01672581

Component

http://www.trb.org/Main/Blurbs/175112.aspx

Significant improvements have been made to the Phoenix, Arizona, metropolitan area’s transit system over the last 15 years as a result of local and regional sales tax initiatives. Chief among the improvements was the 20-mi, predominantly in-street, light rail transit (LRT) system, which was planned, designed, and constructed during this time. The purpose of the LRT project was to connect several major employment centers, residential areas, universities, grade schools, the region’s airport, and numerous special event facilities. This required careful planning and route choice to optimize ridership and minimize impacts. It was decided to take advantage of Phoenix’s well-defined grid pattern of streets, and the logical choice for the LRT route was in the middle of key arterial streets, which allowed for parallel streets to absorb the diverted traffic. Most of the 20-mi system was planned, designed, and constructed in the confines of existing streets in the cities of Phoenix, Tempe, and Mesa, Arizona. This caused the system to transverse 150 intersections. During the planning stage of the project, these cities raised concerns that delays to cross-street traffic would be great, and they were also concerned for the safety of motorists crossing the line’s path. Valley Metro desired to maximize operating speed and minimize delays for the trains. Therefore, a unique traffic signal system was needed to attain these goals. These goals were achieved through a comprehensive traffic signal control strategy called predictive priority. Predictive priority allows for the signal system to make adjustments in the traffic signal cycle in response to advanced calls from approaching trains. A peer-to-peer fiberoptic network was built to allow for the exchange of data. Local detection of the trains was converted to a call to intersections further downstream. Cascading peer-to-peer calls allow the train to progress without unplanned stops between stations at traffic signals. The Valley Metro light rail system has been in operation for 6 years. Modifications to the signal system have been made as traffic demands and safety issues have arisen. However, the essential properties of the predictive priority system have not changed and still perform well to this day. When planning began on the Valley Metro light rail system, there were concerns about meeting all the demands of implementing an in-street rapid transit system. The predictive priority system addressed all the concerns, and it continues to perform as expected, providing safe, reliable service while not adversely affecting vehicular traffic. Valley Metro is preparing to open up six more LRT miles during the next year, and a similar predictive priority system will be provided for the added 40 intersections.

01613496

English

pp 385-393

2016-9

Transportation Research Circular

13th National Light Rail and Streetcar Conference

9780309450591

Digital/other

Figures; Photos; Tables

Light rail transit; Light rail transit grade crossings; Mathematical prediction; Traffic signal priority

Phoenix (Arizona)

Operations and Traffic Management; Public Transportation; Railroads

TRIS, TRB, ATRI

May 10 2018 10:43AM

• A Workable Solution to Conflicting Crashworthiness Requirements
• Achieving Optimal Results from New Light Rail Lines: Lessons from Three Decades of Experience
• Advancing Safety Rules Compliance: Proactive Management Through Simplified Data Analysis
• Block Rail: Current Best Practices and Experience on Recent Projects
• Compromise: A Necessary Element of Sacramento’s LRT Starter Line
• Denver Regional Transportation District’s Central Rail Corridor Capacity Improvements
• Double-Tracking Baltimore’s Light Rail Transit System
• Downtown Distribution for Light Rail Transit: Past, Present, and Future
• Ergonomics and Visibility in the Tramway Driver’s Cab
• Expanding Metrolink Through Town Centers and Residential and Urban Environments Across Greater Manchester
• Getting a Safer LRT Through a Better Design of Its Insertion in Public Space
• Importance of Bus Connections to Light Rail Accessibility Gains
• Inserting Streetcars into Pedestrian Areas: French Examples
• Insertion of the Purple Line
• Integration of METRO Blue and Green Lines with Buses: Restructuring Bus Service Around New High-Frequency LRT Lines
• Key Directions of the Modernization of Tram Systems in Central and Eastern European Countries
• Key Role of Sustainable Urban Mobility Plan in the Development of Light Rail Train Networks in Central and Eastern European Countries: Case Study of LRT Networks in Romania
• Light Rail Hubs in a Multimodal Transport Environment
• LRT Safety in France: How Are Pedestrians Involved?
• METRO Green Line Transit Signal Priority: Implementation and Lessons Learned
• Mitigation of Hazards for Street Running and Semiexclusive Light Rail Rights-of-Way
• Onboard Energy Storage System Applications on Streetcar Projects
• P3 Experiences and Lessons Learned from the Maryland Purple Line Project
• RandstadRail: From a Traditional Tram System to an Integrated Tram and Light Rail System in the Metropolitan Region Rotterdam–The Hague
• Safety Management in European LRT Systems: Some Tools for Collecting and Using Accident Data
• San Francisco Municipal Transportation Agency’s Twin Peaks Tunnel Trackway Improvement Project
• State of the Art in Light Rail Alternative Power Supplies
• Streetcar Institutional Models: Comparison of Experience with Transit Coordination