STC In The News

STC provides intersection ahead warning flasher in Pima County, AZ with TS2 Cabinet "Wireless" Control Interface

TEMPE, AZ - 04/04/2012 - Pima County surrounds the Tucson metro area. An intersection advance solar-powered flasher was installed at Ajo and Alvernon located on the south side of Tucson.

The intersection is located at the bottom of an overpass making it difficult for approaching motorists to see the signal. Coupled with the posted 45 mph speed limit on Alvemon - actual speeds are higher - you have a situation ripe for rear-end collisions. Static signs had been in place for years yet the county needed something more active.

Solar Traffic Controls was asked to propose an equipment package which would allow the flasher to run only when the lamp was in the red interval or whenever it was not green. Also to have a programmable time delay from the time when the selected logic trigger dropped; and to devise a way to put an alarm into the traffic control cabinet if the flasher lost radio communication with the traffic cabinet.

STC met the challenge by modifying its design of a Solar Ped-X wireless crosswalk slave for the flasher. To interface with the TS2 traffic cabinet at the site, STC revised its design of a Solar Ped-X master control panel so it ran from the nominal 120VAC supply in the cabinet and monitored the field wiring outputs for the logic. The interface control panel includes logic inputs which make it compatible with either TS1 or TS2 applications. In TS1 applications, load switch logic lines may be used to trigger the flasher.

All communication between the two units is done using FHSS radio and Yagi antennas. RF design was especially critical in this application since there are high voltage transmission lines adjacent to the site. Davis-Monthan Airfield is also adjacent to the site so radar and licensed high power communications are also present for interference.

In addition to the wireless link, solar power was a natural choice for the flashing beacon. This was due to the fact that the equipment was to be installed on an embankment where no power was available. It was impossible to bore a conduit under the roadway in this area as well.

The equipment was installed for the county by a JOC electrical contractor.

Celebrating our 11th year designing and manufacturing solar-powered traffic control systems. For more information on STC's products and services, please stay here on our website or send an email to info@solar-traffic-controls.com or call 480.449.0222.

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