T3 Webinar Presentation

Keeping Risks in Check: Applying the Updated FHWA Model Systems Engineering Document to Adaptive Signal Control Technology (ASCT) Implementation (December 20, 2012)

Presenter:   Richard W. Denney, Jr.
Presenter's Org:   FHWA Resource Center (Baltimore, MD)

HTML version of the presentation
Image descriptions are contained in brackets. [ ]
Back to Webinar Files

T3 Webinars are brought to you by the ITS Professional Capacity Building (PCB) Program at the U.S. Department of Transportation's (USDOT) ITS Joint Program Office (JPO), Research and Innovative Technology Administration (RITA).


Many of the slides in this presentation display the Every Day Counts logo.

Slide 1:  Adaptive Signal Control Technology Model Systems Engineering Documents

December 20, 2012

U. S. Department of Transportation
Federal Highway Administration

Slide 2:  What Do Motorists Want?

Slide 3:  The Big Box Scenario – Year 1

[This slide contains a map of an area with an arterial street crossing a highway with residential neighborhoods on the edges in Year 1. Traffic signal graphics indicate intersections with signals. A red circle represents a Big Box store in the area.]

Slide 4:  TYPICAL Traffic Signal Timing

[This slide contains a graph that demonstrates typical traffic signal timing with Vehicles per Hour on the Y axis and Time of Day on the X axis. There are peaks at approximately 8:30 AM and 4:30 PM. A thin black line represents traffic volume collected when traffic signal timing is implemented. A thick black line represents projected volumes. A pink line represents data collected to design an AM timing plan, typically collected 1 day out of the year and designed to accommodate the peak 15 minutes. A red line illustrates the change in traffic conditions often deviating from the conditions for which the timing was designed, resulting in delays. A blue line represents an AM peak plan that last from 5:00 AM to 10:30 AM. White lines represent other plans used throughout the day. Yellow ovals represent periods where signal timing plans can be improved.]

Slide 5:  Year 9

[This slide contains the previous map of an area with an arterial street crossing a highway with residential neighborhoods on the edges. This map demonstrates the growth of businesses in the area and additional traffic signals in year 9. Traffic signal graphics indicate intersections with signals. Red circles represent Big Box stores and other business establishments in the congested area.]

Slide 6:  Year 10

[This slide contains the previous map of an area with an arterial street crossing a highway with residential neighborhoods on the edges. This map demonstrates the growth of businesses in the area and additional traffic signals in year 10. Traffic signal graphics indicate intersections with signals. Red circles represent Big Box stores and other business establishments in the congested area.]

Slide 7:  Variability is Normal—And the Problem

[This slide contains a graph that demonstrates how the variability of traffic is normal and also presents a problem for signal timing. The graph is comprised of the Demand/Vehicles per Hour on the Y axis and Time of Day on the X axis. A red line represents the southbound movement. An aqua line represents the northbound left turn movement. A yellow line represents the westbound traffic movement. A pink line represents the westbound left turn traffic movements. A purple line represents the northbound movement. A blue line represents the eastbound movement. A yellow rectangular shaded area represents how competing movements of southbound and northbound left turn traffic receive green lights for different periods of time during a 15 minute peak between 5:15 PM and 5:30 PM. A yellow circular shaded area represents the peak of the northbound left turn movements an hour later.]

Slide 8:  Year 13

[This slide contains the previous map of an area with an arterial street crossing a highway with residential neighborhoods on the edges. This map demonstrates the growth of businesses in the area and additional traffic signals in year 13. Traffic signal graphics indicate intersections with signals. Red circles represent Big Box stores and other business establishments in the congested area. There are more traffic signals closer together and the signal spacing is unfavorable compared to previous years' maps.]

Slide 9:  Adaptive Signal Control Technology

[This slide contains two graphics representing the signal timing process. The left graphic consists of five steps involved in traditionally developing signal timing: 1) Trigger Event; 2) Data Collection; 3) Modeling/Optimizations; 4) Implement & Fine Tune; and 5) Reporting. On the right is a graphic of three steps that represent the Adaptive Signal Control Technology process: 1) Monitor Traffic; 2) Evaluate Performance; and 3) Update Timing. This Adaptive Signal Control Technology process is shorter and quicker than the five traditional steps; it also incorporates each task of the conventional method.]

Slide 10:  Getting It Right is Important

Slide 11:  23 CFR 940.11 Requirements

Slide 12:  Seven Requirements of SE Analysis

  1. Identify portions of the regional ITS architecture being implemented
  2. Identification of participating agencies roles and responsibilities
  3. Requirements definitions
  4. Analysis of technology options to meet requirements
  5. Procurement options
  6. Identification of applicable ITS standards and testing procedures
  7. Procedures and resources necessary for operations and management of the system

Slide 13:  Procurement Regulations

Slide 14:  What is Commercial-Off-The-Shelf (COTS)?

Slide 15:  Typical Procurement

[This slide contains three procurement process flow diagrams. The bottom and second approaches contain the following steps: conduct market research for product, design Plans, Specifications & Estimates (PS&E), receive bids, make product selection based on cost, approve contractor's material submittal, construction begins, and finally accept the project. The last approach, called Consumer Reports/Low Bid, is highlighted on this slide. In this process, the project requirements are discovered after construction. The first two approaches are called Low Bid Supported by SE Analysis and Best Value Supported by SE Analysis. Both processes are informed by the Systems Engineering analysis. The Low Bid Supported by SE Analysis approach contains the same steps listed above and the requirements for the project are provided at the PS&E, Submittal, and Acceptance stages of the procurement process. The top approach to procurement is called Best Value Supported by SE Analysis and contains the following steps: submit request for proposal, review proposal, make a selection based on how requirements are being fulfilled, evaluate progress during implementation, and finally use the requirements for acceptance testing. The requirements for the project are provided throughout the procurement process.]

Slide 16:  Model Systems Engineering Document for ASCT Systems

[This slide contains a picture of the cover of the Model Systems Engineering Document for ASCT Systems.]

Slide 17:  Purpose of SE Model Documents

Slide 18:  Model Document Process

Build Requirements

  • Answer questions
    • About the situation
    • About you
  • Select and tailor ConOps statements
  • Select and tailor requirements

Evaluate Alternatives

  • Evaluate proposed approaches/products against requirements
  • Solution feasible given constraints?

Continue Tailoring Until Solutions…

  • Fulfill requirements
  • Are feasible

[This slide contains a flow diagram of the Model Systems Engineering Document for ASCT Systems process aligned across an arrow pointing to the right. The process is demonstrated by displaying the three steps in separate boxes along the arrow. The first step is to build requirements for proposed ASCT project. The second step is to evaluate alternatives based on requirements. The process ends with continuing to tailor requirements, if necessary, until requirements are fulfilled and feasible. The details of the three steps are listed above.]

Slide 19:  Model Document Products

Concept of Operations: What You Need

  • Basis for creating and defending requirements
  • Basis for validating system

Well-Formed, Testable Requirements Driven by Needs

  • Basis for product choices
  • Basis for procurement documents
  • Basis for verification of design and installation: testing and acceptance

Sample project architecture

  • Basis for achieving integrated traffic management systems

[This slide contains a diagram of the products of the Model Systems Engineering Document for ASCT Systems process. The three products are displayed in three separate boxes. The first product is the Concept of Operations, which defines what is needed. The second product is a Well-Formed, Testable Requirements Driven by Needs. The final product is a Sample Project Architecture. The details of these three products are listed above.]

Slide 20:  Outcome of the Process

Slide 21:  SE-Informed Procurement

[This slide contains a flow diagram of three procurement processes. The bottom and second approaches contain the following steps: conduct market research for product, design Plans, Specifications & Estimates (PS&E), receive bids, make product selection based on cost, approve contractors' materials submittals, construction begins, and finally accept the project. The last approach is called Consumer Reports/Low Bid. In this process, the project requirements are discovered after construction. The first two approaches to procurement are highlighted on this slide and are called Low Bid Supported by SE Analysis and Best Value Supported by SE Analysis. Both processes are informed by the Systems Engineering analysis. The Low Bid Supported by SE Analysis approach contains the same steps listed above and the requirements for the project are provided at the PS&E, Submittal, and Acceptance stages of the procurement process. The top approach to procurement is called Best Value Supported by SE Analysis and contains the following steps: submit request for proposal, review proposal, make a selection based on how requirements are being fulfilled, evaluate progress during implementation, and finally use the requirements for acceptance testing. The requirements for the project are provided throughout the procurement process.]

Slide 22:  Guidance Document Organization

Slide 23:  Concept of Operations Organization

  1. Scope
  2. Referenced Documents
  3. User-Oriented Operational Description
  4. Operational Needs
  5. Envisioned Adaptive Operation
  6. Adaptive Operational Environment
  7. Adaptive Support Environment
  8. Proposed Operational Scenarios

Slide 24:  3. User-Oriented Operational Description

3 3 Chapter 3: User-Oriented Operational Description
3.1 3.1 The Existing Situation
3.1.1 3.1.1 Network Characteristics
3.1.1.1 3.1.1.1 Arterial
3.1.1.1.0-1 The arterial has regularly spaced signalized intersections. The spacing between major intersections is approximately XX, with less important intersections spaced at XX. The locations at which ASCT is being considered are illustrated in FIGURE XX.
3.1.1.1.0-2 The free-flow travel time between major intersections is approximately XX seconds. (Expand this description as appropriate to cover additional arterials or networks.)
3.1.1.1.0-3 The travel time between key intersections allows two-way progression when cycle lengths (CL) of XX seconds (CL= travel time) or YY (CL= 2x travel time) seconds can be used. (Add descriptions of additional cycle lengths if appropriate.)
3.1.1.1.0-4 The arterial has irregularly spaced signalized intersections, and there is no “natural” cycle length that allows two-way progression.
3.1.1.1.0-5 During the peak periods, the cycle length is generally determined by the needs of one or more critical intersections.
3.1.1.1.0-6 The cycle length required to service traffic at the critical intersection(s) is generally close to a “natural” cycle length.
3.1.1.1.0-7 The capacity of the arterial changes during the day, with parking restrictions providing higher capacity during peak periods.
  AND SO ON…

[This table is from Chapter 3 of the Model Systems Engineering Document for ASCT Systems and is titled User-Oriented Operational Description.]

Slide 25:  4. User Needs

Con Ops Reference Number Concept of Operations Sample Statements System Requirements (Tailor as required - See Guidance) Guidance Section
4 4 Chapter 4: Operational Needs    
4.0-1 This chapter describes the operational needs of the users that should be satisfied by the proposed ASCT system. Each of these statements describes something that the system operators need to be able to achieve. Each of these needs will be satisfied by compliance with one or more system requirements. In the attached list of requirements, each one is linked to one or more of these needs statements.    

[This table is from Chapter 4 of the Model Systems Engineering Document for ASCT Systems and is titled User Needs.]

Slide 26: 

4.1 4.1 Adaptive Strategies    
4.1.0-1 The system operator needs the ability to implement different strategies individually or in combination to suit different prevailing traffic conditions. These strategies include:   3.4

3.5

4.1.0-1.0-1 *Maximize the throughput on coordinated routes

Note to user when selecting these requirements:

Select from requirements in the 2.2 group when sequence-based systems are allowed (sequence-based systems explicitly calculate cycle, offset, and split).

Select from requirements in the 2.3 group when non-sequence-based systems are allowed (non-sequence-based systems do not explicitly calculate cycle, offset, and split).

(Select requirements from both groups when the vendor is given the choice of supplying one type of adaptive operation or the other.)

2.2.0-4

2.2.0-4
(Sequence-based only) The ASCT shall calculate offsets to suit the current coordination strategy for the user-specified reference point for each signal controller along a coordinated route within a group.

2.2.0-4.0-1
(Sequence-based only) The ASCT shall apply offsets for the user-specified reference point of each signal controller along a coordinated route.

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.

3.4

3.5

[This table is from Chapter 4 of the Model Systems Engineering Document for ASCT Systems and details Adaptive Strategies.]

Slide 27:  (No Title)

4.1.0-5 The system operator needs to minimize the chance that a queue forms at a specified location.

Note to user when selecting these requirements:

Select from requirements in the 2.2 group when sequence-based systems are allowed (sequence-based systems explicitly calculate cycle, offset, and split).

Select from requirements in the 2.3 group when non-sequence-based systems are allowed (non-sequence-based systems do not explicitly calculate cycle, offset, and split).

Select from requirements in the 2.5 group when phase-based systems are allowed (phase-based systems do not explicitly calculate cycle, offset and split at all intersections).

(Select requirements from two or all three groups when the vendor is given the choice of supplying the type of adaptive operation.)

2.3.0-5
(Non-sequence-based only) The ASCT shall adjust signal timing so that vehicles approaching a signal that have been served during a user-specified phase at an upstream signal do not stop.

2.5.0-7
(Phase-based only) The ASCT shall adjust the state of the signal controller so that vehicles approaching a signal that have been served during a user-specified phase at an upstream signal do not stop.

2.2.0-5.0-5
(Sequence-based only) The ASCT shall adjust offsets to minimize the chance of stopping vehicles approaching a signal that have been served by a user-specified phase at an upstream signal.

3.4

3.5

[This table is from Chapter 4 of the Model Systems Engineering Document for ASCT Systems and details Adaptive Strategies.]

Slide 28:  (No Title)

4.14.0-1 The system operator needs to fall back to TOD or isolated free operation, as specified by the operator, without causing disruption to traffic flow, in the event of equipment, communications and software failure.

13.1.0-2
The ASCT shall use the following alternate data sources for operations in the absence of the real-time data from a detector:

13.1.0-2.0-3
The ASCT shall switch to the alternate source in real time without operator intervention.

13.1.0-1
The ASCT shall take user-specified action in the absence of valid detector data from XX vehicle detectors within a group. (SELECT THE APPROPRIATE ACTION.)

13.1.0-1.0-1
The ASCT shall release control to central system control.

13.2-1
The ASCT shall execute user-specified actions when communications to one or more signal controllers fails within a group. (SELECT THE APPROPRIATE ACTION)

…(snippage)…
13.3-4
During adaptive processor failure, the ASCT shall provide all local detector inputs to the local controller.

4.13

[This table is from Chapter 4 of the Model Systems Engineering Document for ASCT Systems and details Adaptive Strategies.]

Slide 29:  Basic Systems Engineering Deliverables

Slide 30:  Requirements Before Design

[This slide contains three procurement process flow diagrams. The bottom and second approaches contain the following steps: conduct market research for product, design Plans, Specifications & Estimates (PS&E), receive bids, make product selection based on cost, approve contractor's material submittal, construction begins, and finally accept the project. The last approach is called Consumer Reports/Low Bid. In this process, the project requirements are discovered after construction. The first two approaches to procurement are highlighted on this slide and are called Low Bid Supported by SE Analysis and Best Value Supported by SE Analysis. Both processes are informed by the Systems Engineering analysis. The Low Bid Supported by SE Analysis approach contains the same steps listed above and the requirements for the project are provided at the PS&E, Submittal, and Acceptance stages of the procurement process. The top approach to procurement is called Best Value Supported by SE Analysis and contains the following steps: submit request for proposal, review proposal, make a selection based on how requirements are being fulfilled, evaluate progress during implementation, and finally use the requirements for acceptance testing. The requirements for the project are provided throughout the procurement process.]

Slide 31:  Model SE Documents for ASCT (Final)—Now Online

http://ops.fhwa.dot.gov/publications/fhwahop11027/index.htm

Slide 32:  Questions?

http://www.fhwa.dot.gov/everydaycounts

Rick Denney, P.E.
FHWA Resource Center
Traffic Management Specialist
(410) 962-4796
Richard.Denney@ dot.gov

Paul R. Olson, P.E.
FHWA Resource Center
Traffic Management Specialist
(720) 963-3239
Paul.Olson@dot.gov

Eddie Curtis, P.E.
FHWA Resource Center
Traffic Management Specialist
(404) 562-3920
Eddie.Curtis@dot.gov


Back to Top