Accessible Pedestrian Signals: A Guide to Best Practices (Workshop Edition 2010) (2011) / Chapter Skim
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From page 93... ...
Accessible Pedestrian Signals: A Guide to Best Practice 93 Chapter 6: Designing APS Installations CHAPTER SUMMARY Accessible Pedestrian Signal installations require engineering, including detailed drawings and specifi cations. Complex intersections require complex decisions and the use of engineering judgment.
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From page 94... ...
94 Chapter 6: Designing APS Installations Principles GENERAL PRINCIPLES IN THE DECISION: • Provide pedestrian signal information to those who cannot see the pedestrian signal head across the street • Provide information to pedestrians about the presence and location of pushbuttons, if pressing a button is required to actuate pedestrian timing • Provide unambiguous information about the WALK indication and which crossing is being signaled • Use audible beaconing only where necessary o Put as little additional sound in the environment as possible o Avoid disturbance of neighbors o Allow pedestrians who are blind or visually impaired to hear the traffi c sounds, as well as the APS FEATURES In many cases, a municipality or state will wish to purchase one style of APS device for all installations. However, there are engineering and design decisions in the installation of APS, as well as in the choice of equipment.
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From page 95... ...
Accessible Pedestrian Signals: A Guide to Best Practice 95 Whenever possible, two poles should be installed for APS speakers to be located close to the pedestrian departure location and crosswalk, as described in detail below. Recommendations about location and WALK indication have been updated as a result of recent research (see Appendix C for research results)
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From page 96... ...
96 Chapter 6: Designing APS Installations When pushbuttons are precisely and consistently located in this way, identifi cation of which crossing is being signaled can be based solely on which pushbutton the WALK signal comes from. Th ere is no need to remember a code (such as cuckoo for a north/south crossing and rapid tick for an east/west crossing)
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From page 97... ...
Accessible Pedestrian Signals: A Guide to Best Practice 97 APS INSTALLATION WHERE TWO SEPARATED POLES ARE NOT POSSIBLE Where the only work being done is the addition of APS to existing poles, or where it is technically infeasible, because of limited right-of-way, topography, or locations of other essential equipment on corners, to install two APS on separate poles on the corner, it may be necessary to install two APS on a single pole. However, the APS features required for this situation are diff erent from those where APS and APS sounds are separated.
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From page 98... ...
98 Chapter 6: Designing APS Installations Signal Phasing Considerations INTRODUCTION Some signalization schemes, such as exclusive pedestrian phasing and split phasing, need careful adjustment and consideration to avoid confusing pedestrians who are blind. Crossings with pedestrian signals that rest-in-WALK may need special treatment.
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From page 99... ...
Accessible Pedestrian Signals: A Guide to Best Practice 99 • An APS with speakers mounted at the pushbutton, or pedestrian signal head, with carefully set volume and very careful placement and adjustment, to be heard only at the crossing location (see photos and discussion in Chapter 7)
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From page 100... ...
100 Chapter 6: Designing APS Installations WALK indication. Th is is not recommended, as it is confusing to all pedestrians, and pedestrians who are blind typically assume that the signals are broken.
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From page 101... ...
Accessible Pedestrian Signals: A Guide to Best Practice 101 Benefi ts of pushbutton-integrated APS in a downtown area Engineers may wonder why they should install a pushbutton-integrated APS if pushing the button has no eff ect on a pretimed signal. Th e key is to realize that pushbutton-integrated APS have several features that are benefi cial to blind pedestrians, even if there is not a need to push the button: • Audible WALK indication -- same as for any intersection, the audible WALK indication will let the blind pedestrian know that the walk interval has started so that they will not have to rely solely on traffi c noise.
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From page 102... ...
102 Chapter 6: Designing APS Installations might be considered to meet them to the maximum extent feasible, when existing conditions and structures prevent installation of additional poles to mount the APS beside the crosswalk. When an APS is mounted on pedestrian signal heads, the WALK message or tone and volume levels should be carefully determined to avoid confusion to pedestrians, and to prevent disturbance to neighbors.
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From page 103... ...
Accessible Pedestrian Signals: A Guide to Best Practice 103 Intersection Geometry Considerations EFFECT ON APS An APS that is audible from the wrong crossing location may lead a visually impaired pedestrian to begin to cross at the incorrect time and place. Geometric features, such as unsignalized and signalized right turn lanes, have been recognized as situations of concern in language in the MUTCD.
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From page 104... ...
104 Chapter 6: Designing APS Installations SIGNALIZED CHANNELIZED RIGHT TURN LANES Where crosswalks from corners to splitter islands are signalized, the signals to cross to the island might not be concurrent with traffi c movement parallel to the pedestrian who is blind, depending on the crossing location. APS should be located precisely next to the associated crosswalks with careful volume adjustment.
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From page 105... ...
Accessible Pedestrian Signals: A Guide to Best Practice 105 APS Design in New Construction DRAFT PROWAG Revised Draft Public Rights-of-Way Accessibility Guidelines (Draft PROWAG) were released on November 23, 2005.
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From page 106... ...
106 Chapter 6: Designing APS Installations • With control face of the device installed facing the intersection, parallel to the direction of the crosswalk it serves. • Clear fl oor or ground space at the pushbutton shall connect to or overlap the pedestrian access route.
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From page 107... ...
Accessible Pedestrian Signals: A Guide to Best Practice 107 Figure 6-8. Ideal placement for pushbuttonintegrated APS Figure 6-9.
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From page 108... ...
108 Chapter 6: Designing APS Installations Figure 6-10. The APS should be located on the intersection side of the pole, as shown in this photo Figure 6-11.
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From page 109... ...
Accessible Pedestrian Signals: A Guide to Best Practice 109 APS Design at an Existing Intersection APPLICATION OF NEW CONSTRUCTION GUIDELINES In retrofi t situations, the ADA requires that new construction guidelines be followed to the maximum extent feasible, if compliance with the new construction guidelines is technically infeasible. Th e determination of technical infeasibility will vary depending on the scope of the project and the existing situation.
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From page 110... ...
110 Chapter 6: Designing APS Installations Needs Assessment STRATEGIES After an engineering study determines that APS should be installed at an existing signal, strategies for integrating the APS into the sidewalk environment need to address certain issues and/or questions. Th ose in charge of installing APS at an intersection must conduct a needs assessment to determine which features are suitable in order to develop detailed installation plans.
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From page 111... ...
Accessible Pedestrian Signals: A Guide to Best Practice 111 INTERSECTION GEOMETRY AND NEED FOR AUDIBLE BEACONING Audible beaconing is not needed at many intersections, although APS in the United States have traditionally been installed with beaconing. Questions to consider: • Is audible beaconing needed at the intersection?
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From page 112... ...
112 Chapter 6: Designing APS Installations Pole Location EXISTING POLE LOCATION When the only change is addition of APS at an intersection (usually in response to a request) , the existing pole location at the intersection often restricts the location of the APS components (such as pushbuttons, speakers, and tactile arrows)
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From page 113... ...
Accessible Pedestrian Signals: A Guide to Best Practice 113 1. Repositioning of pedestrian signals and poles, or the addition of stub pole(s)
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114 Chapter 6: Designing APS Installations 2. INSTALLING TWO APS ON ONE POLE Many jurisdictions use a standard design of two pedestrian signal heads and pushbuttons on one pole.
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From page 115... ...
Accessible Pedestrian Signals: A Guide to Best Practice 115 Specifi cations When ordering APS units from the manufacturer, practitioners will need to be specifi c concerning the features and settings that they desire or require. Th e level of detail required by the manufacturer varies depending on the company.
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From page 116... ...
116 Chapter 6: Designing APS Installations It is also useful to include an intersection diagram showing: • crosswalks to be controlled • pushbutton locations • speaker locations and angle (if pedhead-mounted speakers are desired)
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From page 117... ...
Accessible Pedestrian Signals: A Guide to Best Practice 117 Mounting and Wiring Issues LOCATION OF CONTROLLER BOARDS AND WIRING Wiring Pushbutton-integrated APS may require an extra set of wires to the pushbutton to power the audible indications. APS with actuation indicators may need to receive an actual signal from the controller that the call has been accepted.
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From page 118... ...
118 Chapter 6: Designing APS Installations • Manufacturers may be able to supply a separate case for the APS control board (see Figure 6-19)
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From page 119... ...
Accessible Pedestrian Signals: A Guide to Best Practice 119 ordering the units. Th e pole location in relation to the crosswalk can aff ect the direction of the arrow.
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From page 120... ...
120 Chapter 6: Designing APS Installations Figure 6-25. This APS is mounted on a wooden pole by drilling a hole through the pole and running wires through the back of the device Figure 6-26.
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From page 121... ...
Accessible Pedestrian Signals: A Guide to Best Practice 121 Figure 6-31. Stub pole example Figure 6-32.
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From page 122... ...
122 Chapter 6: Designing APS Installations APS Microphones and Speakers MICROPHONE LOCATION Some APS require installation of microphones to monitor the ambient sound; this is part of the automatic sound adjustment feature. Th e microphones measure the sound levels to adjust the volume at the waiting location.
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From page 123... ...
Accessible Pedestrian Signals: A Guide to Best Practice 123 H-frame for pushbuttons An H-frame is used for mounting pushbuttons in some northwestern states. Some APS devices will not work properly when mounted in this confi guration.
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From page 124... ...
124 Chapter 6: Designing APS Installations Figure 6-38. Acceptable placement for pushbuttonintegrated APS Figure 6-39.
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From page 125... ...
Accessible Pedestrian Signals: A Guide to Best Practice 125 Figure 6-40. Acceptable placement for pushbuttonintegrated APS, only when installing in a retrofi t situation on an existing pole (if APS cannot be separated, there will need to be a speech pushbutton information message and WALK message to prevent ambiguity)
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From page 126... ...
126 Chapter 6: Designing APS Installations PEDHEAD-MOUNTED SPEAKERS Sound from pedhead-mounted speakers Th e sound from pedhead-mounted speakers is not very useful for providing guidance about the location of the opposite curb. Unless audible beaconing is required, speakers should be aimed down toward the pedestrian waiting location.
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From page 127... ...
Accessible Pedestrian Signals: A Guide to Best Practice 127 Speaker location While the direction of the speaker does make a diff erence, it is common for overhead speakers that are attached to pedheads to provide ambiguous information. Figure 6-44 illustrates such a speaker and pedhead placement.
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From page 128... ...
128 Chapter 6: Designing APS Installations Figure 6-46. Recommended placement for pedheadmounted speakers where beaconing is needed Figure 6-47.
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From page 129... ...
Accessible Pedestrian Signals: A Guide to Best Practice 129 Figure 6-48. Possibly acceptable placement for pedhead-mounted APS using mast arms to provide additional separation Figure 6-49.
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From page 130... ...
130 Chapter 6: Designing APS Installations Figure 6-50. These APS speaker placements are unacceptable, regardless of how speakers are aimed Figure 6-51.
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From page 131... ...
Accessible Pedestrian Signals: A Guide to Best Practice 131 Summary of Recommended Features and Installation Practice APS INSTALLATION IN NEW CONSTRUCTION Recommended features • Rapid tick WALK indication, no more than 2-5dBA above ambient sound • Vibrotactile WALK indication • Speaker and vibrotactile indication located at pushbutton • Pushbutton locator tone • Tactile arrow on each device aligned in direction of travel on the crosswalk • Braille or audible street name Recommended installation • Precise location of the APS is very important to prevent ambiguity about which crosswalk is being signaled • APS should be reachable from the level landing of the curb ramp for the crossing or from a level surface with an accessible path to the ramp • APS should be within 5 feet of the extension of the crosswalk lines and within 10 feet of the curb • Tactile arrow should be aligned with the direction of travel on the crosswalk • Face of the device oriented toward the intersection (APS should be located on the intersection side of the pole) • Th e APS on the same corner should be a minimum of 3 m (10 ft)
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From page 132... ...
132 Chapter 6: Designing APS Installations CONFIGURATION-SPECIFIC RECOMMENDATIONS Below are listed some specifi c situations in which there are installation recommendations in addition to the ones listed above for new construction and existing construction. Th e recommendations listed for each situation below are only the areas where they diff er from the general recommendations listed above.
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From page 133... ...
Accessible Pedestrian Signals: A Guide to Best Practice 133 Figure 6-52. Example of pushbutton information messages and speech WALK messages for two APS located on the same pole
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From page 134... ...
134 Chapter 6: Designing APS Installations
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