Introduction

For years, traffic authorities have faced an impossible choice when installing Accessible Pedestrian Signals (APS): either accept a higher cost of installation and disruption due to running new wiring, or implement an existing 2-wire system that either doesn't perform as reliably in real-world conditions or requires the installation of even more components.

The Guardian® Duo eliminates that compromise entirely.

What Guardian® Duo Does

Guardian® Duo transforms any intersection's existing push button setup into a fully-featured APS installation. Pedestrians get the audible tones, vibrotactile feedback, and visual indicators they need for safe crossings, while traffic authorities gain remote monitoring capabilities and simplified maintenance, all through the same two field wires that were already there.

The system works by sending both power and data through existing field wires using our custom powerline communication technology. Unlike wireless solutions that require radio pairing or independent systems that need new wiring to the pedestrian signal heads, Guardian® Duo simply fits into your current setup and syncs your entire intersection with the push of a button.

How It Solves Real Problems

The Installation Challenge: Traditional APS retrofits require either new cables underground or installing equipment in pedestrian signal heads. Both approaches mean construction, traffic disruptions, and more costs. The Guardian® Duo installs in hours, not days or weeks, all while using existing infrastructure.

The Reliability Problem: Current 2-wire APS systems use wireless-style RF technology that struggles with the branched, spliced underground wiring common at intersections. Our powerline communication interface was designed specifically for these harsh conditions, maintaining reliable operation even through 1000-foot cable runs with multiple splices.

The Maintenance Burden: Many APS installations require technicians to visit each intersection for configuration and troubleshooting. Guardian® Duo's web-based monitoring portal lets you check system status, review pedestrian activity, and receive alerts remotely, reducing service calls and improving response times.

What's New and Different

Advanced Powerline Communication

While other 2-wire systems adapt wireless technology for wired use, Guardian® Duo uses purpose-built powerline communication that thrives in real underground wiring conditions. The system operates reliably even with significant interference and can function safely with up to 66% packet loss, ensuring pedestrian safety is never compromised.

Hall Effect Push Button Sensor

The new Hall effect sensor provides a more natural button feel compared to traditional piezoelectric switches. Users get tactile feedback similar to conventional push buttons, while the system gains electrical reliability by removing stress from sensitive components. The sensor activates with less than 2 pounds of force and has been tested through over 8 million cycles without failure.

Enhanced Light Bar

The rectangular 3-segment LED light bar replaces the traditional round pilot light with dramatically improved visibility in bright sunlight. The optimized optics provide better visibility from all angles without increasing power consumption, while the multi-segment design enables future expansion for diagnostic and user feedback functions.

Standard Wave Sensor

Touchless activation comes standard on every Guardian® Duo Station. The Wave sensor, proven reliable since 2020, allows touch-free push button activation for pedestrians who cannot physically press the button. Recent improvements address performance during extreme lighting conditions at dawn and dusk.

Installation-Friendly Design

Installer feedback drove practical improvements: expanded wiring access eliminates the finger space problems of earlier designs, while a gasketless water protection system prevents the sticky door issues that complicated field maintenance. The multi-layer water management approach keeps connections dry without the gasket problems that plagued previous generations.

Simple System Architecture

Guardian® Duo consists of three main components that work together seamlessly:

Guardian® Duo Station: The street-side push button that pedestrians interact with. It looks and feels familiar while delivering advanced functionality through existing 2-wire connections.

Duo Card Rack Controller: A cabinet-mounted unit that manages up to 16 push buttons across an intersection. It interfaces with your existing traffic controller and provides network connectivity for remote monitoring.

Duo Power Supply: Supplies clean, isolated power for the entire system from standard 120VAC cabinet power.

Built to Last

Guardian® Duo underwent extensive testing to ensure reliable operation in all conditions:

• Temperature extremes: Full operation from -40°C to +80°C with rapid thermal cycling
• Vibration Immunity: Withstands traffic vibration, wind effects, and mechanical shock
• Lightning Protection: Survives multiple lightning strikes exceeding industry test standards
• Ice Operation: Functions normally even with ice buildup on the button face
• Electrical Interference: Maintains communication through severe electrical noise

The first installation in Boise, Idaho, has operated flawlessly since May 2025, demonstrating the transition from laboratory testing to real-world reliability.

Network Monitoring Made Simple

The Guardian® Duo web portal provides at-a-glance status information for your entire intersection. See which push buttons are active, monitor pedestrian call patterns, and receive automatic alerts for system issues. SNMP integration allows connection to existing traffic management systems for centralized monitoring across multiple intersections.

Why This Matters Now

Federal accessibility requirements continue to expand APS installation mandates, while municipal budgets remain constrained. Guardian® Duo enables compliance without the traditional infrastructure costs, making it possible to address accessibility requirements across entire jurisdictions rather than just a few high-priority intersections.

The system's reliability also reduces long-term maintenance costs. Remote monitoring capabilities mean faster response to actual problems while eliminating unnecessary service calls for systems that are operating normally.

The PedSafety Difference

Guardian® Duo builds on years of field experience with our Guardian® 5.0 and WiAAPS® products. We've incorporated installer feedback, addressed real-world reliability challenges, and maintained the plug-and-play simplicity that traffic authorities expect from PedSafety products.

Our design philosophy focuses on practical solutions rather than theoretical capabilities. Every feature has been tested extensively, and the system architecture prioritizes safety and reliability over complexity.

Ready for Deployment

Guardian® Duo is available now and ready for installation at intersections nationwide. Whether you're addressing a single intersection or planning jurisdiction-wide APS deployment, Guardian® Duo provides the reliability, functionality, and cost-effectiveness to make your project successful.

Learn more at: pedsafety.com/guardian-duo