Adaptive Traffic Pilot Programs Eli Veith, PE, PTOE

Introduction Adaptive signal evaluation program – Driving factors – Expectations & Objectives Evaluation of InSync adaptive system Evaluation of SCOOT adaptive system Introduction to OPAC adaptive system

Alpharetta Adaptive Signal Evaluation: Driving Factors Citizens call traffic their #1 issue City Council priority for traffic improvements Bond/Capitol Implementation Funds North Fulton CID project SR 9 Multi-jurisdictional ATMS project

Alpharetta Adaptive Signal Evaluation: Driving Factors SYSTEM BENEFITS (Percent change in) INITIAL CAPITAL COST (per intersection)* Travel TimeDelaysStops ACS-Lite-12% to +7%-38% to +2%-35% to -28%$6,000 to $10,000 OPAC-26% to +10%n/a-55% to 0%$20,000 to $50,000 RHODES-7% to +4%-19% to -2%n/a$30,000 to $50,000 SCATS-20% to 0%-19% to +3%-24% to +5%$25,000 to $30,000 SCOOT-29% to -5%-28% to -2%-32% to -17%$30,000 to $60,000

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

Delay at Traffic Signals Time (years) Delay Do Nothing Periodic Retiming Constant Retiming

Adaptive on Un-Retimed Corridors Time (years) Delay “WOW!!! 30% Improvement!!!” Do Nothing

Adaptive on Retimed Corridors Time (years) Delay Periodic Retiming “We spent how much?”

Savings from Retiming Signals Time (years) Delay Periodic Retiming Constant Retiming

Windward Parkway data is approximate Significant growth in Windward corridor

Windward Parkway 2005 Phase 1 Timings: 17% Reduction in total Delay

Windward Parkway 2007 Phase 2: 7-10% Growth in Midday, PM volumes

Windward Parkway 2007 Phase 2 timings: 11% reduction in total delay

Windward Parkway 2009 Phase 3: Volume growth flat Capacity Improvements- 2 nd WBL lane open at SR9 RTOR allowed at GA 400 ramps

Windward Parkway 2009 Phase 3 timings: 7% reduction in total delay

Windward Parkway Timing Value $2000/day $1.00M/2 yrs $1200/day $0.6M/2 yrs $2500/day $1.25M/2 yrs

Windward Parkway with Adaptive? $2000/day $0.5M/2 yrs $1200/day $0.3M/2 yrs $2500/day $0.6M/2 yrs A = ½ b x h$1.4 M/6 yrs

Alpharetta Adaptive Signal Evaluation: Objectives Prove that system will: – Maintain peak-hour performance – Operate “on-the-fly” – Improve edge-of-peak performance – Provide adequate progression Show that system will: – Adapt to volume changes over time – Adapt for special events – Adapt to unplanned events

Alpharetta Adaptive Signal Evaluation: Metrics Travel time runs Cycle failures Queue failures Cycle lengths Peak hour split percentages System settings

Rhythm InSync Adaptive System Windows based, uses IP communications Video detection- queue density and occupancy Distributed computing- no central server Can phase in by TOD Price $25,000 per intersection Promised 20% improvement

Rhythm InSync Pilot Program Alpharetta responsibilities: – Provide ethernet between signals and VPN – Provide and install ethernet and 14/3 power cable – Provide and install Astrobrac mounts for cameras – Install cameras – Perform before-after studies Rhythm responsibilities: – Provide all hardware and software – Perform on-site installation and configuration

Video Detection

All phases input to controller Controller decides when to start, end phases based on coord plan Traditional Detection

Computer only inputs calls to phases that it wants to have on Ped and preempt calls go to controller and are serviced normally InSync Detection

InSync System Windows server Monitor (optional) Detection output Load switch input Detector cards Pulled out old detection

Controller Setup for InSync Set up detector slots for input Set controller to run free Adjust controller settings – Short minimum times – Short passage time (1.0 seconds) – No recalls or density – No detector switching or delay Optional: install Max 2 times by TOD

Windward Parkway Costco Wal-Mart Home Depot Marriott ADP HP Marconi MARTA Park & Ride HH GreggResidential  Residential  GA 400 North Point Parkway Westside Parkway SR 9 Residential  Lowes KrogerSuper Target, Frys Restaurants and Shops Residential ADT: 40,000

Signal Timing Goals Critical Movements Metered Movements Install InSync PEAK PERIOD GOALS: Preserve critical movements Preserve mainline progression Improve splits for underserved movements on edges of peak

Day 1&2- Off-Peak and AM Computer functions programmed in advance System started up well with limited tweaking “Opportunistic” serving side streets and lefts – Will serve movements when there’s an opening – Followed rules to avoid left-turn traps – Times used were sometimes too short Needed to tweak green bands so as not to short-time side streets and left turns

Day 1 Noon Peak PROBLEMS FOUND: Used 100 s cycle Too fair to side streets Too concerned with green bands

Day 1 PM and Day 2 Noon Locked in 140 s cycle De-prioritized green bands Restricted side streets Still too fair to side streets Not enough progression for NB off-ramp Other progression OK

Day 3 & 4- Reconfiguratoin Wanted to force a “known good” configuration Gave Rhythm existing volumes and timings Set system to mimic existing peak coord plans Allowed system to adjust, using existing coord plans as a basis Better split times throughout peak More time to side streets in beginning of peaks meant less needed in the middle

Pedestrian Problem InSync would be calling phase 7 (SBL) while controller was still clearing phase 6 ped Decided not to run adaptive without accounting for peds Rhythm installed a modification at 2 intersections with the most ped traffic

Final Configuration Restored adaptive within constraints Ran system for several months Cycle length ~10 seconds longer in peaks Split times were appropriate and variable Offsets could not maintain equivalent progression

Windward Travel Time Study

Things I Liked about InSync No controller hardware/firmware changes Elegant handling of vehicle calls Recovers from changes faster than coord plan Good video detection Excellent data display Ability to manually control intersection

Things I Still Want to See Capture and handle pedestrian calls Better constrictions on non-critical movements Automatic notification of problems/disparities – Rhythm working on /text message system Ability to put controller back in coord mode Synchronize coord timer with adjacent signals Opportunity to practice adjusting settings

Rhythm InSync System Evaluation: Objectives Prove that system will: – Maintain peak-hour performance – Improve edge-of-peak performance – Provide adequate progression – Improve off-peak performance Show that system will: – Adapt to volume changes over time – Adapt for special events – Adapt to unplanned events Similar ? ? ? ~ ~

The Verdict- InSync Not seen to handle saturated and over- capacity conditions better than traditional coordination plan Provides a good video detection system, plus monitoring and other functionality Can provide a good traffic responsive system Alpharetta decided to return the equipment and explore other options

Where to Consider InSync Corridors with: – Less-than-saturated conditions – More protected left-turns – Infrequent re-timing – Need for high variation in splits Opportunity to manually manage special events Consider use for video detection, monitoring

SCOOT Adaptive System Marketed by Siemens/Temple 170 installations worldwide 6 installations with about 200 signals in U.S. Centralized computing Ethernet to serial devices to controllers Uses existing Siemens controllers

SCOOT Adaptive System Installed at 5 signals on Old Milton Parkway (SR 120) from Ga 400 to North Point Parkway Most congested corridor in Alpharetta System detection using Sensys – “Pucks” installed in pavement with repeaters – Significantly easier to install than video or loops

Old Milton Parkway GA 400 North Point Parkway Morris Rd Siemens HQ Old Milton/North Point Parkway PM Peak Hour- 7,000+ vehicles Have to give OMP enough time to avoid backing through Ga400 Constricted by short turn bays Ga 400 Interchange Need to keep lefts clear to avoid gridlock on bridge Try to keep ramps out of Ga400 Weave section with Morris Rd

SCOOT Pilot Program Siemens/Temple responsibilities: – Provide all hardware and software – Perform on-site installation and configuration Alpharetta responsibilities: – Install Sensys detection – Perform before-after studies – Assist with timing implementation

SCOOT Pilot Program screenshot

SCOOT Pilot Program screenshot

SCOOT Pilot Program Day 1 of SCOOT control Incident on Ga 400 SB Significant increase of exiting vehicles on SB ramp

SCOOT Pilot Program

SCOOT Experiences Zero complaints from citizens Usually a longer cycle length – SCOOT: 176 seconds in peaks, off-peak – Old plans: in peaks, off-peak System has to include side street ped time (?) Does not handle left-turn trap very well Interface is practically incomprehensible Need better error notification Excellent data storage and organization

Preliminary Before-After Results

Cycle Failures at North Point Pkwy WBLEBLNBLSBLNBTTotal AM Manual32%36%0%8%32%21.6% SCOOT56%12%0%40%4%22.4% Midday Manual36%8%0%12%36%18.4% SCOOT20%32%12%64%16%28.8% PM Manual8%0%52%100%96%51.2% SCOOT32%24%88%100%68%62.4% % of cycles where vehicles do not clear in 1 cycle

SCOOT System Evaluation: Objectives Prove that system will: – Maintain peak-hour performance – Improve edge-of-peak performance – Provide adequate progression – Improve off-peak performance Show that system will: – Adapt to volume changes over time – Adapt for special events – Adapt to unplanned events ? ?

OPAC Marketed by Televent 5 installations with 73 signals in U.S. Distributed computing Ethernet based Uses Econolite controllers Can utilize most of the same detectors as SCOOT

Summary Looking for a system that can provide good signal timing on-the-fly Not expecting a magic bullet to end congestion Expecting benefits on day 300, 500,1000… Expecting benefits on unusual days Trying to investigate all options

*Relative* Costs and Benefits Do Nothing Periodic Retiming Frequent Retiming Traffic Responsive SCATS, SCOOT, OPAC ACS Lite InSync

Questions?