Super Capacitor Evaluation and Statewide Deployment, Utah DOT

The Challenge | Evaluation Process | Results | Conclusion

Executive Summary

In 2024, the Utah Department of Transportation’s (UDOT) Traffic Management Division undertook a targeted effort to harden its Intelligent Transportation Systems (ITS) against power interruptions and extreme weather. Utah’s geography and climate routinely expose traffic control field devices to sub‑zero temperatures, high heat, and remote, off‑grid conditions. For Battery Backup Systems (BBS), these harsh environments rapidly degrade conventional lead-acid batteries, shortening lifecycles and requiring frequent, costly maintenance and/or replacement. For this project and evaluation, a roadway safety minimum of four‑hour backup power and enable continuous remote awareness was established as a criterion. A UDOT–sponsored capstone team evaluated and designed a cabinet‑integrated backup solution centered on evaluating newer graphene‑based supercapacitor technology paired with a double‑conversion Uninterruptible Power Supply (UPS) system, complemented by a remote monitoring dashboard that leveraged existing site telemetry.

The Challenge

UDOT’s ITS network includes Closed‑Circuit Television (CCTV) cameras for visual verification, non‑intrusive detection devices, Variable Message Signs (VMS), traffic monitoring systems, and intelligent traffic signal infrastructure spread across regions that range from desert valleys to high‑elevation, subalpine corridors. Many devices operate off‑grid on solar power, which requires energy storage capable of charging during daylight and reliably discharging at night or during extended cloud cover. In practice, traditional lead‑acid batteries presented multiple barriers: in cold, high‑elevation locations they did not provide sufficient power, recharged too slowly, and in some cases would not recharge at all; in hot environments they suffered accelerated degradation. The median service life of roughly five years was further shortened by thermal stress and frequent deep cycles. Batteries were heavy, which limited safe pole‑mounting options and complicated field handling. They contained hazardous materials and chemicals that pose safety and environmental risks if damaged. The operational consequences were significant, including outages at critical times, degraded traffic management in weather events, and repeated site visits to replace or service depleted batteries.

Due to this resource- and capital-intensive situation, UDOT set specific performance requirements for a cabinet‑integrated backup power system, emphasizing a minimum of four hours of runtime at a constant load, survivability from 0°F to 140°F or better, and an extended service life with minimal maintenance. The agency also wanted remote visibility into power system status, both to reduce unnecessary field visits and to manage energy assets more intelligently across regions. The Brigham Young University (BYU)‑UDOT Capstone team’s scope was to design a dependable BBS and build a data display dashboard that integrates with existing solar sites, charge controllers, and communications protocols, all while fitting the constraints of the state’s deployed standard Econolite traffic cabinets and the scale of UDOT’s field operations.

The Evaluation Process

The evaluation process began with a structured assessment of functional requirements, environmental constraints, integration boundaries, and human factors that would govern installation and maintenance. The team anchored cabinet fit and mounting design to Econolite’s Safetran 336 Series cabinet form factor, the smaller of UDOT’s commonly used cabinets, which assured compatibility with the larger Econolite Safetran 334 Series cabinet. This drove a rack‑mount architecture using standard 19‑inch rails, ensuring that any selected energy storage and UPS components could be safely installed, secured, and serviced without custom fabrication. Finite element analysis of mounting brackets and fasteners confirmed sufficient safety factors across likely load paths, accounting for the mass of the storage module and shock loads typical of cabinet environments.

From the energy storage perspective, the capstone team compared a graphene‑based supercapacitor module, the Econolite ZX2000‑48, a 48 VDC, 2,000 Wh, rack‑mount unit, against the incumbent NorthStar NSB 210FT Blue+ lead‑carbon solution. Achieving 48 VDC with lead‑acid would require four 12 V units in series, multiplying mass and service complexity. The ZX2000‑48’s advertised capabilities included a 20‑year operational life, essentially no routine maintenance, a very wide operating temperature range of –40°F to 167°F, and a weight of approximately 48 lbs. per module, all in a 19‑inch rack form factor. In contrast, four NSB 210FT units weighed more than 600 lbs. combined and were typically replaced by UDOT every five years under non‑ideal conditions, with narrower temperature limits and the well‑known cold‑weather charging constraints of chemical batteries. The lifecycle cost comparison, when normalized over three decades of service, favored the supercapacitor despite higher unit cost, because repeated replacements, labor, and downtime for lead‑acid installations compounded dramatically over time.

The power conversion and management layer was addressed with a double‑conversion UPS from the DBLMXU‑48 family, which can provide pure sine wave output at 120 VAC, cold‑start capability, and zero transfer time during brownouts and outages while conditioning line power during normal operation. This architecture allows continuous AC service to cameras, radios, and controllers, and ensures that when utility power dips below threshold the UPS instantaneously sources from the storage module. Just as importantly, the UPS communicates via Simple Network Management Protocol (SNMP) over Ethernet, furnishing the data points and telemetry necessary for the remote monitoring dashboard and interoperability with existing site communications.

To validate runtime claims under realistic loads, the team modelled power budgets for combined CCTV and TMS sites. UDOT set a baseline of a constant 2‑amp draw at 120 VAC, roughly 216 W continuous, with transient spikes up to 5 amps. Using manufacturer datasheets and conservative derating, the ZX2000‑48 plus DBLMXU‑48 stack was calculated to provide approximately 9.25 hours of runtime at the 216 W average load, comfortably more than double the required four hours. The vendor’s published backup timetable cited two hours at 1,000 W, four hours at 500 W, and eight hours at 250 W; extrapolating to 216 W yields the 9.25‑hour estimate. While long procurement lead times prevented full‑scale instrumented tests on production‑version units within the capstone calendar, the team verified transfer performance using loaned, earlier‑generation units provided by the vendor. In those demonstrations, the UPS transitioned cleanly from grid to storage without service interruption to a representative camera and radar load, validating the control behavior central to the design.

Mechanical integration and thermal suitability were assessed together. Because supercapacitors store energy electrostatically rather than chemically, their usable capacity remains far more stable at temperature extremes than traditional batteries. This characteristic was essential for UDOT’s highest‑altitude and hottest‑desert deployments. The cabinet design intentionally avoided active heating pads or cooling hardware, relying instead on the supercapacitor’s broad operating window and the passive thermal behavior of the cabinet.

In parallel with the hardware design, the team built a monitoring dashboard to unify battery and solar array status across sites. To accelerate value and minimize integration risk, the software tapped existing Morningstar charge controllers already in UDOT solar sites, pulling data via IP and scraping the MSView interface to populate the dashboard. The UPS’s SNMP interface provided battery and system telemetry, enabling the same dashboard to present supercapacitor state of charge, voltage, temperature, and alarms. Tested on a MacBook Pro host with the controller connected by Ethernet, the prototype consistently retrieved and displayed live data, validating the communications chain and offering a clear path to map‑based views, alerting, and historical trend storage in future iterations.

Crucially, this engineering work took place alongside an agency‑led innovation track. UDOT’s Deputy Fiber Optics Manager initiated a collaboration with BYU engineering students to study supercapacitors for traffic signal backup systems. As the exploration matured, field staff in Region Four partnered with Econolite to adapt the technology for ITS devices, installing the first off‑grid supercapacitor powering a CCTV site on SR‑143 near the Town of Brian Head during the late 2024 winter season. The field result was sufficiently strong that Region Four began planning to replace nearly two dozen battery systems with super capacitors over the next few years, while Region Three identified half a dozen challenging off‑grid sites for upgrades. Additional trials extended to traffic count sites, and work continued applying the approach to traffic signals, signaling a broadening, agency‑wide confidence in the BBS/UPS technology.

Results

The final deliverable mechanical, electrical, and software design combined performance surpassed UDOT’s baseline requirements. Against the four‑hour runtime target, the supercapacitor‑UPS combination produced an estimated 9.25 hours at a representative 216‑watt load, affording operators a larger buffer during extended outages and storm events when truck access can be delayed. Where batteries had to survive from 0°F to 140°F, the chosen supercapacitor operates from –40°F to 167°F without derating—removing the need for cabinet heaters in cold climates and reducing thermal management complexity overall. And instead of a five‑to‑eight‑year service life, which UDOT often saw shortened to roughly five years in non‑ideal conditions, the super capacitor’s expected 20‑year operational life and 100,000s of cycle endurance eliminate normal replacement schedules. The capstone team quantified charge time, estimating approximately 2.53 hours for a full recharge under typical conditions, which further supports resilience in repeated short‑duration outages.

Lifecycle economics sharpened the picture. Although a ZX2000‑48 module carries a higher purchase price than a four‑battery, 48‑volt lead‑acid array, the cumulative cost of repeated battery replacements, technician labor, travel, and downtime over two decades tipped the balance decisively toward the supercapacitor. The Final Design Report contrasted a single 48 lb. supercapacitor module with more than 600 lbs. of four 12‑volt lead‑carbon units, highlighting safer handling, more flexible mounting, and the opportunity to store greater watt‑hours within the same cabinet footprint by paralleling additional modules as needed. Because supercapacitors are not chemical batteries, they avoid hazardous materials concerns, are fully recyclable, and present fewer risks in vehicle impact scenarios—delivering operational, environmental, and safety benefits in one platform shift.

Results from UDOT’s internal innovation program corroborated the design conclusions with field evidence. In the Brian Head deployment, the super capacitor BBS solution maintained service through the tail end of a severe winter at elevation, addressing exactly the cold‑weather charging limitations that had hamstrung traditional batteries. With that success, UDOT documented the initiative in its Innovation Catalog, noting the technology’s ability to sustain repeated charge–discharge cycles, maintain storage capacity in cold climates, reduce weight and installation effort, and appreciably cut maintenance. The catalog entry also summarized an efficiency case: a 15‑plus‑year lifespan, annual labor savings, and a favorable three‑to‑one benefit–cost ratio, with a forecasted cost avoidance on the order of $195,000 over fifteen years. While the evaluation horizon emphasized a 20‑year operational life consistent with vendor literature, the agency’s near‑term planning window still produced a compelling economic justification at the fifteen‑year mark, about half of the solution lifecycle.

From an integration standpoint, the solution respected UDOT’s installed base. By using the Econolite cabinet ecosystem, rack standards, and SNMP communications, the design required no exotic interfaces or bespoke enclosures. The prototype dashboard demonstrated interoperability with Morningstar charge controllers already deployed at solar sites, offering an immediate avenue to consolidate visibility across district operations. In the Final Design Report, the team outlined pragmatic future enhancements such as map‑based site selection, advanced search, historical data storage and graphing, and alarm thresholds that align with advanced traffic management center workflows and could be seamlessly implemented incrementally without disturbing existing or future field hardware.

Importantly, the results carry implications beyond a single corridor or device class. UDOT’s catalog notes that supercapacitors are being evaluated and adopted for multiple use cases: off‑grid CCTV, traffic count stations, and signal backup applications, across UDOT Regions One through Four and central divisions spanning Traffic and Safety, Traffic Management, Research and Innovation, and Performance and Asset Management. The cross‑functional nature of the development team, combining agency staff and vendor engineering support, accelerated knowledge transfer and created a repeatable template for other challenging sites. The technology’s lighter weight and modularity also open opportunities where pole loading and cabinet space previously constrained design choices.

Conclusion

UDOT’s 2024 supercapacitor initiative, reinforced by the BYU‑supported design and validation effort, demonstrates a clear path to more reliable, sustainable, and cost‑effective backup power for ITS infrastructure. The cabinet‑integrated architecture meets and exceeds runtime and environmental requirements, the monitoring dashboard provides actionable visibility using existing site data flows, and the lifecycle economics favor a shift away from chemical batteries that struggle in Utah’s extremes. As of this writing (March 2026), UDOT has purchased, and deployed statewide, 263 Econolite Super Capacitor systems with a total of 345 Super Capacitor power modules

The combined engineering and field evidence suggest that super capacitors are not only viable but advantageous for powering signals and ITS devices in Utah’s most challenging environments, positioning UDOT to deliver more sustainable mobility while enhancing safety and providing better stewardship of public resources.