1. Signal Patterns for Improving Light Rail Operation Wintana Miller, Associate Transportation Engineer With Mark Madden, P.E., P.T.O.E. DKS Associates

2. Transportation in Tacoma Initial Pilot Project Update to Project Signal Timing Whats Next Signal Patterns for Improving Light Rail Operation

3. Transportation in Tacoma

4. Downtown Tacoma

5. Tacoma Link Light Rail

6. Initial Pilot Project

7. Parties Involved Problems Found Methodology Challenges Initial Pilot Project

8. City of Tacoma Sound Transit Pierce Transit DKS Associates – Technical Advisers Parties Involved

9. Periodic Gridlock Train Headways: 10 minutes (600 seconds) Signal Cycle Length: 70 seconds Potential Solution: Coordinate Train and Signal Operation Problems Found

10. Main Objectives: Compatible cycles = repetitive operation Same time base = predictable action across systems Predictable train travel times Coordinating Train and Signal Operations

11. Picking a Compatible Cycle Length 100 second cycle Synchronized Clocks US Official Time: Atomic Clock in Colorado Springs Sound Transit Train Data Set Train Schedule Project Method

12. Time Space Diagram

13. External Logic Allowed for One Timing Plan Conservative dwell times Unable to use check out detectors No event plans or seasonal variations Remaining Challenges

14. City of Tacoma in the process of upgrading signal system New signal system has been selected Fine tuning LRT operations Signal System Upgrades?

15. Project Update

16. New Plan Needed New Light Rail Parameters New Traffic Signal Parameters Unique Phasing for Preempts New Signal Pattern Development

17. Driven by New Station Construction New Station in Place Before New Controllers Need for New Plans

18. Train Headways Train Travel Times Station Dwell Times New Light Rail Parameters

19. New Headway New Cycle Lengths 90 seconds New Pedestrian Timing (per 2009 MUTCD) Decreased walking speed from 4.0 ft/sec to 3.5 ft/sec New Traffic Signal Parameters

20. Unique Phasing for Preempts

21. Normally two phases Train preempt activate left turn phase Avoiding the left turn trap Commerce St Phasing

24. Support 120 second cycle length Shorter dwell times during off-peak hours Longer dwell times for special events Whats Next?

25. Thank You