Many departments of transportation are in the same position with their signalized intersections. Traffic signals are most likely to lose power during natural disasters, extreme weather, or other emergencies—in other words, when they're needed most to keep citizens and emergency responders moving. Yet aging batteries and maintenance backlogs may leave many traffic signals without working backup, likely to fail when they're needed most.
So, here's a tip from the earthquake zone: the best way to be ready for emergencies is to choose and maintain backup solutions so they will perform when you need them. For signalized intersections, that includes maximizing battery life in your backup systems. If you are using lead-acid, be sure to adhere to the manufacturer recommended maintenance and replacement regimen or choose the longest-lived batteries you can get (for example, nickel-zinc batteries with two to three times the battery life of traditional lead-acid and low maintenance requirements offer a compelling alternative to traditional lead-acid batteries). Then choose UPS technology that extends battery life, for example, by charging properly but also actively monitoring and managing incoming power to minimize switchover to battery backup. And choose technology that's easy to maintain, so you can avoid maintenance backlogs.
The upside of always-ready emergency solutions is that the time and money you save on maintenance and replacements can be used to improve everyday operations. So, if the worst happens, you're ready, and if it doesn't, it's a win- win.