Case Study
Alicia Parkway Traffic Light Synchronization Program (TLSP)
The Challenge | The Solution | Results | Conclusion
Executive Summary
Alicia Parkway, a critical east–west arterial in Orange County, CA, supports more than 60,000 vehicles per day and connects six jurisdictions across an 11 mile corridor with 41 signalized intersections. As part of Orange County Transportation Authority’s (OCTA) countywide Traffic Light Synchronization Program (TLSP) that was funded under Proposition 1B and Measure M, the corridor was selected for comprehensive ITS modernization to improve mobility, reduce vehicle emissions, and enhance travel-time reliability.
To meet these objectives, agencies deployed Centracs® ATMS and Econolite traffic signal controllers, enabling coordinated operations across multiple cities and Caltrans jurisdictions. The system delivered substantial improvements, including reduced stops, travel times, and greenhouse emissions. Fuel savings are projected to exceed 1.1 million gallons over three years.
The Challenge
Despite being located in a largely suburban area, the Alicia Parkway corridor experiences sustained urban level congestion, especially at segments near Interstate 5 (I 5), the region’s primary north–south freeway. The corridor spans six agencies, including the cities of Aliso Viejo, Laguna Hills, Laguna Niguel, Mission Viejo, Rancho Santa Margarita, as well as Caltrans managed areas. This presented a significant multi-jurisdictional coordination challenge due to disparate systems, varying operational practices, and inconsistent communications infrastructure.
Prior to the TLSP deployment, the corridor suffered from:
- Frequent stops and delays during morning and evening peaks
- Inefficient corridor progression between jurisdictions
- Aging communication systems and limited inter‑agency connectivity
- Rising vehicle emissions due to stop‑and‑go conditions
OCTA required an interoperable, scalable, centrally managed ATMS solution capable of communicating over a mix of fiber optic, Ethernet networks, and existing copper serial infrastructure, while being compatible with multiple city IT standards, virtual server environments, and project budget constraints.
The Solution
To modernize the corridor and unify local operations, OCTA and participating agencies implemented a multi phase ITS upgrade centered around Econolite’s Centracs ATMS, executed as part of the broader Prop 1B TLSP initiative covering 153 miles and 533 intersections countywide.
System Deployment Elements
- Installation of two Centracs ATMS systems:
- A physical system hosted in Laguna Hills
- A Centracs virtual system integrated into Mission Viejo’s IT environment
- Deployment of Econolite traffic controllers across priority intersections
- Upgrades to communications, including new gigabit fiber optic, Ethernet, and support for legacy copper systems
- Integration of Centracs Server-to-Server for cross agency monitoring, timing plan coordination, and real time operational adjustments
- Development of optimized timing plans for:
- West segment: Crown Valley Parkway → I 5 (24 intersections)
- East segment: Santa Margarita Parkway → I 5 (17 intersections)
Centracs was selected as the turnkey platform due to its scalability, inter jurisdictional capabilities, and flexible architecture supporting IT compliance, virtual servers, and hybrid communications infrastructure.
Results
Before and after studies were conducted across morning, midday, and evening peak periods in both travel directions. The outcomes demonstrated immediate benefits aligned with TLSP goals.
Operational Performance Improvements
- Up to 75% reduction in number of stops during peak periods
- 31% increase in average speed along key segments
- 11% reduction in overall travel times corridor wide
- 7% reduction in greenhouse gas emissions
- Fuel savings exceeding 1.1 million gallons projected over three years
These improvements translated into smoother progression, reduced acceleration/deceleration cycles, and improved multimodal efficiency across jurisdictional boundaries.
Conclusion
The Alicia Parkway TLSP deployment is a strong example of how coordinated, multi agency ITS investments can significantly enhance corridor performance, reduce environmental impacts, and deliver long term operational efficiency. By leveraging Centracs ATMS, modern controllers, and upgraded communications infrastructure, Orange County agencies created a unified traffic management environment that supports dynamic operations, scalable growth, and improved safety for all roadway users.
The project demonstrates the power of regional collaboration and intelligent transportation technologies to improve mobility—making Alicia Parkway a model corridor for future synchronization and adaptive signal control initiatives throughout California and beyond.