Technological advancements also are making use of solar-powered CMSs and arrowboards more practical. Improvements in the manufacturing of photovoltaic cells--devices that generate voltage when exposed to radiant energy such as the sun--have resulted in lower cost of the cells, thus making solar power more affordable.
Another technological advance is high-intensity light-emitting diodes, commonly known as LEDs. LEDs have many advantages over traditional incandescent lamps. They operate on very low voltages, making them more energy efficient. They can be designed to emit a specific light color. Incandescent lamps emit only a white light. They also are very rugged and durable.
Changing social views concerning the environment and technological improve- ments have lead to increased uses of solar-powered arrow- boards and CMSs. Now that they are available, they are proving their worth over gasoline- or diesel-powered boards. Signs powered by fossil fuels use an engine and a generator to produce its power, thus requiring more manpower in refueling. With more moving parts and a reliance on consumable fuel, diesels have a greater potential for power failure. This results in more time spent fixing break-downs and performing maintenance. Breakdowns and fuel exhaustion will cause the sign to cease functioning, which leads to potential safety problems.
Depending on the model, solar- powered signs can last 18 to 30 days without sunlight. And overcast days are not a problem because enough ultraviolet rays and infrared radiation is coming through the cloud cover to power the signs. With only a periodic check of the battery banks required, less man-hours are spent maintaining the units.
The following is a partial listing of some available solar-powered sign boards.
Addco Manufacturing, St. Paul, Minn., offers two models of CMSs, the all LED DH1000 ALS and the LED-DOT sign. Both combine the technologies of LED, solar power and batteries to provide signs powered only by the sun. Each feature solar panels that rotate 340 deg and tilt from 0 to 40 deg to optimize the capture of the sun's rays. The ALS features enhanced legibility, reduced glare and increased contrast in the character display through the company's Eclipse system.
The LED-DOT sign comes with a fluorescent flip-disk technology for use in the daytime, and the LED technology for nighttime or low-light use. The company claims that this sign uses 50% less electrical power than a conventional flip-disk diesel- powered sign.
Addco also offers a portable traffic light signal powered by solar energy. The system consists of two signal trailers, which constantly communicate with each other via a two-watt radio link. They are designed for one-person set-up in less than 20 minutes and offer an alternative to flaggers and pole signals.
Makers of Eclipse--solar-powered flashing arrowboards--Allmand Brothers Inc., Holdrege, Neb., has modified its product by incorporating the use of LED lamps. Halogen lamps also are available. This improves the unit's energy efficiency. The Eclipse uses two, three or four self-regulating solar panels to charge commercial marine deep-cycle power batteries. The panels are available in either 50-, 75- or 100-watts and optional panels may be added to increase the charging of the batteries. When the arrowboard is in a stowed position for travel or storage, the panels remain facing upward to collect energy and charge the batteries.
Fully charged, it can run unattended for weeks. A bright red flashing low-voltage warning light indicates when the batteries need recharging, and is visible for drive-by inspections. An on-board circuit monitor insures optimum battery life by shutting down the unit before the voltage drops to a battery-damaging level.
The company also offers a retrofit kit, which can be used to convert a gasoline or diesel-powered board into a solar-powered one.
Models available include the 2200/SE ALT, 15-lamp Eclipse and the 2200/SE APF 25-lamp Eclipse. Both come with either LED or halogen lamps.
American Electronic Sign
The company has recently introduced a smaller solar-powered LED-hybrid CMS called the Trilux-1 Junior PCMS. It is closer in size to an arrowboard than a full-sized CMS, but will still display three lines of text with eight characters per line. The company claims the smaller size makes it ideal for cities and counties that do not have the wide shoulders typically found on the interstate highways. The full-matrix sign allows various character heights from 10.5 in. to 36 in. and traffic safety symbols to be displayed.
The display utilizes amber Indium -based LEDs for illumination in combination with a retroreflective pixel sheeting material. The sheeting helps to broaden the viewing angle and provides a display that will not fade in color intensity. This also provides a programmable default message that is visible in daytime or nighttime.
The product features a programmable touchpad controller that allows the user to scroll through a list of preprogrammed text messages and symbols. It also comes with an optional radar device that will display a passing car's speed along with a safety message. The radar software will log information such as the number of cars that passed, mean speed, maximum speed and minimum speed.
American Signal Co.
This company offers the CMS-GP432 general purpose CMS. It features an all LED full-matrix display and can be charged with either solar power or diesel power. The solar system has a battery life of 30 days. Graphic options for the display include 27 MUTCD symbol signs, nine character fonts featuring character heights from 9 in. to 28 in. There are 199 pre-programmed messages and 199 user-defined messages, as well as full-height chevrons or moving arrows. The product also has the ability to flash lines or the entire message. Optional features include remote control via a cell phone, a pick-up truck-bed-mount sign support system including adjustable sign height and rotation, and radar activated message interrupt and on-line sign-speed display.
Also available is the CMS-T321 Hybrid portable CMS, which employs amber LED and Flip Dot display technologies. Like their other product this can be powered by either solar or diesel, and has a solar-charged battery life of 30 days. Other options include cell phone remote control and radar activation.
Display Solutions offers three models of CMSs, the Sunray 340, 345 and 380. All models feature a default warning indication if the batteries become discharged, an electro-hydraulic raise/lower mechanism, a single-board processing unit to simplify trouble shooting and repair, moving arrows and chevrons and over 200 pre-stored messages.
The company also offers the Sunray Hybrid, an LED CMS with flip disks. This product has many of the same features as the other three.
They also make a solar-powered arrowboard with a 90-watt solar panel mounted above the sign case. The panel can be tilted 90 deg to optimize charging. Its batteries provide 30 days of single arrow operation without recharging. The 98-in.-wide x 48-in.- high sign panel uses LED lamps, which are visible at 17 deg from one mile.
Precision Solar Controls
Their Solar Message Center is a portable, CMS, which uses LED lamps and solar panels. It is capable of operating independently of the sun for 30 days with 2.5 hours of good sun required for each additional day of operation.
The company also offers its Solar Mobile Traffic Monitor for use by police departments to promote speed limit compliance. As motorists approach the unit their speed is displayed on the screen. It is trailer mounted and incorporates LED technology in its 20-in. character display. The monitor also has the capability of gathering and classifying pertinent vehicle data. The solar panel array is sized to provide one day's system power supply in just two to three hours of good sun. The battery bank is sized to provide 18 days of continuous operation with no sun.
The company's solar-powered Arrowmaster is an arrowboard, which can operate for 30 days without the sun. Whether in an operating or a travel position, the solar panel is positioned for maximum charging capabilities.