Accessible Pedestrian Signals (APS)
Janet M. Barlow, COMS
Certified Orientation and Mobility Specialist
Accessible Design for the Blind
Lukas Franck, COMS, GDMI
Senior Special Projects Consultant
The Seeing Eye
The most recent recommendations for accessible pedestrian signals (APS) are based on an entirely different type of device and installation than the overhead cuckoo-chirp type signals that have been installed in many parts of the US. You may be more familiar with the cuckoo-chirp type signals, but they are no longer the recommended standard in the US. This is based on research completed since 1988, including an ACB survey in 1998, evaluating different types of APS systems. First, we learned that the cuckoo-chirp signals resulted in incorrect decisions about which street had the walk signal. People had difficulty remembering which tone was for which direction, often didn’t know which direction they were traveling, and birds sometimes mimicked the chirp sound. In general, this was found to be true for “two-tone” systems of signals; people made incorrect decisions. There was no advantage to overhead mounted signals, in terms of providing directional guidance for crossing, and they had to be louder and were more likely to be disturbing to neighbors. The research is described in Appendix C, in Accessible Pedestrian Signals: A Guide to Best Practice, at www.apsguide.org/appendix_c.cfm.
New kinds of APS
The new kinds of APS are usually called pushbutton-integrated APS. They are a part of the pushbutton and are supposed to be installed near the crosswalk they signal. There are several important features that you should be aware of: pushbutton locator tones, audible and vibrotactile walk indications, tactile arrows, and automatic volume adjustment.
It is important to recognize that the APS information supplements -- but does not replace -- traffic cues. APS provide information only about the status of the signal, so the APS Walk sound tells you that the Walk signal is on, NOT that it is safe to cross. Cars can still be turning across the crosswalk, or running a red light. The APS Walk signal sound can be compared to the "on your mark" instruction at the beginning of a race. It means that the signal has changed, but it is still important to "get set" (check the traffic). Then, after that, if all sounds right, you can “GO” (begin to cross).
Along with the new features of APS, there are new recommendations for installation. Be sure to read the section below on APS locations!
Pushbutton locator tones.
The pushbutton locator tones repeat constantly at once per second, rather like a grandfather clock, to help you locate a pedestrian pushbutton. They come from a speaker at the pushbutton and are supposed to be loud enough to be heard 6 to 12 feet from the pushbuttons, or to the building line, whichever is less. You should not expect to hear the locator tone much before getting to the corner, or during the entire time while you’re crossing the street. The quieter locator tone allows you to hear traffic sounds better. These tones will continue all the time, except during the WALK interval . When you hear this sound, it means you should wait to begin your crossing.
There is a raised tactile arrow either on the pushbutton or somewhere on the housing that is supposed to be installed so that it lines up with the direction of travel on the crosswalk. Basically that means the arrow will be aligned with the crosswalk lines. You can use the arrow to check to be sure the APS is for the street you intend to cross. There will often be two APS on a corner, so you need to be sure you’re pushing the right pushbutton and listening for the right device to sound. Beginning in early 2012, the Manual of Uniform Traffic Control Devices (MUTCD) will require that new APS installations have a tactile arrow on the pushbutton.
However, there are some units that have been installed in recent years that have the arrow on the sign above the button or on top of the device.
So if the APS has a pushbutton locator tone and does not have an arrow on the pushbutton, you might want to search around the button to see if you find a raised arrow.
Audible walk indications.
When the visual WALK sign is on, the recommended standard for the audible equivalent now is a rapid ticking or beeping sound. However, it also might be a speech message saying the street name, then, walk sign is on to cross the street name, as in “Peachtree, Walk sign is on to cross Peachtree”. The audible walk indication usually will repeat for the entire time the visual Walk or ‘walking man’ symbol is displayed.
The rapid tick is supposed to be used at locations wherever the two APS are separated by 10 feet or more and located beside the crosswalk. If it’s impossible to separate the pushbuttons 10 feet or more, a speech message is needed in order to tell which street has the walk. To use the speech message effectively, you have to know the name of the street you’re crossing so additional features are also required.
These requirements are based on research that found the rapid tick to be more detectable in traffic noise and to result in more accurate and faster decisions by pedestrians who were blind. Speech messages seem very user-friendly, but have to be louder to be detected and understood, require users to understand English and know the street names, and result in somewhat slower crossing decisions than when a pedestrian is listening to the rapid tick indications. As mentioned earlier, the research is described in Appendix C in Accessible Pedestrian Signals: A Guide to Best Practice, at www.apsguide.org/appendix_c.cfm.
Figuring out when to cross at an “exclusive pedestrian phase”, sometimes called a scramble light, can be confusing. Here the regulations can allow for a speech message which announces “WALK sign is on for all crossings”, or the rapid tick sound may be installed for all crossings.
Vibrotactile walk indications.
The arrow, on the pushbutton or the pushbutton housing, vibrates for the entire time the visual Walk or ‘walking man’ symbol is displayed. You must have your hand on the arrow in order to feel it.
Automatic volume adjustment.
A pushbutton-integrated APS also responds to sound around it, getting louder when traffic is loud and quieter when traffic is quieter. Be sure that you listen for a fast tick, or a speech message with the street name and the words, “WALK SIGN is on”, and not for a change in volume as a crossing indication. Just because you suddenly hear a louder locator tone, that does not mean it is time to cross.
Audible beaconing is a feature that is included in some APS. It is activated only when pedestrians hold the pushbutton in for more than a second. If audible beaconing is installed, there usually will be a louder pushbutton locator tone during the flashing don’t walk of the next pedestrian phase, on the crosswalk controlled by that pushbutton.
Some additional features may be provided, activated by an “extended button press”. This means that if you hold the pushbutton in for over a second, the APS may then provide a pushbutton information message, audible beaconing, or additional time to cross the street. A pushbutton information message will provide the street names and will begin with the word ‘WAIT’. See www.apsguide.org for information about other possible features.
Location is Important!
The ideal location of pushbutton-integrated APS is on two separated poles, rather than with two pushbuttons on one pole. The US Access Board’s draft guidelines call for the APS to be installed on a pole on the side of the ramp landing, farthest from the parallel street. That means that, if your parallel street is on your left, the APS for crossing the street in front of you is supposed to be on your right. And if your parallel street is on your right, the APS for crossing the street in front of you will be on your left. Understanding those location standards will help you find the correct APS and help your city install them correctly. The location of APS is not very consistent now, but we need to work toward consistency in installation as well as features.
Using APS effectively
(adapted from Barlow, J.M., and Franck, L. (2005) Crossroads: Modern interactive intersections and Accessible Pedestrian Signals. Journal of Visual Impairment and Blindness. Vol. 99, (10), 599-610.)
As stated earlier, it is important to recognize that the APS information supplements -- but does not replace -- traffic cues. APS provide information only about the status of the signal, so the APS Walk sound tells you that the Walk signal is on, NOT that it is safe to cross. Cars can still be turning across the crosswalk, or running a red light. The APS Walk signal sound can be compared to the "on your mark" instruction at the beginning of a race. It means that the signal has changed, but it is still important to "get set" (check the traffic). Then, after that, if all sounds right, you can “GO” (begin to cross).
Crossing at an intersection using an APS:
When using an APS at an unfamiliar intersection, take your time and become familiar with the APS and intersection before crossing. Here are some suggestions for familiarizing yourself to the APS:
Approach the intersection and stop at the curb or curb ramp or street edge, maintaining your initial alignment and check your alignment for crossing by listening to traffic. Even if you hear a pushbutton locator tone before you get to the street, continue to the curb or edge of the street first.
Determine your starting location for crossing, and identify tactile and audible cues to use to realign after pressing the pushbutton.
Listen and evaluate the intersection. Determine traffic patterns and the geometry of the intersection and listen for a pushbutton locator tone, or a tone or spoken Walk indication.
Remember the difference between a pushbutton locator tone and walk indication and listen to see what is there. Pushbutton locator tones are going to be repetitive, at once per second, like a grandfather clock - throughout the Flashing Don’t Walk and Don’t Walk. If there is a pushbutton for each crosswalk on the corner, you may hear two locator tones sounding. Sometimes the locator tones will be in sync with each other and sometimes out of sync. Check the tactile arrow to be sure a pushbutton controls the signal for the street you want to cross
Listen through a cycle to confirm the sounds and the street they apply to. Bear in mind that if the audible Walk indications seem to be available at every change of the light, you are probably at a “fixed time” location, and a button press will not be necessary. However, sometimes you still have to push a pushbutton for the major street crossing, even when audible indications sound every cycle for the minor street crossing.
When crossing any major roadway, whether you hear an APS or not, you should probably search for a pushbutton. As is noted in Modern Intersections chapter the pushbutton can have a significant effect on the amount of time available to cross a street. (Use a systematic search pattern to maintain orientation. It’s easy to get turned around and end up facing the wrong street, if you don’t pay close attention at this point.
Because dog guides are trained to avoid obstacles, they may be reluctant to approach poles that support pedestrian pushbuttons. It may be more efficient for the handler to use a cane to search initially before teaching the dog to locate the pole.
Once the APS is located, explore the device and its functioning. Locate the tactile arrow and confirm that the arrow is pointing in the direction of the street that you intended to cross.
The arrows should be, but are not always, aligned with the direction of travel on the crosswalk, and so might provide another cue for alignment. You may be able to align the outside of your arm with the pushbutton and flat face of the APS to help with the direction to cross.
Hold the pushbutton down for one to three seconds to see if more information is provided (see info on pushbutton information messages and audible beaconing under Other Features in this chapter).
Listen to the APS and traffic for a full cycle to make sure that the tones or speech walk indication corresponds to the traffic information.
Press the pushbutton when the perpendicular traffic starts to move in order to allow time for you to return to your predetermined spot at the curb, realign, and prepare to cross. Be ready to cross.
When you hear the Walk indication, (On Your Mark!) confirm that traffic on the perpendicular street is stopping or stopped, and listen for initial parallel traffic movements, if available (Get Set!).
Cross the street (Go!), using typical alignment techniques (paying attention to traffic, maintaining a straight line of travel, and so forth) and continue to listen for turning cars. In many cases, cars can turn right and left across the crosswalk during the pedestrian phase. Although drivers are supposed to yield to pedestrians, they often do not.
The pushbutton locator tone on the destination curb may be audible as you approach the last lane of the street, but may not be audible from the middle of the street.
Information on Accessible Pedestrian Signals can be found at www.apsguide.org.
Accessible Countdown Sidebar
To clarify the information, an orange countdown indicating remaining time available for crossing is displayed next to the Flashing Don’t Walk, or flashing orange hand. When the steady Don’t Walk or solid Orange Hand is displayed (which usually corresponds to the yellow light for vehicles), the countdown should be at zero. Studies have shown that this countdown has made the symbol of the Walking Man, followed by the Flashing Orange Hand (pedestrian clearance interval) clearer to sighted pedestrians, and resulted in pedestrians completing their crossings before the signal changed.
There is no consensus at this time within the blind and visually impaired community as to the extent of information that is to be provided by an accessible pedestrian countdown signal and whether it should count down the seconds available in the flashing don’t walk interval for completing the crossing.
Some advocates believe that only during the WALK interval is there a need to be provided an auditory announcement that they can leave the curb and enter the intersection. Further these individuals feel that having access to the countdown information is not as important to them, because of the possible negative effect on their ability to hear cars.
On the other hand, there are advocates who believe that all information presented visually must be matched by audible information and that the speech countdown can be used for directional guidance through an intersection. These individuals feel that from the standpoint of equal access they have the right to all the same information that is made available to persons who are sighted, such as the length of time remaining during the pedestrian clearance interval. They feel that hearing the countdown enables persons who are visually impaired to know exactly what pace they should maintain or adjust instead of having to speed up at the very end when surprised by the ending of the cycle. Further, they feel that the auditory countdown provides directional guidance assistance through an intersection for persons who are visually impaired.
While the authors are generally sympathetic to the viewpoint of those who want the countdown to be provided in audible format, we disagree for several reasons:
1. The speech message of the audible countdown might be mistaken for the Walk signal by persons who approach during the flashing Don’t Walk interval, leading them to begin crossing during the flashing Don’t Walk.
2. Pedestrians who are blind generally want to be able to hear traffic while crossing the street. The audible message could distract them from hearing traffic, particularly quiet vehicles. For the countdown to be equivalent it must be audible for the length of the crossing, just as it is visible for the length of the crossing. For this to happen it would need to be quite loud, blocking traffic noise as well as interfering with the traveler’s ability to concentrate and correctly interpret the distance, direction, and the rate of approach of vehicles while in the street.
3. Pedestrians who have vision impairments, without access to the accompanying visual orange hand, signifying “wait”, have been reported to assume that the countdown was counting down the time until the beginning of the walk interval, resulting in their beginning to cross just as conflicting traffic commenced.
4. Additional cognitive processing may be required to interpret a verbal message, such as an audible countdown.
5. Pedestrians with visual impairments are not usually able to precisely judge the width of streets to be crossed unless they have previously crossed them. While crossing the street, they may not know how much further they have to go to reach the curb, so the countdown may not provide information that is usable or advantageous. If the countdown says 4, do you know how far you can walk in that time? Before crossing, pedestrians who are unfamiliar with a particular crossing may hear, for example, 20 (seconds) and assume that is plenty of time to cross even what sounds like a major street. However, if that street has eight travel lanes, the pedestrian traveling at 3.5 feet per second will not have time to reach the far side of the street before the end of the flashing don’t walk interval.
6. It has been documented that providing a louder locator tone during the flashing don’t walk, from the accessible pedestrian signal on the opposite end of the crosswalk, improves accuracy for pedestrians who are blind in completing crossings within the crosswalk. (Scott, Barlow, Bentzen, Bond, and Grubbe, 2008). It is unlikely that countdown messages at an elevated volume will work as well, because speech is not as localizable as a percussive tone, nor as detectable and intelligible in traffic sounds. This louder locator tone is provided in response to an extended button press, so it has the potential of disturbing surrounding people only on the occasions when it is actuated by pedestrians who desire directional guidance.
For all of these reasons, at least until there is further research on the subject of audible countdown indications, the authors believe that APS sounds should be restricted to:
a) an audible equivalent to the visual WALK display, signifying the beginning of the pedestrian phase,
b) pushbutton locator tones, providing information about the location of the pushbuttons, possibly with options for boosting the volume to provide directional information, and
c) pushbutton information messages, which provide information about the street names, and special signalization or geometric situations.
It may be possible to add some information about the time available to either the pushbutton information message or to the audible equivalent to the WALK, but no research has yet been done to determine the best way to accomplish this. There are concerns about how to accomplish this technically, because the time available may change, in the computer-controlled world of traffic signals, and the audible messages are not currently immediately changeable.
Be sure to read the Modern intersections chapter so you have a better knowledge of what’s going on at the intersection.
Accessible Pedestrian Signals: A Guide to Best Practice, www.apsguide.org.
Barlow, J.M., and Franck, L. (2005) “Crossroads: Modern interactive intersections and Accessible Pedestrian Signals”. Journal of Visual Impairment and Blindness. Vol. 99, (10), 599-610.)
Scott, A.C., Barlow, J. M., Bentzen, B.L., Bond, T.L.Y. and Grubbe, D. (2008) Accessible Pedestrian Signals at complex intersections: Effects on blind pedestrians. Transportation Research Record: Journal of the Transportation Research Board, No. 2073, 94–103.