Traffic Controller--Intersection-Simulation Board
Sponsor Information:

The sponsor is AZTrans: The Arizona Laboratory for Applied Transportation Research. The client contact is Craig Roberts. Since Dr. Roberts is a NAU faculty member, the student design team will have easy access on a timely basis whenever it is needed. The sponsor will demonstrate all of the hardware and software programming and make it available to the team, as required, for their work. The sponsor will pay all reasonable costs of development, including frequent pizza for late-night sessions. For additional information and a view of the equipment to be simulated contact:

Craig Roberts, Ph.D., P.E.
Room 241 CET Building
Phone 928.523.0651
email: craig.roberts@nau.edu
web: www.cse.nau.edu/~car3

Project Overview:

Use of Traffic Controller in Industry
The Traffic Controller is the backbone of the traffic signalization of an intersection. The controller contains a microprocessor integrated with various electrical components that work together to receive inputs (sensors in pavements that detect vehicles), apply programmed logic, and send outputs (actuate control circuits that engage relays that energize specified indicators in the traffic light faces in the intersection). The programming of the controller is the heart of signal timing. Timing plans are developed using traffic data collected in the field. The controller is programmed to reflect the desired plan, which is always specific to the intersection. In more complex situations, an integrated timing plan is developed for a specific series of intersections acting together to efficiently move traffic through them as a group.

Use of the Traffic Controller in teaching of traffic engineering
The use and programming of a Traffic Controller in a student lab situation is one of the fundamental leaps from the theory of traffic engineering taught in the classroom to the actual implementation of the theory in real-world situations by practicing engineers. It is considered critical to the teaching of traffic engineering at NAU. It is implemented at NAU by attaching the controller to an intersection-simulation board that allows the student to test his/her timing plans under the actual conditions encountered in typical field installations. In the figure, the bottom box is the traffic controller and the top "birds-eye" view of an intersection is the intersection-simulation board. NAU is currently developing a Masters of Engineering (MEng) program as part of a tri-university consortium: NAU, ASU, and U of A (http://triuniv.engr.arizona.edu/). The MEng degree will be completely web-delivered. The transportation track (http://triuniv.engr.arizona.edu/curricular/transportation.html) is a group of specialized courses that are taken by a student interested in this focus. The programming of a timing plan into the traffic controller and the testing of the plan using an intersection-simulation board is considered critical to the success of teaching traffic engineering courses for the MEng.

Scope of Work
The goal of the work is to provide the "Traffic Controller--Intersection-Simulation Board" programming and timing plan testing experience to students taking traffic engineering courses via the web.

Simulation at a student's computer of the "Traffic Controller--Intersection-Simulation Board" experience: The concept is that the student will be able to use his/her computer to a) program the traffic controller with his/her timing plan and b) then test his/her timing plan using a fully functional Intersection-Simulation board displayed in his/her monitor. These functions will be machine (OS) independent. The student will program his/her signal timing plan in the simulated Traffic Controller from his/her local computer. This is done by specifying a group of values for each traffic movement in the intersection (e.g., Northbound Left-Turn (NB LT)). Then the student will be able to test his/her timing plan on an Intersection-Simulation Board that will be created on his/her screen. The board has input buttons on the various traffic lanes leading to the intersections, which simulates the passing of a vehicle over a vehicle detection device. This creates an input signal to the traffic controller. Based on the logic contained in the student loaded timing plan, the traffic controller reacts to the inputs by changing the signals for various movements (e.g., it changes the NB LT to a yellow, then changes it to a red, then changes the Southbound Through (SB TH) light to a green).

The traffic controller has built-in logic and logic that is changed by the student's programming of his/her timing plan. Both of these logics will function in the simulation. All of these functions relate and display to real-time with an accuracy of 0.1 seconds.
Prerequisites:

Traffic Engineering Skills/Knowledge: Rudimentary knowledge of how a traffic signal controller works is required. However, the concepts needed for this project are straightforward and quickly learned. The sponsor will provide a complete briefing and will be available throughout the project to answer questions at any time. Whereas the levels of logic employed by the signal controller can be very sophisticated, typical applications only use a few of the basic logic levels. Reproducing these basic levels is all that is desired for this project. Several controller operating manuals and supplemental texts are available for the team's reference. At least two controller manufacturers support educational uses of their equipment and can also be consulted, if needed.

Computer Science/Engineering Skills/Knowledge: The sponsor cannot identify the specific skills and knowledge the team will require to accomplish this project. It is assumed that the description of the project and its objectives will allow the team to decide this question for themselves. Additionally, Dr. Doerry has been completely briefed on this project and can be consulted for any additional information needed.
Equipment Requirements:

A complete "Traffic Controller--Intersection-Simulation Board" (as shown in the figure) will be available at essentially all times for the team's use. It is this physical set-up that the team will be simulating. The team will use NAU CSE's computing resources to accomplish the project. It is not anticipated that any additional CSE resources will be required, but the sponsor will work with the team to acquire a special resource if one is identified.
Deliverables:

The team will be expected to propose and deliver:

  • Simulation at a student's computer of the "Traffic Controller--Intersection-Simulation Board" experience: An acceptable solution in the form of a machine/OS independent "software package" (may be the incorrect CSE term) will be delivered. The package ideally will be "downloaded" (may be incorrect CSE term) from the teacher's web site and used by the student while "offline" (may be incorrect CSE term) at his/her computer. Alternatively, the student could be required to use it "online." Deciding on the best approach is part of the solution desired from the team.
    The overarching goal is to allow a student to develop a signal timing program and test it using the team's deliverables, herein simply called a "computer-simulator." So, while using the computer-simulator, the student will be able to a) input a timing plan to the simulation either from his/her local keyboard or through a pre-prepared input file, b) "push buttons" on the computer-simulated intersection board, which is displayed on their monitor, that provide inputs indicating that vehicles have crossed vehicle detectors in specific lanes, and c) watch the responses of the computer-simulated intersection signal lights to these inputs. All of this occurs in real-time to an accuracy of 0.1 seconds.
    Additionally the controller's monitoring data that is shown on a real controller's LED display will be created and shown on the computer's monitor simultaneously with the computer-simulated intersection graphics. This information is simply a digital form of what will be occurring graphically on the monitor. Documentation will be created of the student's timing plan and testing session, which will be downloaded as a file at the end of the session to the student's local computer for his/her later review.
    Alternate methods to those described above that fulfill the objectives are also acceptable.
  • Beta testing by a traffic engineering class: The traffic engineering class that will be using the deliverables of this project will be taught in the Spring 2002 semester, which is the same time period as the team will be developing the deliverables. Ideally this class can be used to beta test various components as they are developed and refined.

All software must be extremely well documented with a) numerous comments within the code (for later upgrades by others) and b) in a written document (for later upgrades and installation of software by the maintainers of various servers). Electronic delivery of all documentation in PDF or Microsoft Word is preferred.