Surface Transportation Efficiency Analysis Model (STEAM 2.0)

This section will help you get started with STEAM 2.0, by providing you with a sequence of steps that allows you to do a simple analysis quickly. Let's suppose that you are interested in estimating the user impacts of a highway capacity improvement. You have your highway networks, travel demand matrices and centroid file prepared and ready for use. You're ready to use STEAM 2.0.

Scenario Description. Type the scenario description, and the location of the district file, if you wish to summarize user impacts by districts. The inset below shows you what a district file looks like. The file contains the number of the district and the name of the district, enclosed in quotes. You can use the "browse" button to identify the district file.

Scenario Description

Create the Scenario File. Use the File/Save As menu option to save the scenario file. The interface for saving all files in STEAM 2.0 should be familiar to you if you've used Microsoft Office products before. Type in the name of the new file, or select the name of an existing file, which will overwrite the information in that file. STEAM 2.0 automatically adds the ".bsn" file extension if you don't add any file extension. Using the ".bsn" file extension isn't necessary, but it makes finding scenario files much easier.

Create the Scenario File

Define Market Sector. Select the "Market Sector Information" option from the Tree Navigator and the associated screen appears to the right. Enter a name for the Market Sector (It can be a trip purpose, or a subset of the trip table), the base and improvement vehicle occupancy (all trip tables must be in person trips), the expansion factor (which converts daily impacts to annual impacts) and the value of time. Select the mode of travel and speed relationship (all STEAM 2.0'S speed equations estimate average daily speeds). Note that you can supply your own speeds in the network file, instead of using STEAM 2.0's speed equations. Finally, indicate whether you wish to perform either or both of the accessibility analyses.

Market Sector Information

Set Up Analysis. Select "Network and Trip Table Files" from the Tree Navigator.

Network Analysis. Select "Run Base/Run Improvement Network Analysis" if you are using STEAM 2.0 to develop O/D travel times. If you have a travel time file already created (this is a large binary file with a ".ttf" extension) and you wish to use it again, the check mark for the base or improvement case may be left blank. Check the "Ignore Travel Time Analysis" option if no travel time analysis is required. Remember that centroids are coded as facility type "7", and that any link coded with a zero capacity will be completely ignored in the analysis.

Base/Improvement Case Files. Select the input files you have prepared and a name for the binary output file (which STEAM 2.0 uses to summarize benefits and costs) using the "Browse" buttons. The formats for the network, matrix and zonal information file are described in Chapter 3.

Select Split Factor. If you are reporting results by district, and you wish to report user impacts to trip-makers who live in the district, then your matrices must be in P/A format. The split factor allows determines how many resident-trips leave the district and how many enter the district of residence. If you do not have a P/A matrix or wish to ascribe all district benefits to trips leaving the district, leave the P/A factor at the default figure of 100 percent.

Network and Trip Table File Names

If you have transit skims or parking costs you would like to use for your analysis, select "Other Changes Files" from the Tree Navigator. Base and Improvement, In-vehicle, out-of-vehicle and out-of-pocket costs may be specified. Each of these matrices expects values expressed in hundredths, e.g., $1.35 is expressed as "135" in these files.

Check Data Files

Check Data Files. From the main menu, select "Run/Check Input Files/Check Data Input Files". STEAM 2.0 will check all input files and develop a log file which notes any errors encountered. The check log may be viewed via the "View Data Check Log" menu option.

Check Data Files

Adjust Parameters and Develop Other Inputs. Use the main menu and the Tree Navigator to adjust various model parameters (such as fuel tax rates, shown below), define improvement costs, define changes in transit service, or to change the distribution of values for the Risk Analysis.

Model Parameters

Run Model

Run the Model. Assuming you've adjusted parameters to suit the requirements of your study, entered the proper capital cost data, etc., you are ready to run STEAM 2.0. Select "Run/Run model" from the main menu. Select "With" or "Without Risk Analysis". The STEAM 2.0 status window appears as shown here. You may cancel the process at any time.

Run the Model

Set Reporting Option

Set Reporting Option. STEAM 2.0's various reports are formatted for viewing by a text editor and a spreadsheet program. From the main menu, select "Tools/Reporting Options" and enter the directory path and name of the program you wish to use for the text editor and the spreadsheet program. If you don't know where these programs are located, try using the Microsoft Windows Explorer find option, under Explorer's "Tools" option, or ask your system administrator. You may change the number of columns that appear in each row of your reports as well. Generally, a font setting of eight works well with seven column-output in any text editor.

Reporting Options


Surface Transportation Efficiency Analysis Model (STEAM)	User Manual

	Select Market Sector. Select "Edit/Market Sectors" from the main menu. The Market Sector Screen pops up. Highlight "Mkt #1", then click on the "Modify" button. The Tree Navigator, as shown below, provides three options, "Market Sector Information, Network and Trip Table Files, and Other Changes Files."

5.0 Getting Started with STEAM 2.0