GradeDec.Net 

Users' Manual 

Federal Railroad Administration 

March 2017 

GradeDec.Net Users' Manual Contents  i 

Contents 

Introduction 1

Introduction to GradeDec.Net ................................................................................ 1

Why GradeDec.Net ................................................................................................ 2

Technical Description and Requirements 5

A Web-Based Application ...................................................................................... 5

Using GradeDec.Net - FAQs ................................................................................. 5

How do I access GradeDec.Net?................................................................ 5

How do I use GradeDec.Net? .................................................................... 5

Where do my data reside? .......................................................................... 6

Are my data secure? ................................................................................... 6

Terms of Use .............................................................................................. 6

Software and Hardware Requirements ................................................................... 8

Computer, Operating System and Web Browser ....................................... 8

Web Browser Settings ................................................................................ 8

File Formats ............................................................................................... 8

Overview of this Manual ........................................................................................ 9

Using GradeDec.Net 11

Introduction .......................................................................................................... 11

Modes of Use ........................................................................................................ 11

Safety Analysis ........................................................................................ 11

Full Investment Analysis ......................................................................... 11

The Data Hierarchy in GradeDec.Net .................................................................. 12

User .......................................................................................................... 14

Dataset ...................................................................................................... 14

Model Parameters and Other Data ........................................................... 15

Model ....................................................................................................... 15

Corridor .................................................................................................... 15

Region ...................................................................................................... 15

Scenario .................................................................................................... 15

Results ...................................................................................................... 16

Steps in Conducting a GradeDec.Net Analysis .................................................... 16

Overview .................................................................................................. 16

Safety Analysis ........................................................................................ 17

Full Investment Analysis ......................................................................... 20

GradeDec.Net Page-by-Page 23

Introduction .......................................................................................................... 23
ii  Contents GradeDec.Net Users' Manual 

1.1 Login Page ............................................................................................... 25

Overview .................................................................................................. 25

1.2 Registration Page ..................................................................................... 25

Overview .................................................................................................. 25

Login Assistance ...................................................................................... 26

2.1 Settings Page .................................................................................................. 26

Overview .................................................................................................. 26

Features .................................................................................................... 27

New Data Collection (Dataset, Corridor, Region, Scenario, Results) Page ......... 29

Overview .................................................................................................. 30

3.1 Crossings Page................................................................................................ 30

Overview .................................................................................................. 31

Features .................................................................................................... 32

Quick Import Page (invoked from the Crossings Page) ....................................... 37

Overview .................................................................................................. 37

Features .................................................................................................... 37

4.1 Import Page .................................................................................................... 39

Overview .................................................................................................. 39

Features .................................................................................................... 39

5.1 Scenario Page ................................................................................................. 41

Overview .................................................................................................. 41

Features .................................................................................................... 42

Scenario Input Variable Chart .............................................................................. 45

Overview .................................................................................................. 45

Features .................................................................................................... 45

6.1 Parameters Page.............................................................................................. 46

Overview .................................................................................................. 46

7.1 Simulation Page .............................................................................................. 47

Overview .................................................................................................. 47

Features .................................................................................................... 47

8.1 Results Page.................................................................................................... 50

Overview .................................................................................................. 50

Features .................................................................................................... 51

View results table and chart ................................................................................. 52

Overview .................................................................................................. 52

Features .................................................................................................... 53

Benefit-Cost Charts .............................................................................................. 55

Overview .................................................................................................. 55

Glossary of Terms 57

Index 63
GradeDec.Net Users' Manual Introduction  1 

Introduction 

Introduction to GradeDec.Net 

GradeDec.Net is a web-based decision support tool that assists federal, 

state and local authority decision makers in evaluating the benefits and 

costs of highway-rail grade crossing upgrades, separations and closures. 

GradeDec.Net employs benefit-cost methodologies that are used to 

evaluate highway-rail grade crossing investment alternatives at the 

corridor level or in a region. The modeling frameworks in GradeDec.Net 

were developed by the Federal Railroad Administration and include 

research findings of the Volpe National Transportation Systems Center 

and the National Cooperative Highway Research Program. GradeDec.Net 

analyses effectively support the planning and investment decision 

processes. 

GradeDec.Net forecasts the transportation and non-transportation effects 

of highway-rail grade crossing investments and estimates the economic 

value of these effects over the useful life of the project in dollar terms. 

The benefit-cost of an investment is calculated by comparing the timestream of expected economic benefits with the time-stream of investmentrelated and other costs, after adjusting for the opportunity costs of capital. 

Known as “discounting”, this adjustment enables decision makers to 

inspect future benefits and costs in terms of their present-day value. This 

is a standard way of giving due weight to nearer-term versus distant (thus 

less valued) outcomes. 

GradeDec.Net’s underlying methodology is consistent with the current 

benefit-cost methodologies employed by the United States Department of 

Transportation Agencies (Federal Railroad Administration, Federal 

Highway Administration, Federal Transit Administration, and the Federal 

Aviation Administration) and with Executive Order 12866, which 

governs the principles of federal infrastructure investment. The model is 

transparent in all of its assumptions and the model inputs are readily 

accessible to users who may want to adjust model inputs to reflect local 

circumstances. 
2  Introduction GradeDec.Net Users' Manual 

GradeDec.Net addresses two types of risk. First, accident risk is the 

probability of an accident occurring at a crossing. The principal metric of 

accident risk is the number of annual predicted accidents at a crossing (or 

in a corridor or region) by severity category (fatal, injury or property 

damage only). Accident risk is measured in GradeDec.Net using the 

U.S. Department of Transportation’s Accident Prediction and Severity 

(APS) model and a separate procedure that was developed for evaluating 

the accident risk associated with High Speed Rail (HSR) 

corridors. GradeDec.Net has recently added a module for evaluating the 

effects of aggravating risk factors on predicted accidents. 

GradeDec.Net also has capabilities for risk analysis, distinct from 

accident risk, which is concerned with quantifying uncertainty associated 

with forecasts. This second type of risk allows for the assigning of 

probability distributions to input variables of the analysis and determining 

the effects of uncertainty on the outcomes.

GradeDec.Net is designed to minimize the data needs and technical 

expertise required of the user while at the same time providing reliable 

benefit-cost results. With information about a series of grade crossing 

improvements along a particular corridor, the range of anticipated 

accident reductions, train crossing delay improvements, and travel 

demand forecasts generate preliminary benefit-cost results for a given 

confidence interval. Depending on the user’s needs, requirements, and 

abilities, one can select either an extensive default database that will 

minimize input requirements, or the user can customize the analysis by 

inputting project specific localized data. In this way, GradeDec.Net

functions as both a high-level preliminary model and a micro-level 

localized model. 

Why GradeDec.Net 

Growing requirements for highway-rail grade crossing investments and 

dwindling fiscal resources point to the need for a new tool for investment 

analysis. GradeDec.Net determines the effects rail corridor investments 

will have on safety and highway delay and queuing. Improvements will 

result in the following economic benefits: 

 Improvement in safety and reduced accident costs; 

 Reduced travel time costs; 

 Improved air quality; 

 Reduced vehicle operating costs; 

 Network benefits. 

GradeDec.Net uses risk analysis to evaluate highway-rail grade crossing 

investments and the results of an analysis include probability distributions 

for all of the model outcomes. These outcomes are viewed with 

GradeDec.Net’s user-friendly displays of charts and statistics. 
GradeDec.Net Users' Manual Introduction  3 

For a corridor or regional analysis, GradeDec.Net can evaluate up to 600 

grade crossings simultaneously. The user can view model results in total 

for the corridor or region, or by individual grade crossings. For example, 

the user can view the safety benefits of each grade crossing improvement 

along the corridor and the probability range associated with those 

benefits. Likewise, the user can view the highway vehicle operating costs 

savings or environmental benefits for each grade crossing. 

GradeDec.Net conducts comprehensive statistical simulations in order to 

provide a probability range for the net present value, and other results, 

associated with each rail corridor-level investment plan. This enables the 

user to assess the risk associated with each plan. Additionally, 

GradeDec.Net conducts risk sensitivity analyses based upon the 

probability ranges and informs the user which factors will have the 

greatest impact on the outcomes. For each result the user can display a 

"tornado chart" that shows the eight most significant factors contributing 

to risk. This information is essential for planning contingencies and 

working to mitigate risks. 

GradeDec.Net is deployed as a web-based decision support tool unlike its 

predecessor versions, which were desktop applications. Web deployment 

addresses the following issues: 

 Users are moving to secure systems and in some cases a 

requirement to install dedicated software is a barrier to use. 

GradeDec.Net does not require any special software, other 

than an Internet connection and a web browser. 

 GradeDec.Net does not require special hardware or even a 

special operating system (it will run on client computers 

running Windows, Linux, Unix or Mac operating systems). 

 Modifications and improvements to the software are 

immediately deployed for all users. 

 FRA’s most recent grade crossing data is always available to 

the application. 

 User analyses and data run on a central database thus 

minimizing the need for users to track and maintain their data 

on their computer (users have the option of storing their data 

locally at the end of a session and restoring their data for use 

when beginning a new session). 

GradeDec.Net Users' Manual Technical Description and Requirements  5 

Technical Description and 

Requirements

A Web-Based Application 

GradeDec.Net is a web-based application deployed over the Internet. 

This enables many users to access the system simultaneously, while using 

minimal resources from each user’s computer. 

The technical description of the system that follows is presented in the 

form of “FAQs” (frequently asked questions). This section concludes 

with the “Terms of Use” that apply to system users. 

Using GradeDec.Net - FAQs 

How do I access GradeDec.Net? 

Check the section below on “Software and Hardware Requirements” to 

verify that your computer is compliant. 

Open your web browser to the address (URL) http://gradedec.fra.dot.gov. 

When the logon screen appears, enter your user name and click “Submit”, 

and then enter your password and click “Submit” once more. New users 

should click on the ”Go” button on the right-hand side of the log-in 

screen for New User Registration. 

How do I use GradeDec.Net? 

After logging on, you can access all the features of GradeDec.Net. You 

navigate to the different functional areas of the system, each represented 

by a web page, by clicking on links of the main navigation menu (left side 

of the page). 

You develop your data and conduct your analysis by selecting options on 

the web pages of GradeDec.Net. When you make entries and click on 

selections in the web browser, a request is sent over the Internet to the 

GradeDec.Net server. The server performs all the calculations and data 

transformations and then sends back to your browser an updated page that 

reflects your selections. 
6  Technical Description and Requirements GradeDec.Net Users' Manual 

Where do my data reside? 

During a GradeDec.Net session, your data reside on the GradeDec.Net 

server. You may choose to leave your data on the server between 

sessions, or you can store it locally on your own computer and delete it 

from the GradeDec.Net server. When you start a new session, you can 

restore your data to the GradeDec.Net server and continue your analysis. 

Are my data secure? 

See “Data Security” in the GradeDec.Net Terms of Use below. 

Terms of Use 

The following are the GradeDec.Net Terms of Use: 

1. Purpose and Intended Use 

GradeDec.Net, system for highway-rail grade crossing investment 

analysis, is an online service provided by the Federal Railroad 

Administration (FRA). It is available to the general public and its 

intended users are: U.S. Department of Transportation employees; state 

and local authorities for transportation planning and policy; railroads; 

consultants, academics and others engaged in grade crossing policies and 

issues. The intended use of the system is for the development of analyses 

that support grade crossing management and investment decisions. 

2. General Disclaimer 

Use of the GradeDec.Net web application, documentation, or data is 

without warranty of any kind by FRA. To the maximum extent permitted 

by applicable law, FRA further disclaims all warranties, including 

without limitation any implied warranties of merchantability, fitness for a 

particular purpose, and noninfringement. The entire risk arising out of 

the use or performance of the GradeDec.Net web application, 

documentation, or data remains with the user. To the maximum extent 

permitted by applicable law, in no event shall the FRA or its contractors 

be liable for any consequential, incidental, direct, indirect, special, 

punitive, or other damages whatsoever (including, without limitation, 

damages for loss of business profits, business interruption, loss of 

business information, or other pecuniary loss) arising out of the use of or 

inability to use the GradeDec.Net web application, documentation, or 

data, even if FRA has been advised of the possibility of such damages. 

3. Applicability of Models, Supplied Values and Assumptions 

GradeDec.Net includes modeling frameworks, sample analyses and 

default values for a range of model parameters and input variables. FRA 

does not guarantee that these are well-suited for a particular analysis or 

situation. It is the user's responsibility to validate all inputs and 

assumptions for the analyses generated by GradeDec.Net. 
GradeDec.Net Users' Manual Technical Description and Requirements  7 

4. Non-Endorsement of Results 

Results that are obtained from GradeDec.Net analyses are solely the 

responsibility of the user and are not endorsed by FRA. 

5. Availability of Service and Outages 

FRA seeks to provide GradeDec.Net as an "always on" service. 

However, there may be service outages due to any of the following 

factors: disruptions in the power supply, disruptions in the data 

communications network, equipment failure or system maintenance. 

FRA is not liable for damages that might result from service outages. 

6. Possible Discontinuance of Service 

FRA reserves the right to discontinue this service, temporarily or 

permanently, and without advance notice. FRA is not liable for damages 

that might result from the discontinuance of service. 

7. Data Security 

a. Transmission 

GradeDec.Net uses secure socket layer (SSL) technology in accordance 

with the latest standards and protocols. Your data are secure in 

transmission between your local computer and the GradeDec.Net server. 

b. Storage on the GradeDec.Net server 

User analysis data resides on the GradeDec.Net server computer during 

an analysis session, and the user has the option of allowing data to remain 

on the server between analysis sessions. FRA will take reasonable 

measures to ensure the integrity and privacy of the user's data. However, 

FRA does not guarantee that the integrity or privacy of data will not be 

compromised due to either technical failure or the actions of an 

unauthorized third party. FRA is not liable for any damages that might 

result from the loss of data or their access by unauthorized parties. The 

user has the option of storing analysis data offline on the user's computer 

between sessions, deleting it from the GradeDec.Net server computer, 

and restoring it to the server for use in subsequent sessions. 

8. Denial of Access for Misuse 

FRA reserves the right to deny access to a party that seems to be misusing 

the system. Misuse of the system includes, but is not restricted to: 

hacking, deliberately circumventing system security, overloading, 

attempting to deny service to others, attempting to use system resources 

for purposes other than the system's intended use. 
8  Technical Description and Requirements GradeDec.Net Users' Manual 

Software and Hardware Requirements 

Computer, Operating System and Web Browser 

GradeDec.Net is designed for use with any computer and operating 

system running most popular browsers current since 2005. 

The required hardware is the same as that required to run the web browser 

on a specific platform (type of computer and operating system). 

And, of course, all browsers require a mouse (or other pointing device) 

and an Internet connection. 

Web Browser Settings 

This section discusses several browser settings that you may need to 

adjust in order to use GradeDec.Net. These settings can be accessed from 

your browser’s main menu. In Internet Explorer use the menu option 

Tools>Internet Options. 

Cookies 

GradeDec.Net uses session cookies. Your browser should allow session 

cookies with most privacy settings except “Block all cookies”. Session 

cookies promote the security of your session without compromising your 

privacy. 

Security and Other Settings 

The following security settings must be enabled in your browser in order 

to use GradeDec.Net and all of its features. 

In Internet Explorer, under “Security” you must enable: 

 “Active scripting” 

 “Downloading of files” 

With Netscape, you must check under Advanced>Scripts & Plug-Ins: 

 “Enable JavaScript with Navigator” 

Also with Netscape, under Navigator>Downloads> you must select one 

of the following options: 

 “Open the download manager” 

 “Open a progress dialog” 

File Formats 

Some of the optional features of GradeDec.Net involve the transfer of 

files between the GradeDec.Net server and your computer. The 

following are the file formats used in these transfers: 
GradeDec.Net Users' Manual Technical Description and Requirements  9 

 ZIP files are used when downloading data for storage between 

sessions. The user has no need to access these files locally. 

 PDF, or portable document files are used with GradeDec.Net 

reports. In order to view and print these files, you should 

have Adobe Acrobat Reader or other compatible software 

installed on your computer in order to read and print these 

files. 

Overview of this Manual 

The remainder of this document describes how to conduct a 

GradeDec.Net analysis and use the pages that are encountered during an 

analysis. The manual concludes with a glossary of terms and an index. 

Note that the GradeDec.Net Model Reference Manual is the companion 

piece to this User’s Manual and may be required to fully understand some 

of the features and processes of GradeDec.Net that this manual describes. 

In the text, the following conventions are used: 

 Bold text is used to refer to a page in GradeDec.Net (e.g., 

Settings page). The same bold text will be used when 

referencing the links to these pages from the main navigation 

menu. 

 Italics are used to designate drop down list options and 

selections in GradeDec.Net (e.g., Add new crossing) 

GradeDec.Net Users' Manual Using GradeDec.Net  11

Using GradeDec.Net 

Introduction 

This chapter gives general guidance on working with GradeDec.Net. The 

first section describes the principal modes of use for GradeDec.Net. The 

section that follows describes the management of data in GradeDec.Net. 

The final section describes the steps taken to conduct an analysis for each 

of the modes of use. 

The subsequent chapter,”GradeDec.Net Page-by-Page”, provides detailed 

descriptions of all the features of GradeDec.Net. 

Modes of Use 

GradeDec.Net has several modes of use, and the specific mode of use that 

you choose will depend upon the type of decision that your analysis 

should support. This section identifies and describes the two principal 

modes of use with GradeDec.Net. These are: 

 Safety analysis, and 

 Full investment analysis 

Safety Analysis 

For a safety analysis, the user examines predicted accidents at grade 

crossings and for the corridor (or region) as a whole. The safety analysis 

is, essentially, a comparison of a “before” and “after” situation, where 

“before” represents the status quo and “after” reflects the impact of 

crossing improvements (through device upgrade, closures, separations, 

traffic management measures, etc.) The safety analysis is restricted to 

examining the safety impacts at a crossing. The safety analysis reflects a 

snapshot of current conditions and does not account for the forecast 

growth of highway traffic or rail operations. 

Full Investment Analysis 

A full investment analysis supports resource allocation and planning 

decisions. The full investment analysis accounts for safety benefits and, 

as well, other highway user costs. These user costs include time savings, 

vehicle operating costs and emissions. The full investment analysis 

monetizes the benefits from each benefits category and sums the benefits 
12  Using GradeDec.Net GradeDec.Net Users' Manual 

from the improvements over the time horizon of the investment. This 

analysis includes user assumptions regarding the forecast of traffic 

growth, by highway and rail, and analyzes the risk associated with the 

forecast values. 

A “safety analysis” will involve a subset of the GradeDec.Net features 

required for a “full investment analysis”. The following table shows the 

two modes of use, purposes associated with each, and the functional 

pages in GradeDec.Net used in each type of analysis. 

Table 1 GradeDec.Net Modes of Use 

Mode of Use Purpose Functional 

Pages in 

GradeDec.Net 

to Use

Safety analysis Calculate accident risk and 

impacts of improvements, 

identify improvement 

programs, analyze safety

regulatory impacts

Support safety and 

regulatory compliance 

decisions.

Settings, Import, 

Crossings, Parameters

Full investment 

analysis

Benefit-cost and risk analysis

of programs of 

improvements; analyze 

safety, delay and user cost 

impacts

Support resource allocation 

and investment decisions. 

Support planning process. 

Settings, Import, 

Crossings, Parameters, 

Scenario, Simulation, 

Results

The Data Hierarchy in GradeDec.Net 

In order to conduct analyses effectively in GradeDec.Net you should be 

familiar with its data hierarchy. 

Every active session of GradeDec.Net has a data hierarchy that is 

populated with values at all times. These values correspond to the current 

selections of data collections that are viewable, editable and are used in 

GradeDec.Net model calculations. You navigate among different data 

collections by making selections on the Settings page, which sets the 

values in the data hierarchy. 

The data hierarchy is shown in the figure below. A brief description of 

each of the nodes (boxes) in the figure follows at the end of this section. 
GradeDec.Net Users' Manual Using GradeDec.Net  13

Figure 1 Data Hierarchy in GradeDec.Net 

The connecting lines in the data hierarchy figure mean that the lower 

node is a “child” of the parent node above it to which it is connected. 

When you change the value of a parent node (by making a selection in the 

Settings page) you are also re-populating the nodes in the hierarchy 

below the parent with values that represent data collections belonging to 

the newly selected parent node value. 

For example, when a newly registered user logs on, the data hierarchy is 

populated with values like in the table below. 

Table 2 Data Heirarchy at New User Logon 

Data Hierarchy 

Node

Value

User Your user id

Dataset “Initial dataset”

Model “Corridor Model”

Corridor “South Empire”

Scenario “Strong rail growth”

Result “Placeholder – Corridor Model”

Suppose the user then changes the Model selection in the Settings page to 

“Regional Model”. The data hierarchy will then be populated with the 

following values (changed values in italics): 

Collection of

Scenario data

Collection of

Crossing data

Collection of

model

parameters

and other

data

User

Dataset

Model

Corridor

or Region Scenario Results
14  Using GradeDec.Net GradeDec.Net Users' Manual 

Table 3 Data Heirarchy After Changing Model 

Data Hierarchy 

Node

Value

User Your user id

Dataset “Initial dataset”

Model “Regional Model”

Region “Montgomery, MD”

Scenario “Strong highway growth”

Result “Placeholder – Regional Model”

For every parent node value there are designated default values for its 

child nodes, which fill the data hierarchy when the parent node value is 

selected. When you first register as a GradeDec.Net user you are 

assigned an “Initial Dataset” that includes data collections with sample 

values, and the system designates some of these data collections as 

defaults. You can never delete a data collection that is a default of its 

parent node. You can designate another data collection to be a default, 

and then delete the collection that was previously designated as default. 

You can create and delete data collections, set their defining values and 

set defaults from the Settings page. 

The following are descriptions of the nodes in the data hierarchy. 

User 

When you log in to GradeDec.Net, a value representing your user account 

is set in the User node. This never changes during your session and 

ensures that users can only access their own data and not those of others. 

Dataset 

User data for analyses are organized in datasets in the GradeDec.Net

database. A user may create and maintain up to 10 datasets. A dataset is 

a comprehensive container of data collections used in GradeDec.Net

analyses. Note that data from different datasets cannot be combined in a 

single analysis. You can use datasets to preserve a baseline analysis, and 

then develop new analyses from copies of the baseline. You can 

download a dataset to your computer and restore it to the system at a later 

date. You can also share data with a colleague by sending him or her 

your downloaded dataset, which your colleague can then upload during a 

session with GradeDec.Net. 

Access the options for selecting, creating, deleting, downloading and 

uploading datasets from the Settings page. 
GradeDec.Net Users' Manual Using GradeDec.Net  15

Model Parameters and Other Data 

Each dataset contains a set of model parameters including: crossing 

device effectiveness rates; model coefficients for emissions and fuel 

consumptions calculations; high speed rail model calculations – see the 

Model Reference for a full description. “Other data” refers to traffic 

time-of-day distributions and cost data for grade crossings device and 

supplementary safety measures. 

These parameters and data are specific to the selected dataset and can be 

viewed and modified from the Parameters page. 

Model 

GradeDec.Net has both a corridor model and a regional model. The data 

requirements are slightly different for each model so that data collections 

below the Model node are specific to the selected model. 

Corridor 

A corridor has a set of defining values (these can be viewed and modified 

in the data grid at the bottom of the Settings page – see Section 2.1 

Settings Page below) and refers to a collection of grade crossings along a 

single rail alignment. A corridor is selected in the data hierarchy only if 

the Model node is set to the corridor model. A dataset will contain at 

least one corridor and may contain as many as 50. 

Create and delete corridors and modify their defining values in the 

Settings page. After selecting a corridor, view or modify its crossings 

data from the Crossings page. 

Region 

A region has a set of defining values (these can be viewed and modified 

in the data grid at the bottom of the Settings page – see Section 2.1 

Settings Page below) and refers to a collection of grade crossings in a 

designated region. A region is selected in the data hierarchy only if the 

Model node is set to the regional model. A dataset will contain at least 

one region and may contain as many as 50. 

Create and delete regions and modify their defining values in the Settings 

page. After selecting a region, view or modify its crossings data from the 

Crossings page. 

Scenario 

A scenario has a set of defining values (a description, start year, last year 

of near term, and end year) and an associated collection of scenario data. 

A dataset will contain at least one scenario for each of the two models and 

a dataset may contain as many as 30 scenarios for each model. 
16  Using GradeDec.Net GradeDec.Net Users' Manual 

Create and delete scenarios and modify their defining values from the 

Settings page. After selecting a scenario, view and modify the scenario 

data from the Scenario page. 

Results 

GradeDec.Net sets the defining values of a results set automatically when 

you run a simulation. You can set the description for a results set. 

Create and delete result sets and modify its description from the Settings

page. After selecting a results set and running a simulation, view results 

from the Results page. 

Steps in Conducting a GradeDec.Net Analysis 

Overview 

The following table shows a sample set of steps that you would undertake 

to conduct each of the two analyses. The sections that follow walk you 

through these steps in a sample analysis. Additional detail is provided in 

the “GradeDec.Net Page-by-Page” chapter, including screen snapshots. 
GradeDec.Net Users' Manual Using GradeDec.Net  17

Table 4 GradeDec.Net Modes and Sample 

Mode of Use Functional Steps Page

Safety analysis (Optional) Create and select a new 

dataset

Settings

Create and select a new corridor (or 

region)

Settings

Set values for corridor (or region) Settings

(Optional) Set default crossing 

device cost data

Defaults

Import data from Grade Crossing 

Inventory

Import

Verify and refine data, assumptions 

and choice of alternative

Crossings

Calculate predicted accidents, 

view/print reports and charts

Crossings

Full investment 

analysis

Conduct all of the steps in the 

“Safety analysis” mode of use listed 

above

Create new results set Settings

Create new scenario Settings

Populate the scenario data with 

forecast data and assumptions

Scenario

Verify and modify parameters and 

other data values

Parameters

Set the simulation parameters and 

run the simulation

Simulation

View results table and charts, print 

report

Results

Safety Analysis 

In this example you will set up an analysis for 10 crossings in a freight 

rail corridor in Lincoln County, Nebraska. 

(Optional) Create and select a new dataset

If you skip this step, then in subsequent steps you will be using the 

default or other existing dataset. 

On the Settings page, click on the link “Create New Dataset” on the row 

with “Selected Dataset”. This will transfer you to the New Dataset page. 

On this page you choose to either “Create new dataset by copying a 

dataset” – in which case you select one of your datasets from the drop 

down list – or choose “Create new dataset from sample data”. Select the 

second option. 
18  Using GradeDec.Net GradeDec.Net Users' Manual 

Enter a name for the new dataset (e.g., “Sample analyses”) and then click 

create. This will transfer you back to the Settings page. From the dataset 

drop down list, select the dataset that you just created and click “Go”. 

Create and select a new corridor (or region) 

This section will assume that the Corridor Model is suitable for your 

analysis. 

Select the “Corridor Model” (or ensure that it is selected) by clicking the 

appropriate button on the “Select Model” line. 

On the Settings page, click on the link “Create New Corridor” to the right 

of “Selected Corridor”. This will transfer you to the New Corridor page. 

On this page select “Create a new, empty corridor”. Enter a name for the 

new corridor (e.g., Lincoln 1) and then click create. This will transfer 

you back to the Settings page. 

Enable the “Corridor” drop down list by selecting the radio button by 

“Selected Corridor” (or ensure that it is selected). 

From the “Selected Corridor” drop down list, select the corridor that you 

just created. 

Set values for corridor (or region) characteristics 

In the table at the bottom of the Settings page you need to set the 

characteristics that correspond to your corridor. This includes: the 

number of daily trains by type, the time-of-day distribution for rail 

operations in the corridor, specify yes/no whether highway traffic signals 

in the corridor are synchronized with crossing signals. 

In this example, set: 

 Daily Passenger Trains to 0 

 Daily Freight Trains to 108 

 Daily Switch Trains to 1 

 Rail TOD (time-of-day) distribution to Uniform 

 Signal Synchronization to false by leaving it unchecked 

Set the values in the table by clicking on the “Edit” button, which will 

open the table for editing. Enter your changes and save them by 

clicking the “Update” button.” 

(Optional) Modify or Add Time-of-Day Traffic Distributions. 

If the sample time-of-day traffic distributions provided adequately reflect 

the distributions of highway traffic at crossings and for rail movements in 

the corridor, then skip this step. Otherwise, browse to the Parameters 

page by clicking on the link on the main navigation menu. On this page 

select from the toolbar at the top “Other data”. 

Add new time-of-day crossings distributions as needed. 
GradeDec.Net Users' Manual Using GradeDec.Net  19

(Optional) Set default crossing device cost data 

If in your analysis of safety you have no interest in the costs of 

improvements, then skip this step. 

Browse to the Parameters page by clicking on the link on the main 

navigation menu. On this page select from the toolbar at the top “Other 

data”. From the drop down list select crossing device costs. Enter 

alternative values to the ones listed, as needed. 

Import data from Grade Crossing Inventory 

From the main navigation menu, select the Import page. From the drop 

down lists on the left select: 

 State: Nebraska

 County: Lincoln

 Area: Whole County

The “Selected Areas” table will show your selection. Click on the button 

“Create list of corridors in selected areas”. The list of corridors will 

appear as options in the following drop down list. Select the corridor: UP 

Nebr Eastern 4 Crossings. This is the corridor with crossings in the 

selected area for the UP railroad, Nebraska division, Eastern subdivision. 

In this example there are four crossings. 

You can view the National Grade Crossings Inventory data for the 

selected crossings at the table at the bottom of the page. You can modify 

the options and criteria that appear on the right side of the page (see the 

section 5.1 Import Page section for full description), or you can just click 

on “Import crossings data” to import your data to your Lincoln 1 corridor. 

After clicking import, your browser will automatically shift to the 

Crossings page. 

Verify and refine data, assumptions and choice of 

alternatives 

In the Crossings page you can browse the imported data and make any 

modifications that you need. Also, in the “General” section you can view 

and modify the choices for the improvement alternative. 

Calculate predicted accidents, view/print reports and charts 

When you are satisfied with the data and the alternative selections, on the 

“APS model” section click on the “Calculate predicted accidents” link in 

order to calculate the predicted accidents for each crossing and for the 

whole corridor. 

You can generate a report for viewing and printing by selecting the option 

under “Crossings” on the Main Menu. You can view a chart of the 

predicted accidents by selecting the “View chart” link in the “APS 

Model” section of the Crossings page. 
20  Using GradeDec.Net GradeDec.Net Users' Manual 

Full Investment Analysis 

For a full investment analysis, complete the steps above for the safety 

analysis. Then perform the following steps. 

Create new results set 

On the main navigation menu, click on the link Settings to return to the 

Settings page. On the Settings page, click on the radio button “Results” 

on the “View in table below the selected” . Then , on the “Selected 

results set” line, click the ”Create New Results Set” links. This will 

launch the New Results page. On this page, enter the name of the new 

results set “Lincoln UP, Base” and then click the “Create” button. Your 

browser will create the results set and shift back to the Settings page. 

Now from the drop down list select the newly created results set. 

Create new scenario 

Now click on the radio button ”Scenario” on the “View in table below 

selected” line. Then click the “Create New Scenario” button on the 

“Selected Scenario” line. This will launch the New Scenario page. 

Select “Create a new scenario by copying an existing scenario” and select 

from the drop down list the sample “Base scenario” scenario. Enter a 

name for the scenario (e.g., Lincoln base) and click on “Create”. Your 

browser will create the scenario and shift back to the Settings page. Now 

from the drop down list select the newly created scenario. 

You can leave the year settings (Start year: 2018, last year near term: 

2022, end year: 2042) at their default values or modify them if you wish. 

These vales determine the first and last years of the analysis time horizon 

and the periods in which the respective near-term and far-term growth 

rates are applied. 

Modify the scenario data with forecast values and 

assumptions for your analysis 

Click on the Scenario link of the main navigation menu. Your browser 

will transfer to the Scenario page. This page will display the scenario 

that you selected. This scenario is pre-populated with the sample values 

copied from the “Base scenario”. Modify these values to suit your 

analysis. 

The scenario data variables are organized by topic areas: rail operations, 

highway, social costs and prices. You select a topic area by using the 

drop down list on the top-center of the page. You view a variable within 

a topic area in the table in the lower part of the page. Clicking the “Edit 

Distributions” and “Edit Values” buttons allows you to edit the variable 

data in the table. 

The data for the scenario variables are either a fixed value or several 

values that define a probability distribution. Click on the “Edit 

Distributions” button to select the type of probability distribution using 

the drop down lists (skewed bell, normal, uniform or triangle – or set the 
GradeDec.Net Users' Manual Using GradeDec.Net  21

variable to be a “Fixed Value”). After setting the probability distribution 

types for all the variables on the page, click “Update”. Then click the 

button “Edit Values”, which will open the table to allow editing of the 

values. After entering the values for the probability distributions on 

the page, click the “Update” button to save your entries. Be sure to 

always click “Update” to save your entries before navigating away from 

your current page. 

Verify or modify parameters and other data values 

Browse to the Parameters page by clicking on the link on the main 

navigation menu. On this page select from the toolbar at the top “Model 

Parameters”. Select from the drop down list a table of values to view. If 

for your analysis you have local information that is better suited than the 

standard values supplied with GradeDec.Net, then edit the model values 

here (see the Model Reference for documentation of the equations in 

GradeDec.Net).

Set the simulation parameters and run the simulation 

Browse to the Simulation page by clicking on the link on the main 

navigation menu. On this page set the parameters for running a risk 

analysis of the benefit-cost of the program of improvements defined in 

Crossings, with the probability distributions described in Scenario. You 

can run your simulation with the default values, or modify them and take 

advantage of the options on this page. When ready, click on the ”Run 

Simulation” button. When completed, your browser will shift to the 

Results page.

View results table and charts, print report 

On the Results view your analysis results on the tables and charts that 

this page makes available. 

GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  23

GradeDec.Net Page-by-Page 

Introduction 

The figure below shows the pages in GradeDec.Net and the means for 

accessing each page (pages directly connected to the main navigation 

menu are accessed from it. Access other pages from the connecting page 

to its left in the figure). The following descriptions of pages each contain 

an Overview and a Features section. 
24  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

Figure 2 Key to Pages in GradeDec.Net 

1 0 .1 U s e r's H e lp

M a in N a v ig a tio n M e n u

2 .1 S e ttin g s

3 .1 C ro s s in g s

4 .1 Im p o rt

5 .1 S c e n a rio

6 .1 P a ra m e te rs

7 .1 S im u la tio n

8 .1 R e s u lts

1 1 .1 R e fe re n c e h e lp

1 .1 L o g in 1 .2 N e w u s e r re g is tra tio n

URL : h ttp ://g ra d e d e c .fra .dot.gov

9 .1 R e p o rts
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  25

1.1 Login Page 

Figure 3 View of Login Page (Login and registration section) 

Overview 

After directing your browser to the GradeDec.Net URL 

(http://gradedec.fra.dot.gov ), the Login page appears. The Login page 

contains a toolbar with selections that offer information about 

GradeDec.Net. When “Login” is selected, you will see the “Login and 

Registration” section as it appears above. 

Enter your user ID and click “Submit”. Then enter your user password 

and click “Submit” to begin a GradeDec.Net session. 

First-time users should click the “Go” button on the right in order to 

invoke to the Registration page for new user registration. 

1.2 Registration Page 

Figure 4 View of Registration Page 

Overview 

On this page, first-time users register with GradeDec.Net. Required 

information includes the user ID, password, first name, last name and an 

email address. The user ID and password must each be at least six 

characters in length. Please note and save your user ID and password in a 

safe place because you will need these for logging in to GradeDec.Net in 

future sessions. 
26  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

After entering your information, click “Submit”. Missing or invalid 

information will result in red error messages on the page. If you see any 

such messages, correct as needed and click “Submit” again. After you 

register, your browser will be redirected to the Settings Page. 

Login Assistance 

Figure 5 View of Login Assistance Page 

If you forget your password, you can go to the Login Assistance Page.

On this form, you enter your GradeDec.Net user name, click submit, and 

you will receive an email (sent to the email address associated with the 

registered user) with instructions on how to change the password. 

Should you forget your GradeDec.Net user name, send an email to 

Karen.mcclure@dot.gov. You will receive an email with instructions for 

resetting and accessing your account. 

2.1 Settings Page 

Figure 6 View of Settings Page 

Overview 

With the Settings page, use the controls on the page to set and manage 

the data collections for your analysis (see the section on “The Data 

Hierarchy in GradeDec.Net”). You can also modify the defining values 

for data collections, set or restore defaults and launch the page to create 

new data collections or delete existing ones. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  27

Features 

The Settings page is divided into two main sections: 1) the object 

selection form (top of the page) and 2) the data grid (bottom of the 

page). Use the controls in the object selection form to select an object 

(corridor or region, scenario or results set) and edit the object’s 

characteristics in the data grid. Click the “Edit” button in order to make 

entries in the data grid and click “Update” to save your entries. The 

following subsections describe in detail the features of the page. 

 Select Dataset drop down list – if you have more than one 

dataset, select the one to use with this control.

 Go/Enable toggle buttons – By clicking one of these buttons 

when it says “Enable” you enable the drop down list to its left for 

use. By clicking one of these buttons when it says go, you select 

the item in the drop down list on the left. Item selection will 

cause the grid at the bottom of the page to be populated with data 

defining the selection.

 Select Model toolbar – within the selected dataset, select the 

model (Corridor or Regional) to use by clicking the respective 

button on the toolbar. The Corridor model examines crossings 

along a designated rail alignment and calculates impacts in the 

corridor, while the Regional model looks at all crossings in a 

specified region.
28  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

 Select Corridor/Region, Scenario, Results Set toolbar – this 

toolbar has three buttons, and one of these will always be 

selected. The toolbar selection determines: a) the options 

available in the Object drop down list, b) the “Create” and 

“Delete” object links. When selecting one of the options:

o Corridor or Region (“Corridor” will be the first option if 

“Corridor Model” is selected in the Select Model toolbar. 

If “Regional Model” is selected then the first option will 

be “Region”). – Selecting corridor or region will populate 

the Object drop down list with the Corridors or Regions 

in the dataset. The “Create” link will display “Create new 

corridor/region” and the “Delete” link will display “Delete 

corridor/region”.

o Scenario – Selecting “Scenario” will populate the Object

drop down list with the scenarios in the dataset. The 

“Create” link will display “Create new scenario” and the 

“Delete” link will display “Delete scenario”.

o Results Set – Selecting “Results set” will populate the 

Object drop down list with the results sets in the dataset. 

The “Create” link will display “Create new results set” 

and the “Delete” link will display “Delete results set”.

 Object drop down list – Select the corridor or region, scenario or 

results set for your analysis. Use the Go/Enable toggle button to 

the right of the drop down list in order to execute your selection. 

 Data Collection data grid (located at the bottom of the Settings

page) – After selecting a data collection with the drop down lists 

above, its defining values will appear in the data grid at the 

bottom of the page. You can edit some of the values in the table 

by clicking the “Edit” button. Some values are modified by the 

program and cannot be manually edited. After clicking the “Edit” 

button, editable values will show a control (a text box, drop down 

list, or check box) that can be modified. After making edits, click 

the “Update” button saves the edits, or click the “Cancel” button 

to delete the edits you made. 

 Create New Dataset link - Invoke the page for creating a new 

dataset.

 Delete Dataset link – Delete the selected dataset (note that you 

cannot delete a default dataset – if it is default, then select a 

different dataset and set it as default (using “Save current 

selections as defaults” from the Navigation Menu Submenu) and 

then delete the originally selected dataset. 

 Create New Corridor, Region, Scenario or Results Set link - 

Invoke the page for creating a new data collection 

(corridor/region, scenario or results set, depending upon which 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  29

you have selected from the Select Corridor/Region, Scenario, 

Results Set toolbar).

 Delete Corridor, Region, Scenario or Results link – Delete the 

selected data collection (note that you cannot delete a default data 

collection – if it is default, then select a different data collection 

and set it as default and then delete the originally selected data 

collection). 

 Navigation Menu Submenu – from this menu (on the left side 

of the page) under the ‘Settings’ option, access the following: 

o Reload defaults – Some of your data collections are 

designated as “defaults”, which are set as “selected” when 

you begin your GradeDec.Net session. This action 

restores set your default settings as the current settings. 

o Save current selections as defaults – This action will 

replace your default settings with the ones that are current. 

o Archive dataset to local disk – When you archive a 

dataset, you download a ZIP file to your computer that 

contains a replica of all the data in your dataset. The 

archived dataset is for storage and sharing with another 

user. It is not in a suitable format for offline modification 

of data. After downloading your dataset you can delete 

the dataset (if you so choose – see “Delete Dataset Link” 

above) from the GradeDec.Net server database and 

restore the archived dataset to the server at a later date. 

o Restore archived dataset – Select this action to upload and 

restore an archived dataset to the GradeDec.Net server. 

New Data Collection (Dataset, Corridor, Region, 

Scenario, Results) Page 

Figure 7 View of New Data Collection Page 
30  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

Overview 

Invoke this page from the Settings page and use it to create a new data 

collection. Each page will request that you specify “Create new data set 

from sample data” or “Create new data set by copying a data set.” For a 

new data set, select the first radio button, to copy an existing data set, 

choose the second button. In both cases, you need to assign a new name 

to the data collection. 

For a new corridor or region, selecting a “new empty” corridor or region, 

creates a placeholder region or corridor that contains no grade crossings. 

You must add grade crossings afterwards either manually (from the 

Crossings page or by importing data (through “Quick Import” on the 

Crossings page or from the Import page. 

3.1 Crossings Page 

Figure 8 View of Crossings Page with the Corridor Model 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  31

Figure 9 View of Crossings Page, with Corridor Model and Capital 

Programming, Devices Displayed 

Overview 

Use this page in safety or investment analysis to: 

 View crossing data. 

 Add, modify and delete crossing data. 

 Calculate predicted accidents using both the Accident Prediction 

and Severity Model and the High Speed Rail Model 

 Print the crossings reports 

 View charts ranking the crossings 

The Crossings page shows data and permits editing data for the crossing 

selected in the list at the top of the page. The toolbar in the middle of the 

page permits selection of the section of data to view for the crossing. For 

the Corridor Model the toolbar shows the following sections: 

 General 

 Devices 

 Highway 

 Rail 

 Cost 

 APS (Accident Prediction and Severity) Model 

 HSR (High Speed Rail) Model 

For the Regional Model the toolbar shows the following sections: 

 General 

 Devices 
32  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

 Highway 

 Rail

 Cost 

 APS (Accident Prediction and Severity) Model 

Additionally, if the crossing variable (in the Highway section) called 

“Traffic Management Measure?” is set to “True” then the toolbar will 

include the following section: 

 Highway (Alt.) 

Similarly, if the crossing variable (in the APS model section) called 

“Include Aggravating Factors?” is set to “True” then the toolbar will 

include the following section: 

 Aggravating Factors 

The items listed in some of the sections will vary, depending upon 

whether the user has set “Allow Capital Planning” to “True” for the 

corridor or region (on the Settings page). Without capital planning, the 

user is selecting a Base Case and an Alternate Case, with all upgrades 

implemented in the base year for the alternate case. With capital 

planning, the user can set the year for implementing the improvement for 

each crossing. The user can also specify with capital planning two phases 

of upgrades (i.e., upgrade to gates in year 3 then grade separate the 

crossing in year 15). 

Features 

The Crossings page is divided into two main sections: 1) the crossings 

selection form (top of the screen), and, 2) the data grid (bottom of the 

screen). Data entry and modifications to crossing data are entered on the 

data grid subsequent to clicking the Edit button. You navigate among 

topics for the crossings by clicking on the buttons in the middle of the 

page. Note that the Crossings page appears different depending upon 

whether the “Allow Capital Programming?” setting is set to true. See 

Figures 8 and 9 above. (You set the setting “Allow Capital 

Programming?” in the Settings Page by editing the data for the selected 

corridor).

If set to true, then in the General Information section, there will be data 

entry drop down lists for two alternatives (Phase I and Phase II) and their 

respective years for implementation. Also, on the toolbar at the top of the 

page the user can specify the year for comparing base and alternate 

accident risk, which will account for the improvements in the alternate 

case for the year specified. 

Several buttons on the form facilitate updates, calculations and navigation 

among crossings and are discussed below. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  33

 Other features can be accessed from the Crossings link in the navigation 

menu. 

The Crossing List Box 

This box displays a list of all the crossings in the corridor or region. You 

can select a crossing to view and edit by first clicking on the crossing 

(which highlights the crossing in the box) and then clicking on the “Go” 

button. You can also select a crossing by using the up and down arrows. 

Up and Down Arrows 

Clicking on these arrows moves the selection to the next or previous 

crossing in the crossing list box. When the selected item changes, the 

data grid displays the data of the selected crossing. 

Delete Crossings Mode 

When the page is in “Delete Crossings Mode” you can delete one or 

multiple crossings. To put the Crossings page into “Delete Crossings 

Mode”, click the Enter “Delete Crossings Mode” link in the upper righthand corner of the page. Select a crossing by clicking on it from the 

menu and use either the shift or ctrl keys to select multiple ones. When 

your selection has been made, click the Delete the selected crossings link 

where the Enter “Delete Crossings” Mode link once was. Click the Exit 

“Delete Crossings” mode to return to the Crossings page. 

Navigation Menu Submenu 

Access the Navigation Menu Submenu on the Navigation Menu (on the 

left side of the page under the “Crossings” option). The following 

describe the components of the menu. 

 Add new crossing - This action will create a new crossing in the 

corridor or region and will populate it with sample values. Using 

the “Edit” feature, you should modify the sample values with your 

crossing data. 

 Quick Import - This page is invoked from the Navigation Menu 

Submenu under the Crossings option when the Crossings page is 

displayed. Use Quick Import to import a small number of 

crossings to the corridor or region, whose FRA grade crossing ID 

numbers you already know. 

 Set default costs (this crossing) - This action will apply the default 

costs (see the Parameters page) to the selected crossing in the 

corridor or region. 

 Set default costs (all crossings) - This action will apply the default 

costs (see the Parameters page) to all of the crossings in the 

corridor or region. 

 Generate corridor report - This action generates a report (.PDF 

file) containing information on accidents and safety in the region 
34  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

or corridor for each crossing. It contains the predicted annual 

accidents in the base and alternative cases from trains, highways 

and both combined. The report contains highway and train 

characteristics such as the make up of highway traffic and the 

speed of trains. 

 Generate HSR Report - This action generates a report (.PDF file) 

containing information on accidents and safety in the region or 

corridor for each crossing as produced by the HSR Model. It is 

similar to the corridor report discussed previously. 

Generate capital plan report - This action generates a pdf file (readable 

with Adobe Acrobat Reader) that shows the year-by-year capital 

expenditure and the crossing device status for each year of the alternative. 

This option only appears in the menu if you have checked (set to true) the 

option “Allow Capital Planning?” on the Settings page for the corridor or 

region. 

The Data Category Toolbar 

Crossing data are divided into several categories for viewing and 

modification. The data category toolbar is used to select the data 

category. Clicking on a button in the toolbar causes the selected data to 

be shown in the data grid at the bottom of the page. The data categories 

are explained below. 

Crossing Data Grid 

Use the data grid to view and modify crossing data. The following 

describes the data categories and the features of the data grid. 

Crossing Data Categories 

 General Information - The Crossings page contains general 

information about the crossing, locational factors and its physical 

characteristics. Using the mouse, click the Edit button and click 

on the field where you wish to enter data. 

 Devices - The devices data block includes the base and alternate 

warning device type and supplementary safety measures for the 

crossing are the "before" and "after" improvement crossing types, 

respectively. For “Base Device Type” and "Alternate Device 

Type", use the drop down lists. If your corridor or region allows 

capital programming, then you can set a Phase I and a Phase II 

alternate and you must specify the years of implementation for 

each. 

 Highway - The highway data category includes data entry boxes 

for the number of lanes, AADT and percentages of trucks (and of 

trucks, percent truck-trailers) and buses. The data category also 

includes pull-down menus where the user specifies the time-ofday traffic distribution for auto, truck and bus traffic. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  35

 Rail - In the rail data category the user specifies the number of 

tracks and train speeds. The user specifies the maximum 

timetable speed at the crossing and the average speeds traveled by 

trains of different types at the crossing. The regional model 

requires additional rail-related data inputs. 

 Costs - The cost data category contains the cost data for the 

crossing in the base and alternate cases. You can enter the data 

manually for each crossing, or you can use the default costs by 

selecting "Set default costs" from the Crossings link in the 

navigation menu. Additionally, you can specify whether you 

would like to set the default costs to the selected crossing or all of 

the crossings in the model. 

If a crossing device type is set to “Lights and Gates” and a 

supplementary safety measure is chosen, then the user can specify 

the costs for the supplementary measure in the appropriate boxes. 

 APS Model - This data category contains one data entry box for 

the number of accidents at the crossing in the preceding five-year 

period (for the Corridor Model) and five boxes for each year (for 

the Regional Model). It also includes a checkbox “Include 

Aggravating Factors?” If this is selected then the toolbar will 

contain a tab for “Aggravating Factors”, and aggravating factor 

variables will influence the calculation of predicted accidents and 

their severity. The other information on this section of the form 

is the predicted number of accidents for the crossing and the 

corridor (calculated based upon the data for the crossing and 

corridor). Predicted accidents are updated when the user presses 

the "Recalculate” link. The “Show chart” link provides the user 

with the “Crossing risk chart page” in a new window. This page 

has histograms containing the data found in the table found in the 

Crossings page. The rates and predicted accidents are calculated 

using the US DOT Accident Prediction and Severity Formulas 

and Resource Allocation Method (see the GradeDec.Net Model 

Reference and Documentation). 

 Aggravating Factors (Shown if “Include Aggravating 

Factors?” variable is checked in APS Model view) – The form 

for aggravating factors has as toolbar for selecting the base case 

or the alternate case for viewing and editing data. The form has 

two sections. The top section of the form specifies factors that 

affect accident occurrence and the bottom section specifies factors 

for accident severity. The aggravating factors result in a 

calculated score for occurrence between 0 and 60 and a score for 

severity between 0 and 60. The occurrence score will scale the 

predicted accidents down by 30 percent for a score of 0 and up by 

30 percent for a score of 60. Intermediate scores will linearly 

scale the predicted accidents between plus and minus 30 percent. 

The severity score will similarly scale up or down the number of 

predicted fatal and injury accidents. If the fatal and injury 
36  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

accidents are impacted by aggravating factors then the property 

damage only accidents will be calculated as the remainder from 

total accidents less the fatal and injury accidents. 

 HSR Model (Corridor Model Only) - This portion of the data 

entry form shows the predicted accidents using the High Speed 

Rail Model. The predicted accidents on this block of the form are 

updated when the user presses the "Recalculate” link. The “Show 

chart” link provides the user with the “Crossing risk chart page” 

in a new window. This page has histograms containing the data 

found in the table found in the Crossings page. 

“Edit, “Update” and “Cancel” Buttons 

You can modify the data for the selected crossing by clicking the “Edit” 

button: 

Note: For corridors, changing the milepost value to one that is 

identical to another crossing will result in the deletion of that other 

crossing when you click “Update”. 

Note: For regions, changing the crossing ID value to one that is 

identical to another crossing will result in the deletion of that other 

crossing when you click “Update”. 

After entering or modifying the data for a grade crossing, press the 

“Update” button to save the new data in the crossings database or the 

“Cancel” button if you do not wish to save the changes made. If you 

move to another crossing in the item list or exit the Crossing page 

without pressing the “Update” button or the “Calculate Predicted 

Accidents” button, you will lose any information that you entered since 

you last pressed “Update”. 

Note: Pressing the "Update" button does not recalculate the 

predicted accidents and rates based upon new or changed crossing or 

corridor data. In order to recalculate the rates and save them in the 

crossing database you must press the "Calculate Predicted 

Accidents" button. 

“View All” 

On the left side of the data table next to each item is a link that says 

“View All”. When you click this link a page will pop up that enables you 

to view and enter data for the item for all crossings in the corridor or 

region. This page has an “Edit” button that enables editing, and “Update” 

and “Cancel” buttons for saving and exiting edit mode. The page will 

display the item for 20 crossings at a time. If your corridor or region has 

more than 20 crossings, you can view and additional crossings in the 

corridor or region by using the paging feature in the lower left corner of 

the “View All” page. When you have finished making edits with this 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  37

page (don’t forget to click “Update” to save your edits) close this pop up 

page. 

Quick Import Page (invoked from the Crossings Page) 

Overview 

This page is invoked from the Navigation Menu Submenu under the 

Crossings option when the Crossings page is displayed. The Quick 

Import page pops up as a separate browser window. 

“Quick Import” allows the user to import data quickly from the National 

Grade Crossing Inventory into your selected corridor or region. In order 

to use “Quick Import” you need to know the FRA IDs of the grade 

crossings that you seek to import. Unlike the “Import Page”, with “Quick 

Import” you cannot select crossings by geographic location and you 

cannot screen the imported crossings according to a number of criteria. 

Features 

There are two methods for employing “Quick Import”, one is by entering 

up to five grade crossing IDs, and the other is importing based on a list 

that is stored in a text file. You select which of these two methods to use 

by: 

Option 1 - Enter Up to Five IDs 

Figure 10 View of Quick Import Page 

Use this option to enter up to five grade crossings. Enter the FRA grade 

crossing IDs into the boxes. Check the box if you want GradeDec.Net to 

calculate predicted accidents for the imported grade crossings. Click 

“Import Crossings” after you have entered the information. 
38  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

Option 2 - Import List 

Figure 11 View of Import List 

Use this option to import any number of grade crossings for which you 

know the FRA grade crossing IDs. Prepare a comma separated value 

(CSV) file that contains a list of grade crossing IDs to import from the 

National Grade Crossing Inventory of Public Highway-Rail Grade 

Crossings. Along with each crossing ID, the list should specify a rank 

value. 

The file should contain column headers in the first row (Rank and ID) 

followed by successive rows with the rank and the ID of each crossing to 

import. The rank value and its column header must be followed 

immediately by a comma. For instance, the Sample List File on the right 

shows the contents of a file with five grade crossings to import. 

You can create the CSV file using a text editor like Notepad, or by 

creating a spreadsheet with your list of crossings and saving it as a CSV 

file. 

Use the “Browse” button to select the CSV file that you have prepared. 

Click the “Import Crossings” button after you have entered the 

information. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  39

4.1 Import Page 

Figure 12 View of Import Page 

Overview 

Use this option to enter up to five grade crossings at a time. 

The purpose of this page is to enable the analyst to import data from the 

National Inventory of Highway-Rail Grade Crossings database into 

GradeDec.Net for analysis. The page lets the user build a query based on 

geography, identified corridors and grade crossing characteristics. The 

page also enables the specification of automatic mapping to 

GradeDec.Net fields. The following sections describe the different parts 

of the page and their functions. You can use this option repeatedly to 

import more than five crossings. 

Features 

Importing Data from the National Inventory of Grade 

Crossings 

When the Import page opens in the browser use the following drop down 

lists to select the region under consideration: 

"Select a State", “Select a County”, “Select Area” 

Choose the state first and then the county from the respective lists. After 

selecting the county, you should select an area, which is an area within 

the county (i.e., “the whole county”, a specific city, or “not in any city”). 

After selecting the area, it will appear in the “Selected Areas” data grid. 

For Corridor Model 

After selecting the areas for inclusion, use the item list to select crossings 

that are identified as being in a specific corridor, using the shift or ctrl 
40  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

keys to make multiple selections. After making this selection, the records 

from the Grade Crossing Inventory to be imported will be viewable in the 

data grid at the bottom of the page. 

For Regional Model 

After selecting the areas for inclusion the records from the Grade 

Crossing Inventory to be imported will be viewable in the data grid at the 

bottom of the page. 

Press the “Delete” link in the “Selected Areas” data grid to delete a 

selected area. 

Criteria 

The “Criteria” section allows the user to restrict the crossings to import to 

those that meet specific criteria. The criteria include: average annual 

daily traffic, number of trains per day and number of accidents in the 

previous 5 years. 

Note: While GradeDec.Net allows you to import records that have no 

train or highway traffic, be aware that the absence of either at a grade 

crossing will cause a computational error in the model (e.g., divide by 

zero). To avoid this, you should either exclude crossings with no traffic, 

or enter data manually for these crossings (assuming that this reflects 

actual conditions at the crossings). 

Import Options 

Use this section to determine the automated filling of GradeDec.Net

fields when importing data. You can specify to use default cost data, or 

leave cost data blank for manual data entry. The base grade crossing type 

is the type specified in the National Inventory of Highway-Rail Grade 

Crossings database. The alternative grade crossing type can be 

automatically designated using the pull-down menus, or the user can 

specify that alternative crossing types will be manually entered. 

Import Crossings Data 

By clicking on the button “Import Crossings Data”, the selected records 

are imported to the selected corridor or region, and your browser transfers 

to the Crossings page. The instructions that you specified in the Import

page for automatic field fill are executed and the new data records are 

appended to the existing records in the selected region. After importing, 

predicted accidents are calculated for all crossings as well as a summary 

for the corridor or region. 

If upon importing data a record already exists with the same crossing ID 

as a newly imported crossing, the existing record in the region is 

overwritten by the imported data. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  41

5.1 Scenario Page 

Figure 13 View of Scenario Page 

Overview 

The Scenario Input Screen is where you view and edit scenario data for an 

analysis. Scenario data for a model input variable can be either a fixed 

value or several values that describe a probability distribution. 

Probability distributions are used to derive analysis results with Monte 

Carlo simulation. For a discussion of simulation see the section “About 

Simulation” in section “7.1 Simulation Page”. 

This page possesses a number of features that let you easily visualize data 

and quickly develop probability distributions that best reflect available 

information and judgments on operations, future developments and social 

costs. These features include: 

 Ease of navigation among variables 

 Instant viewing of statistics and charts 

 Instant validation and saving of ranges 

GradeDec.Net can store many different scenarios for analysis. Scenario 

data categories include: rail operations, highways, social costs and price 

inflation. Scenarios are initially defined and selected in the Settings page 

(change to the Scenario view clicking the “Scenario” button in the 

“Viewing in table below the selected” line of the Settings page). 

Remember that the data in the selected scenario are the data that will be 

used by the GradeDec.Net model to conduct the benefit-cost analysis on 

the strategies and cases defined elsewhere in the model. If you wish to 

work with data from another scenario and use that data in the analysis, 

that scenario must be selected from the Settings page (see section above 

on the Scenario page). You can vary the baseline assumptions for an 

analysis by creating multiple scenarios (for instance, one each for high, 

moderate and low traffic growth). 
42  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

Features 

The Scenario page is shown above. The scenario input variables in 

GradeDec.Net are organized into data groups according to a functional 

classification. The data groups are: 

 Rail Operations 

 Highway 

 Social Costs 

 Price Inflation 

When you link to the Scenario page the Rail Operations sheet is loaded 

and the first variable in that sheet is selected and shown in the chart and 

tables. You browse among the different sheets using the drop down list 

in the upper right-hand corner of the form. 

The remainder of this section describes each component of the Scenario

page and their functions. 

Data Group Pull Down List 

Use this drop down list on the left side of the upper toolbar to select the 

data group to view and edit. 

The data groups accessible from the Scenario page offer the analyst great 

flexibility in specifying the present and future travel, cost, and policy 

environment that will affect a project. The content of the major groups 

are summarized below. Note that each data group allows the analyst to 

specify a range of uncertainty around any of the values entered for that 

group (see the Variable Data Grid below). 

 “Rail Operations” and “Highway” data on this page (see 

Figure 13) interact with other model variables set on the 

Settings and Crossings pages to determine: the levels of rail 

and highway traffic; user costs, and benefits. 

 “Social costs” data are entered in this Scenario page view. 

Most of the cost items (including discount rate, value of travel 

time, value of statistical life and injury, etc.) are selfexplanatory and are set to default values taken from FRA

sources, but can be edited by the user. 

 The “Price Inflation” view includes data growth rates for 

general price inflation by year and growth rates for fuel price 

inflation by year. A real fuel price index is calculated from 

the nominal fuel price index divided by the general price 

index. The real fuel price index is applied to the fuel and oil 

components of the vehicle operating costs. All other cost and 

benefit components of the analysis are unaffected by inflation 

(i.e., future streams are calculated in terms of constant dollars 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  43

and relative prices excluding fuel and oil are assumed to 

remain constant). 

Generate scenario report (Invoked from the 

Navigation Menu Submenu) 

This feature generates a report in pdf format (readable with Adobe 

Acrobat) of the Scenario page. Use this feature by selecting “Generate 

scenario report” from the Scenario option in the Navigation Menu on the 

left side of the page. 

Edit Distribution 

This feature allows for the distributions to be changed for each of the 

variables on the page. The probability distributions and their 

corresponding input values are described below. For each scenario input 

variable, you can specify a probability distribution. The choice of 

probability distribution type and the input values for the distribution 

determine the probability distribution for the input variable. 

For each scenario input variable, you can specify a probability 

distribution. The input values and the choice of probability distribution 

type determine the probability distribution for the input variable. 

After clicking “Edit” the types of probability distributions that appear in a 

drop down list and from which you can choose are: 

 Fixed Value (single input value required) - When you choose 

fixed value, there is no distribution and the variable assumes a 

single, fixed value in a simulation. For a fixed value, no statistics 

are shown and only the middle percentile box is enabled for data 

entry. No chart is shown for a fixed value.

 Skewed Bell (three input values required – 10, 50 and 90 

percentiles) - The skewed bell distribution is derived from three 

points: the 10% lower value, the 50% value (or, median) and the 

10% upper value. For non-skewed input values (e.g., the 

distances between the median and the lower and upper values are 

equal) the distribution is normal. This distribution is useful when 

the exact form of the distribution is not known yet good estimates 

on the median and boundary values are available. 

 Normal (two input values required – mean and standard 

deviation) - Use this distribution type when you have data 

indicating the variable is non-skewed and normally distributed. 

 Uniform (two input values required – maximum and 

minimum) - With the uniform distribution every point on an 

interval is equally likely. Minimum and maximum input values 

are required for this distribution. 
44  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

 Triangle (three input values required – maximum, minimum 

and mode) - All values for this distribution lie between the 

minimum and the maximum and its density function forms a 

triangle with its peak at the mode. Use this distribution when the 

variable and data indicate firm bounds on the maximum and 

minimum values and a most likely value. 

When editing the distributions the page displays the “Update” and 

“Cancel” buttons, which are used to save or discard the edits you have 

made to the variable distributions. 

Edit Values 

This feature allows you to edit the values that define the probability 

distribution for the variable. For each distribution type (including “Fixed 

Value”) there will be either one, two or three values that define the 

distribution. When editing values there will be headings and text boxes 

that correspond to the distribution for each variable (see Table 5). When 

editing the values the page displays the “Update” and “Cancel” buttons, 

which are used to save or discard the edits you have made to the variable 

distributions. 

Table 5 Probability Distributions and their Displays on the Scenario 

Page 

Probability

Distribution

First Value Second 

Value

Third Value

Fixed Value Fixed value

Uniform Minimum value Maximum value

Skewed Bell 10th percentile 50th percentile 90th percentile

Normal Mean Standard Deviation

Triangle Minimum value Mode Maximum value
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  45

Scenario Input Variable Chart 

 Figure 14 View of Scenario Input Variable Chart 

Overview 

Clicking on “View” for a variable on the Scenario page will cause the 

scenario input variable chart to pop up, showing a chart and data for the 

selected variable. The page contains a chart, a summary statistics table, a 

percentiles table and option buttons for selecting alternative chart types. 

For a fixed value, the chart will display the message “No Chart for Fixed 

Value” and the tables will reflect the information for the single, fixed 

value. 

There are three chart types and each shows a shaded region that 

represents the 80% confidence interval. A dotted red line marks the mean 

value of the distribution. 

The x-axis on all the charts ranges between the values whose probabilities 

are 0.1 and 99.9 percent, respectively. The different chart types are 

selected using the option buttons below the chart (click “Refresh” after 

making a selection). 

Features 

Density/Cumul/De-Cumul option buttons 

The selected option determines which of the three chart formats: 

 Probability density 

 Cumulative probability 

 De-cumulative probability 
46  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

are displayed for the selected variable (see the Glossary for definitions). 

Summary statistics tables 

The summary statistics frame displays the mean, mode, and standard 

deviation of the distribution. See the glossary for the definitions. 

Percentiles 

The percentiles frame displays the percentiles of the input distribution. A 

percentile indicates the probability that the value of the input variable 

would fall below the given value of the x-axis. For instance, in Figure 17, 

the chance that the sampled input value of “the rate of growth in 

passenger traffic, near term, %”, would fall below 3.3 is 90 percent, given 

the distribution specified by the users. 

6.1 Parameters Page 

Figure 15 View of Parameters Page 

Overview 

The Parameters page is where you can view and modify model 

parameters and other data values in GradeDec.Net. Parameters include: 

 Vehicle emission coefficients; 

 Fuel and oil burn coefficients 

 Effectiveness rates, and, 

 High-speed rail model coefficients 

Other data include: 

 Traffic time-of-day distributions 

 Default costs of grade crossing devices 

 Default costs of supplementary safety devices 

See the GradeDec.Net Model Reference for additional explanations. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  47

The page enables the user to access model parameters other data values 

for reference and for editing, if necessary. In most applications it is 

unlikely that you will wish to modify the emission and fuel burn 

coefficients. You may wish to modify or add to the time-of-day traffic 

distributions if localized information is available that better characterizes 

these distributions. There may well be local guidance on grade crossing 

operating and maintenance costs and these should be modified as needed. 

7.1 Simulation Page 

Figure 16 View of Simulation Page 

Overview 

Use the Simulation page to set the simulation parameters and begin a 

simulation. You should browse to this page only when you are ready to 

conduct a simulation, that is, after having made all required modifications 

to data, and after having selected the corridor (or region), scenario and 

results file. 

In the data grid, note that the items “Reallocate traffic if grade 

separated?” and “Use the HSR Model” appear only with the corridor 

model and not with the regional model. 

You also have the option of selecting the results that will be reported 

upon completion of the simulation page. 

Features 

The Simulation page is used to run a simulation. Use the page to set the 

simulation parameters and initiate the simulation. The simulation 

parameters are discussed below. 

About Simulation 

GradeDec.Net uses simulation, or risk analysis, to generate result 

forecasts. By specifying probability distributions for scenario inputs, the 

user quantifies their variability and uncertainty. The impact of this 
48  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

uncertainty on the outcomes, as reflected in the GradeDec.Net analytic 

model, is quantified using simulation. 

With simulation, rather than solving the model once using "best guess" 

values for inputs, GradeDec.Net solves the model for many independent 

trials. In each trial, a random sample is taken from the distribution of 

each scenario input. Each trial produces an outcome (i.e., a set of values 

for the result variables) that is as likely to be achieved as any other. By 

applying statistical analysis to a set of outcomes, GradeDec.Net derives 

descriptive statistics for each result variable. Thus, for instance, 

GradeDec.Net will tell us not only that "the answer is 50", but also that 

"with 90% probability the answer lies between 30 and 75". As opposed 

to point estimates or sensitivity analysis (where one variable is arbitrarily 

varied), risk analysis supports better decisions by explicitly reporting the 

probability distributions of the results. 

Also see the section “Why GradeDec.Net?” in the Introduction. 

Data Grid Items 

The following describes the items found in the table of the Simulation

page. Click the “Edit” button to make the appropriate modifications to 

the existing values. 

“Run central values only” 

Check this box to run your model using only the central values. The 

reported results will be point values without probability ranges. When 

this box is checked, the trials box and random seed box are disabled. 

Choosing this option will result in a minimum run time and is useful 

when analyzing large corridors or regions. 

“Discount carbon dioxide at 3 percent?” 

Selecting this option will discount carbon dioxide emissions savings 

using a three percent discount rate. All other benefit and cost components 

in your analysis will be discounted (regardless of whether this feature is 

selected) using the discount rate that you set in the Scenario Page (under 

the Social Costs section). This feature allows for future year benefits from 

carbon dioxide emissions reduction to be valued more highly than if using 

a higher discount rate. Higher discount rates cause outyear flows to 

diminish more rapidly than with a lower rate. 

”Number of Trials” 

Enter the number of trials for the simulation. The number of trials is the 

number of times that the program will sample from the scenario input 

distributions, solve the model and generate results. More trials will yield 

more stable results and will take more time to run. While a number of 

factors will determine the minimum number of trials needed to achieve 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  49

stable results, 500 trials will almost always be adequate. You must use at 

least 3 trials to run a simulation. 

Recommended Practice: To save time, when testing your data and 

assumptions, use a small number of trials (50 or less). When you are 

satisfied that there will be no more changes to the data, run a simulation 

with a large number of trials to arrive at your final result. 

Expert Option: The user can select Latin Hypercube, the default, as the 

simulation method, or, alternately, the user can select the regular Monte 

Carlo method for simulation via the “Sampling Method” item. Latin 

Hypercube is a stratified sampling method and will usually converge to 

the true result distribution with fewer trials than the Monte Carlo method. 

If you wish to know more on this subject, a good technical reference is 

"Latin Hypercube sampling (A Program Users Guide)", by R.L. Iman 

J.M. Davenport and D.K. Zeigler, Technical Report SAND79-1473, 

Sandia Laboratories, Albuquerque (1980) 

“Sampling Method” 

See “Expert Method” in the description for “Number of Trials”. 

“Random Seed” 

The random seed determines the sequence of pseudo-random numbers 

that are generated by the simulation engine. Any positive integer value 

will generate a unique sequence of pseudo-random numbers for the 

simulation. Two simulations with identical data, number of trials and 

random seed will generate identical results. 

Changing the random seed is an expert option. You may want to change 

the random seed to test the effects of the randomness of the sampling on 

the result distributions. 

“Run Risk Sensitivity Analysis?” 

The risk sensitivity analysis, which is executed after the simulation, runs 

the GradeDec.Net model with all the input variables except one set to 

their mean values. The exception input variable is set to its 10 percent 

lower value and the model is solved. This input variable is then set to its 

10 percent upper value and the model is solved again. This process is 

repeated for all input variables. The results of the sensitivity analysis are 

displayed in the tornado chart, which is invoked from the Results page. 

By leaving this box unchecked, and thus the value false, your results file 

will not contain values for the tornado chart. When there are numerous 

grade crossings in a region or corridor, the risk sensitivity analysis 

can greatly increase the time required to run a simulation. You may 

prefer to sacrifice the risk sensitivity analysis in favor of shorter run times 

by not checking the box. 
50  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

"Reallocate Traffic If Grade Separated?" 

This item appears on the Simulation page only when using the corridor 

model. In the GradeDec.Net corridor model, there is an algorithm that reassigns highway traffic from the adjacent grade crossings to an improved 

crossing with grade separation. This box is checked by default making its 

value true and by removing the check you choose to run your simulation 

without the re-assignment of traffic. 

"Use the HSR Model?" 

This item appears on the Simulation page only when using the corridor 

model. If this box is checked, then the simulation uses the HSR model 

algorithms to calculate the safety improvements (i.e., risk reduction) at 

the crossings. By default, when this box is unchecked, the model uses the 

algorithms specified by the US DOT Accident Prediction and Severity 

Model. The GradeDec.Net Model Reference and Documentation 

presents a fuller description of the models and their modes of usage. 

8.1 Results Page 

Figure 17 View of Results Page 

Overview 

The results of a simulation are viewed in the Results page. When you 

browse to the page it displays the benefit and benefit-cost summary result 

group with the associated variables. 

When a simulation completes, the browser automatically redirects to this 

page. 

The purpose of this page is to navigate, view and print results and their 

associated tables and graphics. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  51

Features 

Navigating the Results 

You navigate among the results by selecting the result variable group 

with the drop down list in the upper left-hand corner of the screen. After 

selecting the result variable group, use the up and down buttons in the 

toolbar to find the variable of interest. Alternatively, you can scroll or 

point-and-click to the variable of interest in the results data grid at the 

bottom of the page. 

The results categories are: 

 Benefits and Benefit-Cost Summary 

 Benefits by Crossing – Safety 

 Benefits by Crossing – Travel Time Savings 

 Benefits by Crossing – Environmental (emissions reduction) 

 Benefits by Crossing – Vehicle Operating Cost Savings 

 Total Benefits by Crossing 

 Total Costs by Crossing 

 Intermediate Safety Results 

 Intermediate Non-Safety Results 

 Salvage value by crossing 

 Maximum queue length, first year, by crossing 

 Maximum queue length, last year near term, by crossing 

 Maximum queue length, last year, by crossing 

The summary shows the results of the analysis for the analysis period in 

thousands of present value dollars for all crossings. The intermediate 

safety results show the reduction in predicted accidents by accident type 

category (fatal, injury, property damage only) for the selected years (first, 

last year near term and last). The intermediated non-safety results show 

the reduction in delay and fuel consumption in each of the selected 

years. The other result categories show metrics for each crossing. The 

maximum queue length results show the maximum vehicle queue at the 

crossing for the base case device in the selected year. 

“View” link 

In the data grid at the bottom of the Results Page, next to each results 

variable is a “View” link. If you click the “View” link, a new browser 

window pops up with the “View results table and chart” page, which 

displays: a chart with options, a statistical summary, and a percentiles 
52  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

table for the selected results variable. The “View results table and chart” 

page is described in the following section. 

 “Show Summary Chart” link 

This link is found near the top of the Results page. Clicking this link 

pops up a new browser window with the “Benefit-costs chart page”. This 

page displays charts on the benefits, costs and ranking of the crossings by 

benefit. See the section titled “Benefit-costs chart page” for more details. 

Navigation Menu Submenu 

Access the Navigation Menu Submenu from the Navigation Menu (on the 

left side of the page under the “Results” option). The following describe 

the components of the menu. 

 Generate results report - This action generates a report (.PDF file) 

containing all of the information that is accessible from the results 

page. The results report shows the summary statistics and 

percentiles for every result variable. 

 Download results to a CSV file – Use this feature to download all 

of the simulation results to a CSV (comma separated values) file. 

The CSV file can be read into MS Excel or other spreadsheet 

software. 

View results table and chart 

 Figure 18 View of Results Variable Chart 

Overview 

Clicking on “View” for an item in the data grid on the Results page will 

cause the “View results chart and table” page to pop up. The page 

contains a chart, a summary statistics table, a percentiles table and option 

buttons for selecting alternative chart types. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  53

For a fixed value, the chart will display the message “No Chart for Fixed 

Value Result” and the tables will reflect the information for the single, 

fixed value. 

There are three probability distribution chart types and each shows a 

shaded region that represents the 80% confidence interval. A dotted red 

line marks the mean value of the distribution. A fourth chart type is the 

tornado chart, which is displayable only if the user selected the “Run risk 

sensitivity analysis” option form the Simulation page. 

The x-axis on all the charts ranges between the minimum and maximum 

values of the simulation trials. The different chart types are selected 

using the option buttons below the chart (click “Refresh” after making a 

selection). 

Features 

Histogram/Cumul/De-Cumul/Tornado option 

buttons 

The selected option determines which of the three chart formats to 

display: 

 Histogram; 

 Cumulative probability; 

 De-cumulative probability; or, 

 Tornado (option available only if the risk sensitivity option 

was selected when you ran the simulation) 

Histogram, Cumulative probability chart and De-cumulative 

probability chart 

When you browse to this page a histogram chart of the first result variable 

is displayed with its values distributed into 20 probability bins. You can 

modify the granularity of the histogram by changing the number of bins 

using the “Bins” box in the toolbar. 

Choose the “De-cumul” option button to view the de-cumulative 

probability chart. This chart shows the full range of values for the 

selected result and the probability of exceeding each value in its range. 

The cumulative probability chart is displayed when you press the 

"Cumulative" option button on the form. 

Click the “Refresh” button after making selections. 

Tornado chart 

An input variable contributes to risk by means of: a) its own variance, 

and, b) its structural role in the GradeDec.Net model. For instance, an 

input variable with large variance may not be a significant contributor to 

the risk of a result while an input variable with small variance may cause 
54  GradeDec.Net Page-by-Page GradeDec.Net Users' Manual 

the result to be very uncertain and risky. Without the analysis of risk 

sensitivity it is not easy to determine which factors are the significant 

contributors to the riskiness of a particular result. 

The tornado chart shows the impact of each random variable input factor 

when all the other input factors are set to their mean values and the single 

input factor is allowed to vary within its 80% confidence interval. The 

tornado chart displays in order the ten input variables that are the major 

contributors to the risk of a result. 

This analysis of sensitivity can guide the analyst to focus on refining the 

estimates on the range of input variables that truly matter, and help 

decisions makers plan for mitigating risks. 

Figure 19 A Tornado Chart 

Number of Bins 

Select the number of bins for the histogram chart. You may choose a 

value between 10 and 100. Click the “Refresh” button after making a 

selection. 
GradeDec.Net Users' Manual GradeDec.Net Page-by-Page  55

Benefit-Cost Charts 

Figure 20 View of Benefits and Costs Summary Chart 

Overview 

The Benefit-cost chart pops up in a new browser window by clicking the 

“Show summary chart” link near the top of the Results page. 

This page contains several charts that illustrate the benefits, costs and the 

rankings of the crossings by benefits. The user can choose to rank 

crossings either by safety benefits only or total benefits. 

The charts on this page are designed to support resource allocation 

decisions. The charts illustrate the relative magnitude of benefits, how 

the ranked crossings compare with one another and the cumulative 

benefits from crossing improvements. 

One chart also compares the ranked benefits by crossing with the costs by 

crossing. This view of the benefits and costs assists users to quickly 

identify high yield improvements and to develop improvement programs 

accordingly. 

GradeDec.Net Users' Manual Glossary of Terms  57

Glossary of Terms 

Bins 

The range for a simulation result variable, that is, the values bounded by 

its minimum and maximum values, is divided into equal portions called 

bins. The result value from each trial "falls" into one of these bins. 

Charting the result value's range on the horizontal axis and the probability 

of a result value falling in the bins yields the histogram chart. 

Cumulative Probability Distribution 

A cumulative probability distribution is constructed by cumulating the 

frequency of the probability density function. A cumulative probability 

distribution is an "upwardly sloping" curve, where each point on the 

curve gives the probability that the variable will be equal to or less than 

the value on the x-axis. The y-axis of the cumulative probability 

distribution ranges between 0 and 1. The cumulative probability 

distribution equals zero for a variable's minimum value and rises to 1 at a 

variable's maximum value. 

De-Cumulative Probability Distribution 

A de-cumulative probability distribution is constructed by subtracting (or 

de-cumulating) a variable's probability frequency starting with a 

probability of 1. A de-cumulative probability distribution is a "downward 

sloping" curve, where the curve gives the probability of the variable 

exceeding the value along the X-axis. The de-cumulative probability is 1 

for a variable's minimum value and is 0 for its maximum value (i.e., the 

y-axis ranges between 1 and 0). 

Deterministic 

The term deterministic indicates that there is no uncertainty associated 

with a given value, variable or model. Models that include random 

variables are called stochastic. 
58  Glossary of Terms GradeDec.Net Users' Manual 

Histogram 

A histogram shows the frequency of a discrete random variable and is 

used to display the frequency distribution of Monte Carlo simulation 

result variables. In a histogram, the result values are gathered in bins and 

the height of the bars correspond to the frequency with which values fall 

in the respective bins. 

Kurtosis 

Kurtosis is a statistical measure of a distribution's peakedness. Flatter 

distributions (with thin tails) are called platykurtic and peaked 

distributions (with fat tails) are called leptokurtic. The formula for 

kurtosis is: 

where 

x

is the mean of the observations, s is the standard deviation and n 

is the number of observations. 

Latin Hypercube 

Latin Hypercube is an alternative statistical sampling method to the 

Monte Carlo method. This is a stratified sampling method, which means 

that the range for each input variable is divided into strata and one 

random sample is taken from each stratum. This method ensures faster 

convergence to the result distribution than with the Monte Carlo 

sampling method. 

Lower 10% Value 

The lower 10% value is the 10th percentile value and is the lower limit of 

an 80% confidence interval as input by the user. 

Mean Value 

The mean value for a collection of observations of a random variable is 

its expected value and equals the sum of the observations divided by the 

number of observations. For skewed distributions, the mean value is off 

the median value and is located in the direction of the distribution's skew. 

Median Value 

The median value is the 50th percentile: there is equal probability that the 

value for a random variable will lie above or below the median. 

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GradeDec.Net Users' Manual Glossary of Terms  59

Mode 

The mode of a probability distribution is the value for which the 

probability density function is at a maximum. The value has the highest 

probability (and is sometimes called "the most likely value", not to be 

confused with the mean or expected value). 

Monte Carlo 

Monte Carlo is the method of sampling from random variables by taking 

a random number on the 0-1 interval , call it a, and finding the value of 

the random variable whose cumulative probability equals a. Repeated 

Monte Carlo sampling on a number of random variables that are inputs to 

a model and repeatedly solving the model to arrive at probability 

distributions for the result variables is called Monte Carlo simulation. 

Probability 

Probability is the likelihood of the occurrence of a value or event. 

Probability Density Function 

Same as probability distribution. 

Probability Distribution 

A probability distribution or probability density function shows a 

continuous random variable's frequency of occurrence over its range. 

Random seed 

The random seed is a number that initializes the generation of random 

numbers used in a Monte Carlo simulation. For the same random seed 

and the same number of trials given no change in the model or inputs, the 

results of two Monte Carlo simulations will be identical. 

Risk 

The term refers to uncertainty in a forecast outcome. Colloquially, risk is 

often associated with undesirable or downside outcomes (as in "hedging 

against risk"). In a risk analysis, risk is reflected in the probability 

distributions of result variables. 

Risk Analysis 

Risk analysis is a term applied to several methods for quantifying 

uncertainty in forecasts. The risk analysis method used in GradeDec 

2000 is called Monte Carlo simulation.
60  Glossary of Terms GradeDec.Net Users' Manual 

Simulation 

Simulation is a numeric method for finding solutions to analytically 

complex problems by "simulating" repeated, real world occurrences. 

Skewness 

Skewness is a measure of the asymmetry of a distribution. The 

probability density function of a skewed distribution has a longer tail on 

its skewed side. A right skewed distribution has skewness greater than 0 

and a left skewed distribution has skewness less than 0. The formula for 

skewness is: 

where is the mean of the observations, s is the standard deviation and n 

is the number of observations. 

Standard deviation 

The standard deviation, which is the square root of the variance, is the 

principal descriptive statistic after the mean value. Knowing only a 

distribution's mean value and standard deviation, an upper bound can be 

found on the probability of any value in a variable's range. The standard 

deviation reported for the results is the sample standard deviation, given 

by the formula: 

where n is the number of trials. 

Trial 

A trial is one solution of a model in a simulation. A simulation consists 

of many trials. In each trial, every input variable is populated with a data 

value sampled from the variable's probability distribution. 

Upper 10% Value 

The upper 10% value is the 90th percentile of a probability distribution 

and the upper limit of an 80% confidence interval. 

Variable 

A variable is a model element that can assume more than one value. A 

fixed-value input variable can assume only one value. A random variable 

can assume a range of values according to its probability distribution. 

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GradeDec.Net Users' Manual Glossary of Terms  61

Variance 

The variance is a measure of the dispersion of values in a probability 

distribution, and is a measure of risk. The variance is the average of the 

squared deviations about the mean. The variance gives disproportionate 

weight to "outliers," values that are far away from the mean. The 

variance is the square of the standard deviation. 

GradeDec.Net Users' Manual Index  63

Index 

A

AADT 34 

alternate case 32, 35 

archive 29 

B

base case 35, 51 

benefit-cost 1, 2, 21, 41, 50 

summary 40, 45, 46, 50, 51, 52, 55 

C

chart 

histogram 35, 36, 53, 54 

corridor 1, 2, 3, 11, 15, 17, 18, 19, 27, 28, 30, 

32, 33, 34, 35, 36, 37, 39, 40, 47, 49, 50 

corridor model 15, 47, 50 

D

data group 42 

dataset 13, 14, 15, 17, 18, 27, 28, 29 

default values 6, 14, 20, 21, 42 

demand 2 

device 8, 11, 15, 17, 19, 34, 35, 51 

discount rate 42, 48 

discounting 1 

distributions 2, 15, 18, 21, 41, 43, 44, 46, 47, 48, 

49 

E

economic 1, 2 

emissions 11, 15, 48, 51 

F

FRA 3, 6, 7, 33, 37, 38, 42 

G

gates 32 

grade crossing 1, 2, 3, 6, 11, 15, 30, 33, 36, 37, 

38, 39, 40, 46, 47, 49, 50 

grade separation 50

H

high speed rail 15 

HSR 2, 31, 34, 36, 47, 50 

L

lanes 34 

last year 15, 20, 51 

last year near term 20, 51 

Latin Hypercube 49 

M

manage 26 

Monte Carlo 41, 49 

N

net present value 3 

normal 20, 43 

O

operating and maintenance costs 47 

P

parameters 6, 15, 17, 21, 46, 47 

percentile 43, 44, 46 

period of analysis 

base year 32 

end year 15, 20 

R

random seed 48, 49 

region 1, 2, 3, 11, 15, 17, 18, 27, 28, 30, 32, 33, 

34, 36, 37, 39, 40, 45, 47, 49, 53 

regional model 15, 35, 47 

registration 25 

results set 16, 17, 20, 27, 28 
64  Index GradeDec.Net Users' Manual 

risk analysis 2, 12, 21, 47, 48 

trial 48 

S

safety 2, 3, 11, 12, 15, 19, 20, 31, 33, 34, 35, 46, 

50, 51, 55 

scenario 15, 16, 17, 20, 27, 28, 41, 42, 43, 45, 

47, 48 

Simulation 16, 17, 21, 41, 43, 47, 48, 49, 50, 52, 

53 

skewed bell 20, 43 

social costs 20, 41 

start year 15 

T

tornado chart 3, 49, 53, 54 

traffic distributions 18, 47 

traffic management measure 11 

travel time 2, 42 

triangle 20, 44 

U

uniform 20, 43 

user costs 11, 42 

V

vehicle operating costs 2, 3, 11, 42