Caltrans Validates Hydrogen Fuel Cell System for Extended Intersection Uptime During Emergencies

EQASI-led testing confirms the system's potential to maintain traffic signal operation in high-priority and outage-prone locations across California

SACRAMENTO, CA / August 14, 2025 / The California Department of Transportation (Caltrans) is advancing its emergency preparedness efforts through the successful evaluation of a hydrogen fuel cell backup power system, tested for use at critical signalized intersections during extended power outages.

A hydrogen fuel cell backup power system was installed at a signalized intersection on Lower Sacramento Road in California. These systems support extended intersection uptime during emergencies such as wildfires, power shutoffs, and severe storms.

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Hymax: A hydrogen fuel cell backup power system was installed at a signalized intersection on Lower Sacramento Road in California. These systems support extended intersection uptime during emergencies such as wildfires, power shutoffs, and severe storms.

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

Caltrans's commitment to public safety

Caltrans continues to prioritize public safety through the evaluation and integration of emerging technologies that strengthen California's transportation infrastructure. By identifying solutions that extend signal uptime during wildfires, storms, or other emergencies, the department supports statewide evacuation plans, school zone protection, and mobility in rural corridors. The use of clean energy systems such as hydrogen fuel cells aligns with broader state goals for sustainability and resilience.

EQASI's role in innovation and assurance

The Electrical Quality Assurance and Source Inspection (EQASI) branch of Caltrans' Materials Engineering & Testing Services (METS) division led the evaluation of the HyMax system. EQASI plays a vital role in verifying that contractor-furnished materials meet project specifications and Caltrans standards. Through its work in the New Product Evaluation Program (NPEP), EQASI ensures that new technologies are carefully assessed for safety, reliability, and field readiness before being introduced into the transportation network.

Western Systems and the HyMax system

Western Systems supplied the hydrogen fuel cell system evaluated during this testing. Known as HyMax, the system is designed to provide extended-duration backup power to traffic signal cabinets using compressed hydrogen and a fuel cell engine. While not intended as a replacement for standard battery backup systems, HyMax may serve as an effective site-specific enhancement in areas where longer run times are critical to public safety. The system has already been deployed at more than 50 locations throughout California, supporting agency readiness and uninterrupted signal operation during prolonged power outages.