Optimal APS Location
The optimal location for pushbutton-integrated APS is between the edge of the crosswalk line (extended) farthest from the center of the intersection and the side of the curb ramp. APS should be between 1.5 feet and 6 feet from the edge of the curb, shoulder, or pavement but no further than 10 feet from the edge of the curb, shoulder or pavement. The control face and tactile arrow should be carefully aligned with the direction of travel on the associated crosswalk. In order to provide wheelchair users with access to the pushbutton, pushbuttons need to be located adjacent to a level all-weather surface.
Figure 6-1. Optimal location of pushbutton-integrated APS (two pushbuttons on one corner, mounted on two separated poles " rapid tick WALK indication)
Pushbutton and speakers for the APS need to be less than 5 feet from the edge of the crosswalk line (extended) farthest from the center of the intersection. At corners of signalized locations where two pedestrian pushbuttons are provided, the pushbuttons should be separated by a distance of at least 10 feet (see Figure 6-1). A rapid tick WALK indication is required (MUTCD Section 4E.11, P7) for installations following these guidelines for location.
When pushbuttons are precisely and consistently located in this way, identification of which crossing is being signaled can be based solely on which pushbutton the WALK signal comes from. There is no need to remember a code (such as cuckoo for a north/south crossing and rapid tick for an east/west crossing) or to understand speech messages. Figure 6-2 provides examples of pole arrangements that meet the requirements for corners having different geometries. Figure 6-3 demonstrates acceptable APS placement at a corner with an improper ramp design.
Legend
10 ft radius, 5 ft sidewalk, parallel ramps
10 ft radius, 5 ft sidewalk with parkway, perpendicular ramps
30 ft radius, 12 ft sidewalk, perpendicular ramps
30 ft radius, 12 ft sidewalk, perpendicular ramps
30 ft radius, 12 ft sidewalk, parallel ramps
30 ft radius, 5 ft sidewalk, parallel ramps
30 ft radius, 5 ft sidewalk with parkway, perpendicular ramps
30 ft radius, 5 ft sidewalk with parkway, perpendicular ramps
30 ft radius, 5 ft sidewalk, single ramp, APS poles separated by 10 ft
20 ft radius, 5 ft sidewalk, single ramp, APS on single pole with speech messages
Right-angle right-of-way, 8 ft sidewalk, perpendicular ramps
Figure 6-2. Examples of locations for APS on corners with various geometries
Figure 6-3. Acceptable APS placement at location but inaccessible ramp design (no level space for passage through the sidewalk)
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 different from those where APS and APS sounds are separated.
When it is necessary to mount two pushbuttons on one pole without a separation of 10 feet or more:
- speech WALK messages are required rather than tones (MUTCD Section 4E.11, P7)
- pushbutton information messages identifying the intersection and the street to be crossed are needed to be sure users know the street name to listen for in the WALK message (MUTCD Section 4E.10, P3)
Research in Portland demonstrated that the participants' identification of which crosswalk had the WALK signal was significantly more accurate when the APS provided speech WALK signals from both APS than when the APS used two tones — cuckoo and rapid tick (see Appendix C).
Need for audible beaconing
Audible beaconing is the use of an audible signal in such a way that blind pedestrians can home in on the signal from the opposite corner to aid in alignment during the crossing. The need for audible beaconing may affect the type of device to be installed and the installation location. Not all manufacturers' devices are capable of providing audible beaconing. The need for beaconing should be evaluated and considered early in the design of the installation. A minority of crossings is likely to require beaconing and not all crosswalks at an intersection may need beaconing. Beaconing may actually cause confusion if used at some locations. See Chapter 4 for suggested criteria for audible beaconing.
[ back to top ]