U.S. DEPARTMENT OF TRANSPORTATION

CAFE Model Software Manual

Introduction

This document provides an overview of the CAFE Model software. It is intended as a guide to familiarize new users with the runtime features available in the modeling system. The detailed discussion of the modeling logic, economic and vehicle technology assumptions, as well as modeling inputs and outputs are beyond the scope of this document. For more detailed information on the CAFE Model, please refer to the CAFE Model Documentation.

Table of Contents

Introduction. i

Table of Contents. i

Warnings. 1

Notice. 1

Installation and System Requirements. 1

CAFE Model Graphical User Interface. 2

CAFE Model Window.. 3

Modeling Settings Window.. 5

General Compliance Settings Panel 5

Input Settings Panel 6

Output Settings Panel 8

Runtime Settings Panel 10

CAFE Model Usage Examples. 11

Example 1 – Configuring for Standard Compliance Modeling. 11

Example 2 – Configuring for Monte-Carlo Modeling. 20

Warnings

This software was developed for analysis by U.S. Department of Transportation staff of potential fuel economy requirements.

This software uses input files containing detailed information regarding vehicles manufactured for sale in the United States and creates output files containing similarly detailed information regarding such vehicles. If input files containing information in any way (e.g., based on entitlement under 5 U.S.C 552 to confidential treatment) protected from disclosure to the public are used, some output files created by this software must also be protected from disclosure to the public.

Notice

The CAFE Model software is a U.S. government work not subject to copyright pursuant to 17 USC 105; however, some of the third-party works used by the software are subject to usage agreements, as described below.

The button controls in the application toolbar of the CAFE Model use images from the Glaze Icon Set (version 0.4.6, released on 3/06/2006) obtained from http://www.notmart.org. All icons and/or images within the Glaze Icon Set are distributed under the GNU Lesser General Public License (LGPL), version 2.1. The version 2.1 of the GNU LGPL may be obtained from http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

If users of the CAFE model have any questions about this notice, please contact the current administrators of the CAFE Model project.

Installation and System Requirements

The CAFE Model runs on IBM-compatible computers using the Microsoft® Windows operating system. Although the software does not have strict hardware requirements, beyond what is needed to run the operating system, a 1 GHz or faster Intel compatible processor, with at least 2 GB of physical memory (RAM) is strongly recommended. The software has been developed and tested on computers using Windows XP/7 and Windows Server 2003/2008, but may operate properly on machines using older versions of Windows (e.g., Windows 2000), or newer versions (e.g., Windows 8), as long as a compatible Microsoft® .NET Framework is installed.

The CAFE Model software uses Microsoft® Excel to read input files needed for modeling. As such, Excel must be installed on the system. The software also uses the Microsoft® .NET Framework, version 3.5. If the Framework is not already present, it must be installed. Instructions for downloading and installing the .NET framework are available on the Internet at http://www.microsoft.com/download/en/details.aspx?id=22.

Based on the characteristics of machines used in the development of this software, the following table provides a summary of system requirements:

Table 1. CAFE Model System Requirements

Intel compatible processor (1 GHz or faster recommended)
1 GB RAM (2 GB recommended)
10 MB hard drive space for installation (additional disk space will be required during runtime)
Microsoft® Windows XP/Vista/7/8 Microsoft® Windows Server 2003/2008
Microsoft® .NET Framework 3.5
Microsoft® Excel 2010 or later

Once the system requirements have been met, the latest version of the CAFE Model may be obtained by contacting NHTSA or Volpe Center staff.

The current version of the software is packaged as a stand-alone executable and does not require installation. To operate the model, place the “CAFE Model.exe” file on the desktop and execute it[1].

CAFE Model Graphical User Interface

The CAFE Model Graphical User Interface (GUI) provides users with a set of tools necessary to set up and run multiple modeling test scenarios, which are commonly referred to as CAFE Model sessions. Each CAFE Model session can be configured independently, each with its own set of model inputs and settings. Once configured, the session may be saved for future runs, or executed immediately.[2] When the model runs, the system displays the progress of the compliance modeling process in each session’s window.

The model GUI consists of two primary screens: the main CAFE Model window and the Modeling Settings window. The CAFE Model window is used for managing the modeling sessions, while the Modeling Settings window is used to configure them.

To run the modeling system, click on the CAFE Model executable file located on the desktop. When the application launches, a Warnings dialog box is displayed (Figure 1). The user must read and understand the warnings listed prior to using the modeling system.

Figure 1. Warnings Dialog Box

After clicking the OK button in the Warnings dialog box, the main CAFE Model window, described below, opens.

CAFE Model Window

The main CAFE Model window (Figure 2) is used to create, configure, and manage CAFE modeling sessions. The main window also controls the model operation, allowing users to start and stop modeling simulation.

Figure 2. CAFE Model Window

When the model first starts up, most of the menu items and toolbar icons are disabled, until a new session is created, or an existing one is opened.

The model GUI is operated using a simple, easy to use file-menu (Figure 3), with most commonly used shortcuts also available on the model toolbar (Figure 4). For user convenience, most of the menu entries may also be controlled using keyboard shortcuts.

Figure 3. CAFE Model File Menu

Figure 4. CAFE Model Toolbar

Some of the most commonly used file menus are:

· File > New Session: Creates a new CAFE Model Session and displays the Modeling Settings window to the user.

· File > Open Session: Opens an existing CAFE Model Session.

· File > Close Session: Closes the active CAFE Model Session.

· File > Save Session: Saves the active CAFE Model Session.

· File > Start Modeling: Begins the modeling process for the active CAFE Model Session.

· File > Stop Modeling: Suspends the modeling process of the active CAFE Model Session.

· File > Exit: Exits the CAFE Model. If any of the modeling sessions are still opened, they will be closed prior to exiting the model.

· View > Modeling Settings: Displays the Modeling Settings window, where all modeling options and settings may be configured.

· View > Output Location: Opens the Windows Explorer and browses to the location where the output files and reports of the active session are saved.

Modeling Settings Window

The Modeling Settings window contains multiple panels for configuring all of the runtime options available to the model. The user can operate this window to set up a new session, or modifying an existing one, before starting the modeling process. Each of the available configuration panels is outlined in the sections below.

General Compliance Settings Panel

The General Compliance Settings panel (Figure 5) is used to specify what type of modeling the user would like to run. Each model is tailored to different type of analysis, using its own set of assumptions and configuration settings. Presently, two model types are available:

· Standard Compliance Model: The Standard Compliance Model is the default mode of operation for the CAFE modeling system. This model type is used to evaluate technology costs and benefits in response to the required CAFE standards defined in the modeling scenarios.

· Monte-Carlo Model: The Monte-Carlo Model is a specialized CAFE modeling type, which is used for running customized Monte-Carlo simulations necessary for uncertainty analysis.

Figure 5. General Compliance Settings Panel

Input Settings Panel

On the Input Settings panel (Figure 6), the user can select the input data files for use with the modeling system.

Figure 6. Input Settings Panel (1)

When selecting input files, the model will attempt to verify if an appropriate file was used. If incorrect file path is entered, an error message will be displayed (Figure 7).

Figure 7. Input Settings Panel (2)

Output Settings Panel

The Output Settings panel (Figure 8) is used to configure the location where modeling results will be saved.

Figure 8. Output Settings Panel

The modeling system automatically generates the following eight output files (in CSV format) during runtime:

· Technology Utilization Report: Provides manufacturer-level and industry-wide technology application and penetration rates for each technology, model year, and scenario analyzed. The results are disaggregated by regulatory class, as well as combined over the entire fleet.

· Compliance Report: Provides manufacturer-level and industry-wide summary of compliance model results for each model year and scenario analyzed. The results are disaggregated by regulatory class, as well as combined over the entire fleet.

· Societal Effects Report: Provides industry-wide summary of energy and emissions effects for each model year and scenario analyzed. The model produces two versions of this output file, where the results are disaggregated by either the vehicle class and fuel type or the regulatory class and fuel type, as well as combined across all fuels and over the entire fleet.

· Societal Costs Report: Provides industry-wide summary of consumer and social costs for each model year and scenario analyzed. The model produces two versions of this output file, where the results are disaggregated by either the vehicle class and fuel type or the regulatory class and fuel type, as well as combined across all fuels and over the entire fleet.

· Annual Societal Effects Report: This output file is similar to the Societal Effects Report, except it further disaggregates the results by calendar year.

· Annual Societal Costs Report: This output file is similar to the Societal Costs Report, except it further disaggregates the results by calendar year.

· Vehicles Report: Provides a detailed view of the final state of each vehicle examined by the model, for each model year and scenario analyzed.

Runtime Settings Panel

The Runtime Settings panel (Figure 9) provides additional modeling options to further customize the model behavior, beyond what is available in the input files:

· Fuel Price Estimates: Specifies whether to use the low, average, or high fuel price estimates from the parameters input file. By default, average fuel price estimates are used.

· CO2 Price Estimates: Specifies whether to use low, average, high, or very-high carbon dioxide cost estimates from the parameters input file. By default, average CO2 price estimates are used.

· Scale Consumer Benefits: Specifies whether the model should scale the private consumer benefits by a specific percentage during the effects calculations. Valid values are between 0 and 100.

· Perform Fleet Analysis Calculations: Specifies whether the model should perform fleet analysis calculations, evaluating modeling effects for historic and forecast model years (before the first compliance model year as well as after the last compliance model year).

Figure 9. Runtime Settings Panel

CAFE Model Usage Examples

This section provides examples for configuring and running the CAFE Model sessions using various model types.

Example 1 – Configuring for Standard Compliance Modeling

This example demonstrates the steps necessary for configuring the modeling system to perform a regular Compliance Model run.

· Run the CAFE Model by clicking on the CAFE Model executable located on the desktop. Read through the Warnings dialog box, and then click the OK button.

· Select File > New Session to create a new modeling session. The Modeling Settings window appears. Note the errors at the bottom of the window; these indicate that the input files have not been selected.

· On the General Compliance Settings panel, select the Standard Compliance Model as shown in Figure 10 below.

Figure 10. Select Standard Compliance Model

· Click on the Input Settings panel to select the input files to use for modeling (Figure 11). Note that once all the input files have been selected appropriately, the error messages disappear.

Figure 11. Select Input Files

· On the Output Settings panel, select the location for output files (Figure 12).

Figure 12. Select Output Location

· The Runtime Settings panel is not used for this exercise.

· Click the Save button to save the modeling settings and load the input files (Figure 13).

Figure 13. Save Modeling Settings

· Once loading completes, click the Close button to return the main CAFE Model window. A new Compliance Model session, titled “Session 1” has now been created (Figure 14).

Figure 14. New Compliance Model Session Created

· Save the new session by selecting File > Save Session As.... Enter “demo.cmsd” in the dialog box that appears, and click the Save button (Figure 15).

Figure 15. Save New Session

· After the session has been saved, notice the title of the session has changed to “demo” (Figure 16).

Figure 16. “demo” Session Saved

· Select File > Start Modeling to start the compliance modeling process. As the model runs, the progress of the Compliance Model is displayed in the session window (Figure 17).

Figure 17. Modeling Progress from the Compliance Model

· After modeling has completed, the “Modeling Completed!” message appears at the bottom of the main CAFE Model window (Figure 18).

Figure 18. Compliance Model Completed

· Select View > Output Location to open Windows Explorer and browse to the location where model outputs for the “demo” session are saved.

· Exit the session by selecting File > Close Session.

· Exit the CAFE Model by selecting File > Exit, or proceed to the next example.

Example 2 – Configuring for Monte-Carlo Modeling

This example demonstrates how to take an existing session created in Example 1 – Configuring for Standard Compliance Modeling, and modify it to run the Monte-Carlo Model.

· Run the CAFE Model by clicking on the CAFE Model executable located on the desktop. Read through the Warnings dialog box, and then click the OK button.

· Select File > Open Session to open an existing modeling session. Select “demo.cmsd” in the dialog box that appears, and click the Open button (Figure 19).

Figure 19. Open “demo” Session

· Once the session has been loaded, select View > Modeling Settings to bring up the Modeling Settings window. There select the Monte-Carlo Model as in Figure 20.

Figure 20. Select Monte-Carlo Model

· Under the Input Settings panel, select a Monte-Carlo trials file (Figure 21).

Figure 21. Select Monte-Carlo Trials File

· The Output Settings and Runtime Settings panels are not used for this exercise.

· Click the Save button to save the updated modeling settings; then click Close, once saving completes.

· To prevent overwriting results from the “demo” session, select File > Save Session As... to save the modified session with a new name. For this example, the Monte-Carlo session was saved as “demo-mc.cmsd”.

· Select File > Start Modeling to start the Monte-Carlo modeling process. As the model runs, the progress of the Monte-Carlo Model is displayed in the session window (Figure 22).

Figure 22. Modeling Progress from the Monte-Carlo Model

· After Monte-Carlo modeling has completed, the “Modeling Completed!” message appears at the bottom of the main CAFE Model window. Select File > Exit to exit the model.

[1] The CAFE Model files provided may be in a zip archive, which will need to be extracted using a zip utility such as WinZip (www.winzip.com) or 7Zip (www.7-zip.org).

[2] It is recommended that users save the sessions prior to running them in order to assign a meaningful title to each session.