For several years, communities throughout the country have been investing in backup power for traffic signals - and as a result have significantly improved safety, reduced accidents and injuries and cut costs related to controller maintenance and police intervention.

Today, battery backup systems (BBS) have evolved to accommodate a wide range of environmental challenges and customer needs. With increasing occurrences of extreme weather affecting utility power, proactive cities are investing to ensure their intersections are kept safe in extended power outage situations. Following are examples of two cities incorporating stationary DC generator solutions to provide extended runtimes.

City of Suffolk, VA
In 2002, in response to brownouts, sags and spikes causing damage to traffic controllers, the City of Suffolk began looking for ways to provide clean power to its intersections. At the time, traffic intersections used incandescent lighting, which meant the cost of providing a power backup solution was much higher than it is today.

The City began working with Jim Merritt, President of Critical Power Systems Inc., a certified power quality professional with over twenty-one years of critical power expertise. A large concern for the city was its geographic location being the one and only land exit for the Tidewater area. Using any other route meant traveling through a tunnel or across a bridge; a scary thought when anticipating what could happen in the event of a hurricane or other natural disaster.

This was an emergency evacuation route in need of a special solution. The recommendation: Alpha’s CFR UPS, which effectively corrected the problematic power. With independent systems installed at every major intersection between Suffolk and the Tidewater area, traffic could move smoothly regardless of the power grid’s performance. When a hurricane came through in 2005, Alpha’s UPS systems kept the intersections operating for fourteen hours. This helped ease congested traffic, but in light of the recent devastation from Hurricane Katrina in New Orleans, the question was whether fourteen hours was long enough. So, Robert Lewis, City Traffic Engineer for the City of Suffolk began to look for ways to extend intersection runtime. Robert Lewis had particular requirements: an all-in-one, easy-to-install cabinet for his critical intersections.

“I worked very closely with Critical & Emergency Power Systems and RGA who in turn worked very closely with their manufacturer, Alpha Technologies,” said Lewis. “Alpha took our Stationary DC Generator/UPS idea and ran with it. They came back with some conceptual ideas, which we provided input on and the solution was created.”

Jim Merritt, working together with Andy Keel, President of RGA, a manufacturer and distributor of traffic control products with over twenty years of traffic industry experience in the Mid-Atlantic area, suggested the hybrid Stationary DC Generator/UPS solution for unlimited backup time. Lighting at these intersections had since been retrofitted with LED bulbs, making the UPS choice much easier.

The system configuration was made up of the following: Alpha’s FXM UPS and an AlphaGenTM stationary DC generator housed in an Alpha CE3X enclosure with sidecar attachment.

“Alpha’s longstanding history of twenty-five years specializing in outdoor power backup, as well as their breadth of products allowing for numerous configurations, made them a strong power solution provider,” Merritt said. “The AlphaGenTM was already a deployed product in the Cable industry meaning that the training and maintenance curve would be quicker and more efficient.”

“Some of the other localities have expressed interest in this application,” Keel said, “but it’s not something that can be done without planning. This is a new application and the investment is significant. We are missionaries telling a new story.”

In order to justify the cost of such an application, there are many factors to consider. First, the cost of manpower is enormous when a large power outage occurs, as cities generally dispatch police officers to direct traffic at uncontrolled intersections and public works officials to repair costly damage. Additionally, when disasters such as hurricanes happen, affected areas are often heavily taxed in an effort to balance out the tremendous costs.

Suffolk is an outstanding example of a city that operates proactively to ensure its intersections remain safe in the event of an outage resulting from any range of causes including poor utility power and extreme weather conditions.

City of Overland Park, K
Bruce L. Wacker, Supervisory Civil Engineer for the City of Overland Park knows all too well what can happen in the event of a natural disaster. When struck with an ice storm in January 2002, over 30% of Overland Park’s traffic lights were out at one point in time. While it is difficult to know the exact number, the police estimate that 15 traffic accidents occurred during this time as a result of darkened intersections.

In an effort to prevent this from happening again, Overland Park began investing in power backup for its intersections. Wacker describes his city’s plan as a two-part setup. First, a UPS BBS was installed to run the traffic signal in the event of a power outage. When triggered, the BBS begins a time clock that sends the information to a generator. Next, if the utility power is still down after ten minutes, a stationary DC generator will start up, run to stabilize and then will take power and charge the batteries to run the signal. The generator backup system will continue to operate until the utility power is restored.

When planning a power backup strategy for any city, one big question is prioritizingwhich intersections will have BBS installed. Wacker took a visionary approach to this by installing BBS at all primary and many secondary intersections. Furthermore, every primary intersection was complemented with a CCTV camera.

These cameras continue to serve two purposes:

  • Monitor traffic at large intersections with a UPS and backup generator.
  • Zoom in to secondary intersections that can be monitored within a control center. When the control center sees that the secondary intersections are running on backup battery power, a portable generator is brought to the site, providing enough power to the intersection so it will remain in full operation until the power is restored.

Both the City of Suffolk and the City of Overland Park have taken proactive measures to address today’s issues with utility power and traffic intersection safety. For more information about advanced battery backup systems, please visit www.rga-traffic.com, www.cepsi.biz, or http://www.alpha.com/.