Deployment of Adaptive Traffic Signal Control Pilot in VDOT June 28, 2012 Dean H. Gustafson, PE, PTOE Regional Operations Director for Staunton and Culpeper Districts With permission from Michael Clements, PE and Michael Fontaine, PE, PhD
Adaptive Traffic Control System (ATCS) Advertisement We don t make the traffic signals along your commute to work; We make the traffic signals on your commute greener. 2
Traffic Signal Control Current Practice Actuated control Time-of-day plans by day of week Relies on regular retiming Does not respond well to changes in flow Adaptive control Optimizes on the fly locally and globally No fixed phase order, cycle length, or splits Adapts to unexpected variations in flow 3
The ATCS Challenge Global Optimization Local 4
Goals & Benefits of VDOT s ATCS Initiative Adaptive Traffic Control Systems (ATCS) Benefits: Improve Congestion/Delay/Travel Time with better traffic flow Improve Safety with less stop and go conditions Improve Environment with reduced emission & fuel consumption Improve Incident Management with Real-Time Signal Responses 5
The Process Sees/Vision Responds Optimizes Ethernet Connection Inputs Detector Call 6
Corridor Selection Factors Selection Factors Daily and weekly fluctuations in traffic flow Heavy traffic volumes Highly variable traffic patterns Special events and non-recurring traffic congestion Requires frequent re-timing due to changing traffic volumes and patterns Heavy side street traffic flow (but not oversaturated on all 4 approaches for extended periods of time) Corridor of Statewide Significance (CoSS) Conflicts with other traffic modes (peds, transit, etc.) Support from local authorities 7
ATCS Pilot Project Corridors Installed U.S. 29 in Fauquier County (Warrenton) ~ 6 intersections U.S. 11 in Frederick County (Stephenson) ~ 6 intersections U.S. 250 in Charlottesville/Albemarle County (Pantops) ~ 8 intersections U.S. 17/50/522 in Frederick County (I-81 Exit 313) ~ 6 intersections Route 277 in Frederick County (I-81 Exit 307) ~ 6 intersections Route 7 in Winchester/Frederick County (I-81 Exit 315) ~ 12 intersections Route 620 (Braddock Rd) in Fairfax County ~ 5 intersections 8
ATCS Pilot Project Corridors Purchased U.S. 340 in Waynesboro ~ 12 intersections U.S. 250 in Staunton ~ 10 intersections Route 20 in Albemarle County ~ 2 intersections (added on to US 250) U.S. 17 in York County ~ 22 intersections (Phase 2) U.S. 17 in Isle of Wight County (south of JRB) ~ 4 intersections Route 419 in Roanoke ~ 12 intersections 9
Research Overview Traffic Engineering Division is working with Regions to deploy test cases VCTIR is performing before/after evaluations Objectives: Assess system effectiveness Determine situations where adaptive control provides the most benefit Project is still underway 10
Evaluation Mainline operations Travel time Speed Stops Side street operations Delay Changes in crashes Data sources: floating car runs, Bluetooth, INRIX Data 11
Sample of Results US 250 in Charlottesville US 29 in Warrenton Braddock Rd in Fairfax Future Plans 12
US 250 Pantops Deployment Corridor Length - Approx 3 miles 13
Results Mainline Travel Time Time Period Direction Before After Change AM Peak EB 7:06 4:54-2:12 (-31.0%) WB 11:10 6:28-4:42 (-42.1%) Midday EB 7:01 5:05-1:56 (-27.6%) WB 7:46 6:34-1:12 (-15.5%) PM Peak EB 9:08 5:18-3:50 (-42.0%) WB 7:41 5:47-1:54 (-24.7%) 14
Results Mean # of Stops Time Period Direction Before After Change AM Peak EB 4.00 1.55-2.45 (-61.3%) WB 7.83 2.77-5.06 (-64.6%) Midday EB 3.52 1.26-2.26 (-64.2%) WB 4.55 2.53-2.02 (-44.4%) PM Peak EB 5.55 1.15-4.40 (-80.0%) WB 4.60 2.00-2.60 (-56.5%) 15
US 29 Warrenton Corridor Length - Approx 10 miles 16
Results Mainline Travel Time Time Period Direction Before After Change AM Peak NB 13:09 12:37-0:32 (-4.1%) SB 12:14 11:36-0:38 (-5.2%) Midday NB 12:15 11:46-0:29 (-3.9%) SB 12:02 11:45-0:16 (-2.2%) PM Peak NB 12:14 12:27 +0:13 (+1.8%) SB 12:33 12:57 +0:24 (+3.2%) 17
Results Mean # of Stops Time Period Direction Before After Change AM Peak NB 2.88 2.17-0.72 (-25.0%) SB 1.88 1.06-0.83 (-44.1%) Midday NB 2.35 1.17-1.19 (-50.6%) SB 2.06 1.00-1.06 (-51.5%) PM Peak NB 1.65 1.75 +0.10 (+6.1%) SB 1.94 1.88-0.06 (-3.1%) 18
Braddock Rd Corridor Length - Approx 2 miles 19
Using INRIX Data to Examine Performance 20
Observations at Braddock InSync generally improved WB traffic, but increased delay EB in the morning Mainline stops generally declined Issues at the congested intersection of Braddock and Ox Rd (SR 123) System has been turned off and will be re-evaluated 21
Lessons Learned So Far System can produce very significant reductions in travel times and stops Effectiveness may be limited when: Intersections are over saturated Corridor already functions well Spacing between intersections is very wide, causing platoons of traffic to break up Communications are unreliable 22
Initial Results, Challenges & Lessons Learned Before & After Studies Results U.S. 250 (Pantops) in Charlottesville/Albemarle County Route 620 (Braddock Rd) in Fairfax County Lessons Learned ATCS no better in over-saturated conditions Spend time/money on collecting off-peak data Queues matter Broadband Communications is KEY Public expectations need to be addressed in urban areas Beware of controller actuated beacons Double check IP addresses (and then check again) 23
Using Technology to Move Forward ATCS Central System cable hub InSync Tesla Data Collection BlueTooth technology for travel time/delay INRIX data for continuous monitoring Monitoring Bringing the video feed back to the Traffic Operations Center Communications plan 24
Using Technology to Move Forward INRIX Sample 25
Using Technology to Move Forward Intersection Web View 26
Using Technology to Move Forward Northwestern Region TOC View of ATCS Corridor 27