Smart Preemption and Priority Solutions

Western Systems supports a wide range of preemption and priority applications, including:

• Emergency Vehicle Preemption (EVP)
• Transit Signal Priority (TSP)
• Freight Signal Priority
• School zone speed enforcement
• Multi-vehicle priority coordination (e.g., bus and fire routes sharing corridors)

We help agencies design integrated systems that align with corridor priorities, minimize conflicting calls, and support both legacy and IP-based communications. Solutions are designed to be flexible from intersection-level retrofits to full corridor or citywide deployments.

IR-based preemption uses high-intensity optical signals to communicate between authorized vehicles and signalized intersections from up to 2500 feet which can be reduced, if needed, in downtown areas. Emergency vehicles are equipped with Strobecom II Emitters, which flash coded infrared signals toward approaching traffic signals.  Strobecom II Detectors mounted on the traffic signal mast arm detect the optical signal, then send an electrical signal to the traffic signal cabinet.  The Strobecom II OSP Card located inside of the traffic cabinet verifies the preemption call, and then requests for the traffic signal controller to preempt the appropriate phase, by delivering a green light well before the vehicle reaches the intersection so that any vehicles previously stopped at a red light will have time to proceed and merge to create a clear path.  This reduces intersection delays, stops cross traffic, and improves safety during emergency responses, particularly in complex or congested networks. 

This helps reduce intersection delays, clear cross traffic, and improve safety during emergency responses, particularly in complex or congested networks.

Yes, many of our agency partners are combining emergency preemption and transit signal priority within shared corridors. Through intelligent controllers and conditional logic, we help cities prioritize emergency vehicles while still enabling transit vehicles to request signal priority based on schedule adherence or passenger loads.

We also provide tools to manage and log multiple priority requests at once, ensuring that system behavior aligns with city policy and mobility goals.

Western Systems works with a wide array of industry-leading technologies, including:

• Yunex Roadside Units (RSUs) for connected vehicle applications (N.C. State University example) N.C. State University N.C. State University N.C. State University
• Tomar and StrobeCom II optical emitters and receivers in SoCA
• Multi-Line Signs for dynamic messaging tied to preemption events
• Secure IP communications, cellular, and fiber integrations
• Traffic cabinet upgrades to support dual-priority systems

We design systems that are interoperable and expandable, whether you’re working with legacy detection or planning a full CV2X upgrade.

Most agencies begin with a corridor audit or needs assessment. Western Systems supports every step of the deployment, including:

1. Assessment – Identifying priority corridors and existing infrastructure
2. System Design – Matching technologies to local goals and fleet configurations
3. Installation – Cabinet retrofits, detector setup, and vehicle integration
4. Configuration – Signal controller logic, timing plans, and test scenarios
5. Training and Support – Ongoing performance monitoring and field service

City-wide deployment can be phased or rapid, depending on signal cabinet readiness and fleet outfitting.