Iteris Systems Template Dark

March 15, 2013
PRESENTATION FOR
Successful Adaptive Control Deployment
Definitions
 What is adaptive traffic control?
 A system that can adjust signal timing by
measuring traffic through detection devices.
 What is “Successful”
 Having obtained something desired or
intended.
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What Do Motorists Want?
• “Why do I have to wait when there’s
nobody else moving”
– Translation: Equitable distribution of green
time
• “Can’t I just drive down the street without
stopping?”
– Translation: Progression—driving through
successive greens
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Traditional Signal Timing
VPH (vehicles per hour)
PEAK 15 Min
4000
3500
3000
2500
2000
1500
1000
500
0
12:00
AM
AM
2:00
AM
4:00
AM
6:00
AM
8:00
AM
10:00 12:00
AM
PM
2:00
PM
4:00
PM
6:00
PM
8:00
PM
10:00
PM
Time of Day
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Variability Is Normal; And the
Problem
PM Peak Period Demand
500
Demand (VPH)
450
SB
400
WBLT
NBLT
350
300NB
EB
WB
250
Time
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Delay
Benefits
Do Nothing
Complaints
Constant Monitoring
& Fine Tuning
Periodic Retiming (Adaptive)
Variability in Demand over time
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Source:
City ofmobility
Alpharetta
Adaptive Benefits
 Improves arterial performance
 Maintains effectiveness of traffic signal timing
 Adapts to seasonal fluctuations in traffic
 Accommodates changes in traffic patterns
 Delivers better service to road users
 Provides progression
 Reduce delay
 Equitable green time distribution
 Traffic incident reaction
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Incident Traffic Congestion
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How Does Adaptive Work?
Communication
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Will Adaptive Work Anywhere?
 Not recommended
 CBD – Closely spaced blocks in a grid layout
 During major detour
 Most corridors can benefit from adaptive
 Congestion on main arterial due to traffic surges
 Delay on crossings due to high cycle length
 Near major traffic generators /unpredictable traffic
• Schools
 Depends on the system
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Before Considering
Adaptive
 Diagnose the traffic problem.
 Can signal timing enhancements fix the problem?
 Is adaptive a realistic solution?
 Are there alternative solutions?
 Support for long-term operation & maintenance?
 Is there staff to monitor the system operation?
 Is there staff to repair failures?
 Who will operate the system?
 What is the desired operation from the system?
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Adaptive Gone Wrong
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Know Your Needs
 Figure out what you want from a system
 What do you want the system to do for you?
 System Requirements formulated from Needs.
 Understand your constraints
 Match traffic needs and goals with available traffic
systems
 Is there a system to fulfill “All” Requirements
 Don’t start selection process from the hardware or
aesthetics
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Know Your Needs
Eastbound Travel
Westbound Travel
SYSTEM ENGINEERING
Tool to help understand our needs and get what
we want from an Adaptive System Control
Technology
15
Eisenhower Wants to Build
Roads
 How fast Germans moved armies
during WWII
 America embroiled in the “Red Scare”
 Post war prosperity presented an
opportunity
2-16
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How Would We Use a New
Roadway Network
 Move armies quickly
 Move people, goods & services
efficiently
2-17
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What slows armies down?
 Intersections
 Narrow roads
 Tight curves
 Incomplete network
2-18
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Basic Requirements
 Limited access
 Wide lanes with shoulders
 Divided highway
 High design speed
 Comprehensive network
2-19
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Functional Requirements
 Highway shall have no at-grade crossings.
 Highway shall separate the two directions of
travel.
 Highway shall accommodate vehicles traveling
at 70 mph.
 Highway shall have 12’ foot lanes.
 Highway shall have vertical clearance of 16.5’.
 Highway shall have maximum grade of 6%.
2-20
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Communication
 Eisenhower doesn’t know anything
about building roads
 Road builders don’t know anything
about moving armies
2-21
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Evaluation
 Did the road get built right?
 Did we build the right roads?
2-22
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Systems Engineering
Process
Testing
Needs
Requirements
Testing
Design & Implementation
2-23
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Systems Engineering
 “An inter-disciplinary approach and
means to enable the realization of
successful systems”
 Focuses on defining customer needs
 Develop required functionality early in the
development cycle
2-24
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Systems Engineering
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System Engineering
Documents
 Concept of Operations
 Focus on Needs
 Requirements
 Mapped to Needs
 Verification
 Ensure system meets Requirements
 Validation
 Ensure system meets Needs
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Example Scenario from
Concept of Operations
Scenario-Typical Non-Peak Period
Operational objectives
The operational objectives for this arterial under these
conditions are to:
 Provide signal timing that prevents phase failures at all
intersections;
 Provide smooth flow along “Arterial” Road.
3-27
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Example Scenario from
Concept of Operations (cont.)
Coordination and signal timing strategies
The signal timing strategies used by the system to
accommodate this situation are:
 At each intersection, provide sufficient time to serve all
turning and side street traffic without phase failures;
 At each intersection, select phase times (or offsets) that
provide smooth flow along the arterial in both directions.
3-28
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Example Scenario from
Concept of Operations (cont.)
Summary of operation
Under these conditions, the ASCT system will determine
reasonable phase times for the each movement to prevent
phase failures. The ASCT will compare volumes and
determine cycle length and offsets which can achieve twoway progression in the case of balanced flows. During
periods (such as lunch time) when there is more turning
traffic associated with local retail activity) extra time will be
provided to those phases within the overall cycle length, at
the expense of the coordinated phases on Aptakisic Road.
3-29
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Example Need Statement from
Concept of Operations (cont.)
Ref. # Concept of Operations Statements
4.1.0- The system operator needs to detect repeated
4
phase failures and control signal timing to prevent
phase failures building up queues. The operator in
this case is trying to prevent a routine queue from
forming where it will block another movement in the
cycle unnecessarily.
For example, the operator may need to prevent a
queue resulting from the trailing end of the through
green from blocking the storage needed by an
entering sidestreet left turn in the subsequent
phase. An overall queue management strategy,
particularly when congestion is present, is covered
3-30
under 4.1.0-1.0-5.
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Model Concept of Operations,
Chapt 8: Operational Needs- Example
The system operator needs the ability to
implement different strategies individually or in
combination to suit different prevailing traffic
conditions. These strategies include:
• Maximize the throughput on coordinated routes
• Provide smooth flow along coordinated routes
• Distribute phase times in an equitable fashion…
3-31
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System Requirement
 “a statement that identifies a necessary
attribute, capability, characteristic, or
quality of a system for it to have value and
utility to a user”
 Based upon ConOps
 Must be verified or measured
3-32
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Model System
Requirements
2.1.1.0-7 The ASCT shall alter the adaptive
operation to achieve required objectives in userspecified conditions.
2.1.1.0-7.0-1 When current measured traffic
conditions meet user-specified criteria, the
ASCT shall alter the state of the signal
controllers, maximizing the throughput of the
coordinated route.
3-33
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Example System
Requirements
System Requirements
Need Statement (Con Ops)
2.1.1.0-9 The ASCT shall detect
repeated phases that do not serve all
waiting vehicles. (These phase failures
may be inferred, such as by detecting
repeated max-out.)
4.1.0-4 The system operator needs to
detect repeated phase failures and
control signal timing to prevent phase
failures building up queues. The
operator in this case is trying to
prevent a routine queue from forming
where it will block another movement
in the cycle unnecessarily.
2.1.1.0-9.0-1 The ASCT shall alter
operations, to minimize repeated
phase failures.
4.1.0-4 The system operator needs to
detect repeated phase failures and
control signal timing to prevent phase
failures building up queues. The
operator in this case is trying to
prevent a routine
queue from forming where it will block
another movement in the cycle
3-34
unnecessarily.
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Benefits of Systems
Engineering
 Reduced risk of schedule and cost
overruns
 Verified functionality and fewer defects
 Better documentation
 Increased likelihood that implementation
will meet users’ needs
 Ensures you “get what you need”
2-35
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Washington DC - Adaptive
 Corridor Selection
 6 corridors evaluated
 Selected 3 for pilot
project
 Identified corridor limits
 Evaluated 16 Adaptive
Systems
 Identified 4 systems for
detailed review
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Important Considerations
Agency
Resources
• Operational
Objectives and
Philosophy
• Operations and
Maintenance
• Staff skills and
abilities
• Funding Sources
Site Suitability
• Arterial v. grid
• Emerging
congestion
• Traditional
objectives
unattainable
• Traditional
methods failed
System Cost
•
•
•
•
Capital Cost
Operations
Maintenance
Staff Training
Existing
Infrastructure
• Closed loop vs
Centrally
managed
• Communications
• Sensor hardware
• Overall system
reliability
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New York Avenue – Virtual
Circle
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New York Avenue – Traffic
Data
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Selecting Adaptive Systems
Categorization
Function/Capability/Software/Hardware
Required
ACS-Lite
Stop-line (SL), Mid-block (MB) /
Upstream (US)
Naztec Streetwise (ATMS)
Stop-line (SL), Upstream (US)
McCain QuicTracTM
Mid-block (MB) & Stop-line (SL)
SYNCHRO Green
Stop-line (SL) & Advanced Detection (200500 ft upstream of stop bar)
BALANCE
Near-stop-line (NSL)
INSYNC
Stop-line (SL), Near-stop-line (NSL)
LA ATCS
Advanced Detection (200-400 ft
upstream of stop bar)
Detector Type
Optional
Action
Proactive & Reactive
Proactive & Reactive
Proactive & Reactive
Proactive & Reactive
Proactive & Reactive
Real-time adaptive
Proactive & Reactive & Simple
Predictive
Adjustment
Time-constrained optimization
Rule-based adjustment
Domain-constrained optimization
Rule-based adjustment
Time-constrained optimization
Rule-based adjustment, Timeconstrained optimization
Data based adjustment, Domainconstrained optimization
Time-Frame
OPERATIONAL
Stop-line (SL)
5-15 min
Cycle
Cycle
Cycle
5 min
sec by sec
Cycle
Level
Local & Central
Local & Central
Local & Central
Local & Central
Local & Central
Global & Local
Local & Central
Model
No
No
Yes
Yes
Yes
Yes
No
Splits, Offset
Splits, Cycle, Offset
Splits, Cycle, Offset, Phase sequencing
Splits, Cycle, Offset
Splits, Cycle, Offset, Phase
sequencing
Period, Duration, Offset
Splits, Cycle, Offset
Flex Region
No
No
No
No
No
Yes
Yes
Vehicle Actuated
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Transit Signal Priority (TSP)
Yes
Not Available
Yes
Yes
Yes
Yes
Yes
CORSIM
No
No
SimTraffic
NONSTOP, VISSIM
VISSIM, Insync Sim
CORSIM(Offline post-processing
interface)
Centralized & Distributed
Centralized
Hierarchical
Centralized
Centralized
Fully Distributed - Decentralized
Centralized
No. of Installations
15
<10
2
1
Not available
47
3
No. of Intersections operating with adaptive
100
Not Available
80
12
Not available
303
> 3000
Vendor estimated
Cost per intersections
≤ $ 25,000
≤ $ 10,000
≤ $ 15,000
≤ $ 25,000
Not available
≤ $ 25,000
≤ $ 15,000
Estimate Cost (12 Intersection) excluding controllers & Comm. upgrades
& Construction
$168,000
Not Available
$188,000
Not available
$476,000
$115,000
Timings
Interfaces
Communication Architecture
With existing QuicNet in DC, actual cost is
$168,000
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Douglas Park – Adaptive Project
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Douglas Park - SE Process
 Implement one single adaptive traffic control system
 Provide for data exchange amongst agencies/operators to
provide regional coordination
 Adapt to traffic signal operations & congestion across
jurisdictions
 Be able to relinquish control if so desired
 Enable multi-jurisdictional coordinated response to incidents
& special events
 Compatible with Long Beach transit systems
 Light Rail Train Operations
 Transit Priority Systems
 Event Management
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Results
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Time-Space Diagram - Willow
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Questions
Gabe Murillo,
Associate Vice President
1700 Carnegie Ave, Suite 100
Santa Ana, CA 92705-5551
Phone: (949) 270 - 9582
E-Mail: [email protected]