Case Study — Montgomery County, Maryland

Date: May 2003

History and background

The intersection of Fenton Street and Wayne Avenue is the first of eleven locations in the Silver Spring Central Business District (CBD) to be equipped with APS under a pilot program initiated by the County Executive.

Process and procedure

There is no formal procedure to request APS. A committee was formed, in coordination with the Montgomery County Commission on Persons with Disabilities, to make decisions about type and features of APS to be installed.

Most signalized intersections in the county are on state roads, so final decisions of the State Highway Administration on APS policy will affect installation at those locations.


Costs for the pilot project are absorbed as part of the traffic engineering department budget. An additional line item for APS installation was requested in budget but was not funded.

Description of intersection

These traffic signals are being rebuilt as part of the redevelopment of the CBD. Fenton Street and Wayne Avenue was the first one to be rebuilt, and hence the first to receive APS. All intersection legs are 4 lanes wide. Fenton Street runs approximately north/south and Wayne Avenue runs east/west. There is a leading left turn phase from westbound Wayne to Southbound Fenton.

Date installed

September 2001

APS type and features

Pushbutton-integrated devices from Polara Engineering.

Intersection is pre-timed, with WALK intervals associated with each crossing being provided each cycle, but the APS are actuated (audible and vibrotactile WALK indications are not provided unless the pushbutton is pushed).

APS features:

APS installation

Figure 9-1. Pushbutton-integrated APS located on a stub pole beside the level landing of the curb ramp

Figure 9-1. Pushbutton-integrated APS located on a stub pole beside the level landing of the curb ramp

Figure 9-2. Pedestrian with dog guide at an APS located in line with crosswalk.

Figure 9-2. Pedestrian with dog guide at an APS located in line with crosswalk.

Devices are installed on all four corners, using stub poles for all in order to place the pushbuttons and APS at the top of the ramp for each direction, separated by at least 10 feet.

Each pole is approximately five feet tall with a substantial base; locations vary somewhat but are generally:

The Polara control unit and the microphone, which monitors sound for the automatic volume adjustment, are typically installed inside 18-inch pedestrian traffic signal heads. At this location with 12-inch pedestrian signal heads, the control units were installed in an exterior box attached to the top of the pedestrian traffic signal heads. The microphone was attached to the box, which located it much higher than usual; however, that placement seems acceptable.

Installation issues

There were no real problems with the installation. However, locating the poles and APS properly in relation to the curb ramp and as recommended in the MUTCD is difficult. While it may be less of a problem in new construction, it requires thought and planning, as well as extra poles, conduit, wiring and construction in retrofit situations.


Except for some minor adjustments after installation, there have been no maintenance issues or failures.


No formal evaluation has been conducted. Committee members visited the installation and were generally pleased with the functioning.


Bruce Mangum, Senior Engineer
Transportation Systems Management Section
Division of Public Works and Transportation
Montgomery County Maryland
101 Monroe Street, 11th Floor
Rockville, MD 20850
Phone; 240-777-8778 — Fax: 240-777-8750

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