Case Study — Charlotte, North Carolina

Date: July 2003

History and background

Charlotte began installing pushbutton-integrated APS in 1999 after discussion with the Charlotte/Mecklenburg Advocacy Council of People with Disabilities Committee. Approximately twelve intersections with forty-two pushbutton-integrated APS devices are now installed. Before that, pedhead-mounted APS had been installed upon request; current staff are not sure when those devices were installed or how the decision was made to install them. They state that they are replacing current "chirpers" with pushbutton-integrated devices.

Orientation and Mobility specialists helped evaluate APS products in advance and made recommendations to engineers.

Process and procedure

APS are requested by citizens and installed after review by staff of Metrolina Association for the Blind. In general, devices are installed in the order of request, depending on how much construction is involved.

The Charlotte/Mecklenburg Advocacy Council for People with Disabilities Committee and the Metrolina Association for the Blind serve as liaisons between the person who is visually impaired and the city.


City council approved $95,000 in a restricted fund that is carried over year to year for purchase of equipment. The installation cost is covered in the normal budget. The public and individuals who are blind were involved in making the request for funding and getting it approved.

APS type and features

Pedhead-mounted devices before 1999

Pushbutton-integrated devices from Polara Engineering since July 1999

APS features (pushbutton-integrated device installations):

Installation issues

Figure 9-18. Recent Polara Navigator installation.

Figure 9-18. Recent Polara Navigator installation.

The first generation Polara device did not accommodate pre-timed or "ped recall" locations. It was designed to look for a logic common signal from the controller. Using instructions provided by Polara, city technicians in the signal shop modified the printed circuit board, including adding a resistor and two jumpers. This being done, the devices were usable in these situations.

A simple jumper setting has addressed this problem with the newer Polara product. The first generation Polara (installed at four locations) was also more labor intensive to install. Installers drilled holes in the top of the device to accept conduit on wood pole locations.

The newer version Polara Navigator has addressed all installation concerns.

When it is necessary to install new poles to locate the device more appropriately, it takes longer and more funds, because traffic engineering has to coordinate with various departments to fix curb ramps and work around other utilities. Installation can be time-consuming when a new pole is needed.


No problems reported

In early installation where two devices were on the same metal pole, it was possible to feel the vibration during WALK on both devices at the same time (separate WALK phases). This was solved by insulating between the device and pole. A speaker problem was resolved by improving the installation method through efforts between the City Electronics Tech and the manufacturer.


The Public Service Department has no complaints regarding the devices. However, staff of Metrolina Association for the Blind received some complaints about the noise level of the locator tones, especially in residential areas. The volume can easily be adjusted.

The City of Charlotte placed in the top ten U.S. cities in the Accessible America contest a year ago and in the top seven this past year. Metrolina Association for the Blind has provided very favorable input and review of this project. Communication between all agencies involved has made this project a success.


Tamara (Tammy) Drozd, Signal System Specialist
City of Charlotte NC
600 East Fourth Street, Charlotte, NC, 28202-2858
Phone: 704-336-4385
Fax: 704-336-4400

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