Adaptive Signal Control Technology: Managing Risks, Achieving Objectives

1. Adaptive Signal Control Technology:  Managing Risks, Achieving Objectives Eric Graves, P.E. City Traffic Engineer Alpharetta, Georgia

2. Alpharetta Transportation System • 50,00 Residents • Day Time Population~100,000 • ADP • HP • UPS • North Point LCI • Downtown LCI

3. Alpharetta Transportation System • 4 Interchanges with GA 400 (Limited Access Freeway) • 7, 4-6 Lane Arterial Streets • ~ 120 Traffic Signals • 3 Emergency Signals at Fire Stations • 1 Hawk Signal – April • All newer equipment – GDOT ATC Program • 332 cabinets • 2070 controllers – SEPAC Firmware • Ethernet Communications • 60% direct connections to City TCC

4. Traffic Operations • 2 Public Works Crews • Signs • Signals • 1 Signal Systems Engineer • 1 Traffic Engineering Technician • Inspect Construction Projects • Manage maintenance contracts • Striping • Loop Repairs

5. Traffic Operations • Signal Systems Engineer • Signal Timing Maintenance Program • Systemic timing of all traffic signals every 2-3 years • Before/After travel time measurements • Timing reports to be published on the City Web Site (soon)

6. Why Adaptive?? • Less $$ available for capacity improvements • Less opportunity for new roadway connections • Alpharetta is land locked and nearly built out • Essential we operate our system as efficiently as possible • Initiative included • Systems / Timing Engineer • PM Program • Timing Maintenance Program

7. Why Adaptive ?? • Traffic STILL a top concern from citizen survey • What else can be done??? • Cobb County SCATS System • Councilman read article on SCATS Success • Directed Staff to investigate options for Alpharetta

8. When Adaptive Makes Sense • Unpredictable Traffic Flow • High sustained growth • Freeway system interactions

9. When Adaptive Makes Sense • Agency Capabilities • Technician capabilities • Detection at 98%!! • Strong communications • Fiber along all major corridors • Stable Ethernet field network

10. When Adaptive Makes Sense • Agency Capabilities • Engineering Staff • In-house signal timing maintenance program • “One of the best signal timers in the state”

11. When Adaptive Makes Sense Desire Continuously Optimized Timings!!

12. Alpharetta Adaptive Signal Evaluation: Hypothesis A well-timed system is a well-timed system • Cycle length- appropriate for volume • Split percentages- balanced or prioritized • Offsets- provide good progression

13. Alpharetta’s Criteria • Should be able to perform close to manual optimized timings • Maximize the utilization of existing infrastructure • 332 cabinets/ 2070 controllers/ SEPAC Firmware • Ethernet Communications/ECOMM • Optimize Progression on Corridors • Provide Queue Management • Coordinate crossing arterials?? • Manual control?? • Special events/Seasonal Peaks/Incidents

14. Identified Solutions SCATS – Cobb County SCOOT **OFFERED DEMO** ACS Lite InSync **OFFERED DEMO**

15. Identified Solutions • The City of Alpharetta performed demonstration projects with two adaptive platforms • InSync and SCOOT • The results of the demo projects indicated that adaptive solutions could replicate current timing efforts • Potentially improving operations for special events, unexpected events, and off peaks periods

16. Other Systems Considered • SCATS • New Firmware • New Detection • Separate Central System • OPAC • New Firmware • Separate Central System • Distributed solution – more rigorous detection requirements • ACS Lite • Presently not available in TACTICS • Presently does not optimize cycle length

17. Next Steps • SR 9 • Sandy Springs • Roswell • Alpharetta • GDOT • 18 mile corridor • Collector between outer suburbs and GA 400 interchanges • Primary arterial (Sandy Springs/Roswell) • Back up for GA 400 • PM Team identified Adaptive as an ITS Strategy

18. SR 9 ATMS Project • PM Team initially considered performance Spec • FHWA/GDOT indicated that as written only one vender likely fulfilled requirements • FHWA determined documentation was insufficient to sole source

19. SR 9 ATMS Project • GDOT/FHWA Required PM Team to follow Federal Regulations mandating System Engineering Process to select Adaptive Solution

20. SR 9 ATMS Project • Systems Engineering Report completed and accepted by FHWA • Systems Engineering Process identified similar functional requirements as the Alpharetta demo projects • SCOOT determined as preferred option • Compatible hardware with jurisdiction platform • Ability to coordinate with non-adaptive intersections using Tactics Central System

21. SR 9 ATMS Project • Project recently received NTP!!

22. Questions?? egraves@alpharetta.ga.us eveith@alpharetta.ga.us