When and how often the APS installation should be checked

As with any complex device, an APS has many features that could malfunction or fail in the course of its operation. If features such as WALK indication, locator tone, or signal interaction fail to work correctly, the resulting lack of information or misinformation for pedestrians who are blind can be dangerous. It is important that municipalities who have taken steps to install these devices also take steps to ensure correct functioning through the years.

The overseeing agency should conduct an audit or checkup of the APS installations on a regular basis. Checkups should be conducted frequently if factors such as harsh weather may have affected the devices. At the very least, the APS should be checked:

What should be checked

On each regular visit to conduct a checkup of the APS units, the evaluator should recheck each of the items on the original post-installation checklist (see previous section). To add more specific items to the list, the following list comprises some of the most common failures that have been observed on installed APS devices. These items should be checked specifically, since some may not be obvious on a cursory glance:

Other operation and maintenance issues

Repairing an APS after a crash

Figure 7-13. APS was temporarily replaced on the pole, but the tactile arrow points to the center of the intersection, rather than being aligned with the direction of travel on the crosswalk.

It is essential that all maintenance personnel understand the functioning of the APS and consider it during repairs.

One municipality had a problem when the pole of the APS was knocked down in an accident and the repair team replaced the pole with the APS oriented toward the wrong street (see Figure 7-13). The speech message and arrow did not match up; the speech was saying "WALK sign is on to cross Harford Road" (at the correct time) but the arrow on that device pointed toward Taylor Avenue.

In another instance, an APS was damaged by a car that left the roadway. The APS was just strapped back onto the pole with no attention to the alignment of the tactile arrow. The APS continued to function, but was pointing to the center of the intersection, rather than being aligned with the appropriate crosswalk.

Lessons Learned from APS Installations

New technology

Not unlike any new technology, the first installation of new types of APS devices does not always operate flawlessly. There are issues to resolve with some of the devices. In addition, reports from older installations have brought up recurring problems that need to be addressed in installation. All of the issues were easily solvable. The following should provide information to prevent these problems from reoccurring. Some issues include:


Some minor problems have been experienced with wiring and color code.

Other problems may be related to incorrect wiring of the pushbutton units:

Pushbutton installation and vibrotactile indication

Figure 7-14. Incorrect installation of two APS on a single pole (no vibratory insulation)

When two APS pushbuttons with vibrotactile indications are installed on the same pole, they may require insulation and a rubber gasket to eliminate vibrations generated from the other pushbutton.

A problem was experienced when two pushbuttons were on the same pole with no vibratory insulation (Figure 7-14). Pedestrians were unable to determine which pushbutton was vibrating, since it appeared both were. Proper insulation of the pushbutton will prevent this problem from occurring.


Volume adjustment

Although current standards call for the APS volume to only be 2 to 5 dB above ambient sound and for the locator tone to be heard from 6 to 12 feet from the pushbutton, volume is often set much louder than that.

One installation experienced a different problem in adjusting the volume of an APS unit.

Speech messages

The speech messages used for the WALK indication, as well as the descriptive pushbutton message, must be understandable.

Pushbutton and pole location

Some problems have been observed in locations of pushbuttons and poles of APS devices:

Tactile arrow and position

The tactile arrow is supposed to point in the direction of pedestrian travel on the crosswalk and the face of the device is supposed to be parallel to the crosswalk it controls.

Some installation issues:

Speaker positioning

Figure 7-15. APS pushbuttons installed incorrectly

Figure 7-16. APS pushbuttons installed correctly

Pedestrian head mounted speakers in existing installations are often mounted in positions that make the messages more ambiguous. See examples in Chapter 6 in "APS Microphones and Speakers" and also earlier in this chapter.

For pushbutton integrated devices, the speaker is in the pushbutton housing. Location of the pushbutton and orientation of the speaker can be critical to hearing the WALK indication at the crosswalk. If the speaker is located too far from the crosswalk location, pedestrians who are blind may not hear the WALK indication.

As shown in Figure 7-15, the pushbuttons are installed incorrectly, so the APS is too far from the crosswalk it signals and the sound for the other crosswalk at the intersection comes from a speaker that is closer to the crosswalk.

In Figure 7-16, the APS are installed correctly (close to the crosswalk they signal) and provide accurate information through proximity to the crosswalk.

Braille signing and location

Braille indications on the pedestrian signals have sometimes been mounted backwards or with the braille label for the wrong street.

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