.
If audible beaconing is activated with an “extended press” (a button press of at least one second), during the next pedestrian Clearance phase, when the orange hand is flashing and pedestrians have a calculated time to finish crossing the street, crossings that have audible beaconing project the locator tone through the external speaker mounted on the pedestrian signal head at the destination side of the crosswalk.
Following the sound of an audible beacon can allow pedestrians with limited vision to cross with confidence.
Are audible beacons effective?
Several studies have shown that APS with audible beaconing help pedestrians with vision disabilities remain within the crosswalk all the way across the street without veering into the roadway. In one study comparing standard APS with beaconing APS at a complex intersection, blind pedestrians followed the crosswalk 68% of the time with an APS beacon, compared to 36% of crossings with standard APS.
By providing an audible signal to home in on, audible beaconing can give pedestrians with blindness or low vision confidence that they are not veering toward the intersection.
Where and how should audible beacons be used?
According to the MUTCD, audible beacons should be considered at crossings longer than 70 feet with no median divider, at complex, skewed, or irregular intersections, and at any intersection where an engineering study or a request from a person with vision disabilities suggests beaconing would be helpful.
Audible beacons are not needed at all crossings with APS, nor at all crosswalks at an intersection. It may be that there is only one crossing at an intersection where there is no vehicular traffic going parallel with the direction of the crosswalk. There is no reason that the other crossings at that intersection should automatically have audible beaconing.
To address noise concerns, audible beacons should activate only when requested by a pedestrian by an extended button press, should only activate during the pedestrian clearance phase, and should amplify the Locator Tone to a maximum of 100 dBA. (MUTCD 11th ed., section 4K.05)
The external speaker used for audible beaconing should be mounted within the width of the sidewalk, 7-10 feet above the pavement. A typical installation is mounted on the pedestrian signal head for that crossing.
What is a user’s experience?
A pedestrian who is blind or who has low vision hears a locator tone as they approach a corner. So they know they need to push a button, and they can find it because they can hear it. They push the button and hold it in more than one second. They know that if they hold the button more than one second, the APS will provide all the features that it’s able and programmed to provide, including audible beaconing.
If the APS is pushed and held during the steady or flashing hand indication, and is programmed to provide intersection information, it will give a message patterned after “Wait. Wait to cross Howard at Grand.” Then it will revert to the quiet locator tone until the onset of the WALK interval. During the WALK interval, it will provide a rapid percussive tone and the tactile arrow will vibrate. Or, if two APS on the corner are not at least 10 feet apart, it will provide a speech indication patterned after “Walk sign is on to cross Howard.”
When the pedestrian clearance interval begins, the pedestrian will hear a loud locator tone (audible beacon) coming from the loudspeaker at the opposite end of the crosswalk once per second. It is important that the audible beacon be the required very brief percussive sounds of the locator tone, and not an audible countdown. The percussive sounds of the locator tone are more easily located than speech, and loud speech is much more likely than loud locator tones to interfere with the ability to hear conflicting traffic. The walk indication also comes from the APS pushbutton at both ends of the intersection at its usual, relatively quiet, volume.
If the pedestrian has been able to begin crossing at the onset of the walk interval with no delay, they are likely to be entering or in the second lane of the street at the end of the walk indication. They then should be able to hear the audible beacon and they can adjust their heading, if necessary, and continue crossing the street heading toward the audible beacon.
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What does the MUTCD say about audible beacons?
2009 ed. MUTCD section 4E.13:
Support:
Audible beaconing is 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.
Not all crosswalks at an intersection need audible beaconing; audible beaconing can actually cause confusion if used at all crosswalks at some intersections. Audible beaconing is not appropriate at locations with channelized turns or split phasing, because of the possibility of confusion.
Guidance:
Audible beaconing should only be considered following an engineering study at:
A. Crosswalks longer than 70 feet, unless they are divided by a median that has another accessible pedestrian signal with a locator tone;
B. Crosswalks that are skewed;
C. Intersections with irregular geometry, such as more than four legs;
D. Crosswalks where audible beaconing is requested by an individual with visual disabilities; or
E. Other locations where a study indicates audible beaconing would be beneficial.
Option:
Audible beaconing may be provided in several ways, any of which are initiated by an extended
pushbutton press.
Standard:
If audible beaconing is used, the volume of the pushbutton locator tone during the pedestrian change
interval of the called pedestrian phase shall be increased and operated in one of the following ways:
A. The louder audible walk indication and louder locator tone comes from the far end of the crosswalk,
as pedestrians cross the street,
B. The louder locator tone comes from both ends of the crosswalk, or
C. The louder locator tone comes from an additional speaker that is aimed at the center of the
crosswalk and that is mounted on a pedestrian signal head.
11th ed. MUTCD (December 2020 draft), section 4K.05:
Support:
Audible beaconing is 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.
Not all crosswalks at an intersection need audible beaconing. Audible beaconing is not appropriate at locations with channelized turns or split phasing, because of the possibility of confusion.
Guidance:
Audible beaconing should be considered following an engineering study at:
A. Crosswalks longer than 70 feet, unless those crosswalks are divided by a median that has another accessible pedestrian signal with a locator tone;
B. Crosswalks that are skewed;
C. Intersections with irregular geometry, such as more than four legs;
D. Crosswalks where audible beaconing is requested by an individual with visual disabilities; or
E. Other locations where a study indicates audible beaconing would be beneficial.
Guidance:
If audible beaconing is used, it should be initiated by an extended push button press.
Standard:
If audible beaconing is used, the volume of the push button locator tone during the pedestrian change interval of the called pedestrian phase shall be increased to a maximum of 100 dBA, and shall come from a loudspeaker that is mounted at the far end of the crosswalk at a height of 7 to 10 feet above the pavement.
Guidance:
The audible beaconing loudspeaker mounted at the far end of the crosswalk should be within the width of the crosswalk.
Support:
When the locator tone is active during the pedestrian change interval at a traffic control signal or pedestrian hybrid beacon where audible beaconing is used, both the audible beaconing loudspeaker and the accessible pedestrian signal emit the tone.