The California Department of Transportation (Caltrans) is advancing its emergency preparedness efforts through the successful evaluation of a H₂ fuel cell backup power system, tested for use at critical signalized intersections during extended power outages.

As part of its commitment to improving emergency response and transportation system resilience, Caltrans conducted a formal lab evaluation of the system at its Translab facility in Sacramento. The test was led by the Electrical Quality Assurance and Source Inspection (EQASI) branch, which confirmed uninterrupted operation for 5 days and 18 hours under a consistent electrical load-a major increase from the 4-hour average provided by traditional battery backup systems.

"Our role is to make sure devices function as expected under the conditions they'll actually face - whether that's extreme heat, power loss, or emergency response scenarios. The goal is reliability in all conditions across the State of California. When these systems go into the field, they impact the safety of everyone. That's what drives the precision in our process," said Justin Ellis, P.E., Branch Chief of Electrical Quality Assurance and Source Inspection.

The H₂ fuel cell system evaluated in this study was supplied by Western Systems and is known as HyMax. Designed to support traffic cabinet operations using compressed H₂ and a fuel cell engine, the system offers a site-specific solution for intersections where extended outages could compromise safety or mobility. It has already been deployed at more than 50 locations throughout California.

"We're proud to collaborate with Caltrans on solutions that improve system resilience across the state," said Zach Hoiting, Senior Vice President at Western Systems. "The HyMax system was developed to serve real-world transportation needs-ensuring uninterrupted signal operations in the places and moments that matter most."

Caltrans identified the need for longer-duration backup systems as part of its broader effort to protect evacuation routes, maintain school zone safety, and ensure reliable access in rural corridors. Through its New Product Evaluation Program (NPEP), Caltrans vets new technologies for use on the state highway system with a focus on public safety and field performance.

The successful validation of this H₂-based system reflects Caltrans's leadership in integrating innovative technologies that strengthen infrastructure reliability, helping California communities stay safe, connected, and prepared during emergencies.