Specifications include, but are not limited to: Install and operate digital messaging signs on the Parks Highway MP 357 and Richardson Highway MP 359.; DMS Sign Housing. The DMS housing structural frame shall consist of aluminum extrusions made from 6061-T6 and/or 6063-T6 aluminum alloy. All sides of the DMS housing exterior, except the front, shall be covered with 0.125-inch (3.17 mm) thick aluminum sheets made from 5052-H32 aluminum alloy. This external aluminum skin shall be attached to the structural framework using a proven method of attachment.; DMS housing right, left, and rear walls shall be vertical. The top and bottom sides shall be horizontal. The front DMS wall shall be built with a permanent forward tilt angle of three (3) degrees, so that the top of the DMS housing is deeper than its bottom. LED display modules shall be mounted parallel to the front wall, so they are tilted three (3) degrees forward toward the viewing motorists and use of the legible LED viewing area is optimized.; DMS structural assembly hardware (nuts, bolts, washers, and direct tension indicators) shall be galvanized A325 high-strength steel and shall be appropriately sized for the application.; Interior Work Area. Minimum headroom of 72-inches (1,829mm) shall be provided. This free space shall be maintained across the entire width of the DMS housing, with the exception of structural frame members. Structural members shall be designed not to obstruct the free movement of maintenance personnel throughout the DMS interior.; A level aluminum walkway shall be installed in the bottom of the DMS housing. The walkway shall be a minimum of 24-inches (610 mm) wide, and it shall run the entire length of the housing, from access door to access door. The walkway’s top surface shall be non-slip and shall be free of obstructions that could trip service personnel. The walkway shall support a load of 300 pounds (136 kg) per linear foot, and it shall be constructed of multiple aluminum removable panels.; Environmental Monitoring Systems. The DMS shall include sensors that monitor and report ambient (external) light level and temperature, as well as the internal temperature and humidity.; 8.1.Ambient Light Measurement Sensors that measure the outdoor ambient light level and the outdoor ambient temperature at the DMS site shall be mounted in-line with the DMS housing walls. This ambient light and temperature measurement system shall consist of three (3) electronic light sensors. Two of the light sensors shall be placed such that they measure the ambient light levels striking the front and rear of the DMS. The third light sensor shall be mounted to the floor of the DMS housing and shall face the ground. The DMS sign controller shall continuously monitor the light sensors and adjust the LED display matrix intensity to a level that creates a legible message on the DMS face.; 8.2.Ambient Temperature Measurement A minimum of one (1) ambient temperature sensor shall be mounted to the rear wall of the DMS housing. The sensor shall be placed such that it is never in direct contact with sunlight. The external temperature sensor reading shall be continuously monitored by the DMS sign controller and shall be reported to the DMS control software upon request.; 8.3. Internal Temperature Measurement and Heater. The DMS shall contain a minimum of one (1) temperature sensor and (1) heater. The temperature sensor(s) shall measure the temperature of the air in the cabinet over a minimum range of -40ºF to +176ºF (-40ºC to +80ºC). The internal temperature sensor output shall be continuously monitored by the DMS sign controller and shall be reported to the DMS control software upon request. The heater shall be thermostatically controlled with a set temperature of -10ºF.
