Calculator Guide

Learn how to use the Calculator to estimate how emissions change when you adjust transportation activity measures like vehicle miles traveled (VMT), vehicle counts, and other factors.

What is the Calculator?

The Calculator is an interactive tool that lets you:

  • Adjust activity measures (VMT, vehicles, starts, hours, etc.)
  • See how emissions change in real-time
  • Compare baseline emissions vs. adjusted scenarios
  • Estimate the impact of transportation changes
  • Visualize emissions changes with interactive charts

This is useful for:

  • Scenario planning: "What if we increase VMT by 10%?"
  • Policy analysis: "How do emissions change with more electric vehicles?"
  • Conformity analysis: Estimating emissions for transportation plans

Accessing the Calculator

  1. Click "CALCULATOR" in the sidebar (MENU section)
  2. Or click "Calculator" from the Welcome page under "Explore Your Data"
  3. The Calculator page will load

Understanding the Interface

The Calculator has several main sections:

  1. Selection Panel: Choose geographic area, pollutant, and activity measure
  2. Data Table: Editable table showing activity measures
  3. Results Display: Shows emissions estimates and comparisons
  4. Charts: Visual displays of emissions changes

Step-by-Step: Using the Calculator

Step 1: Select Geographic Area

  1. In the "Table" dropdown, select a geographic area (county)
    • Options include counties from the CAT Grand Database
    • Example: "Tompkins County, NY"
  2. The system will load default MOVES activity data for that area

Step 2: Select Pollutant

  1. In the "Pollutant" dropdown, select the pollutant you want to analyze:
    • CO2e: Carbon dioxide equivalent
    • CO: Carbon monoxide
    • NOx: Nitrogen oxides
    • And others
  2. Different pollutants will show different emission factors

Step 3: Select Activity Measure

  1. In the "Activity Measure" dropdown, select what you want to focus on:
    • Options may include vehicle types, fuel types, road types, etc.
  2. This determines which columns are most relevant in the data table

Step 4: Review Baseline Data

The Data Table will automatically populate with default MOVES values for your selected area and pollutant. You'll see columns like:

  • Year: The year being modeled
  • VMT: Vehicle miles traveled
  • Vehicles: Vehicle count
  • Starts: Number of vehicle starts
  • Hours: Operating hours
  • Vehicle Type Percentages: % Bus, % Car/Motorcycle, % Light Truck, etc.
  • Fuel Type Percentages: % Gas, % Diesel, % Electric, etc.
  • Road Type Percentages: % Rural Restricted, % Urban Unrestricted, etc.

Note: These are default values from the MOVES model. You can edit them to create custom scenarios.

Step 5: Adjust Activity Measures

To create a scenario, edit values in the table:

  1. Click on a cell in the table to edit it
  2. Enter a new value
  3. Press Enter or click elsewhere to save
  4. The Calculator will automatically recalculate emissions

Example Adjustments:

  • Increase VMT by 10%: Multiply current VMT by 1.1
  • Add more electric vehicles: Increase % Electric, decrease % Gas
  • Change vehicle mix: Adjust vehicle type percentages
  • Modify road usage: Change road type percentages

Step 6: View Results

The Results Display shows:

  • Baseline Emissions: Original emissions based on default values
  • Adjusted Emissions: New emissions based on your edits
  • Difference: How much emissions changed (absolute and percentage)
  • Comparison Charts: Visual displays comparing baseline vs. adjusted

Step 7: Explore Charts

Interactive charts show:

  • Emissions by category (vehicle type, fuel type, etc.)
  • Comparison between baseline and adjusted scenarios
  • Breakdowns showing where changes occurred

Interacting with Charts:

  • Hover: See exact values
  • Click: Filter or highlight categories
  • Zoom: Some charts allow zooming

Understanding the Calculations

How It Works

The Calculator uses the MOVES (Motor Vehicle Emission Simulator) model to estimate emissions:

  1. Activity Data: Your edited values (VMT, vehicles, etc.)
  2. Emission Factors: Standard MOVES emission rates
  3. Calculation: Activity × Emission Factors = Emissions
  4. Real-time Updates: As you edit, calculations update automatically

Key Concepts

VMT (Vehicle Miles Traveled)

  • Total miles driven by all vehicles
  • Increasing VMT generally increases emissions
  • Can be adjusted by vehicle type, road type, etc.

Vehicle Counts

  • Number of vehicles in the fleet
  • Affects total activity and emissions

Vehicle Type Distribution

  • Percentage of different vehicle types (cars, trucks, buses, etc.)
  • Different types have different emission rates
  • Changing the mix changes total emissions

Fuel Type Distribution

  • Percentage of different fuels (gasoline, diesel, electric, etc.)
  • Electric vehicles have lower/no tailpipe emissions
  • Changing fuel mix significantly affects emissions

Road Type Distribution

  • Percentage of travel on different road types
  • Urban vs. rural, restricted vs. unrestricted
  • Affects speed and emission rates

Common Scenarios

Scenario 1: Increase VMT

Question: "What if vehicle miles traveled increases by 15%?"

  1. Select your area and pollutant
  2. Find the VMT column in the table
  3. Multiply current VMT values by 1.15 (or add 15%)
  4. View results to see emissions increase

Scenario 2: Add Electric Vehicles

Question: "How do emissions change if 20% of vehicles are electric?"

  1. Select area and pollutant
  2. Increase % Electric to 20%
  3. Decrease % Gas (or other fuel) by 20% to maintain 100% total
  4. View results to see emissions decrease

Scenario 3: Change Vehicle Mix

Question: "What if we have more trucks and fewer cars?"

  1. Select area and pollutant
  2. Increase % Light Truck, % Heavy Truck
  3. Decrease % Car/Motorcycle
  4. View results to see how emissions change

Scenario 4: Modify Road Usage

Question: "What if more travel is on urban roads?"

  1. Select area and pollutant
  2. Increase % Urban Restricted, % Urban Unrestricted
  3. Decrease % Rural Restricted, % Rural Unrestricted
  4. View results to see impact

Tips for Using the Calculator

  1. Start with Defaults: Review default values before making changes
  2. Make Small Changes First: Test with small adjustments to understand the tool
  3. Maintain Totals: When adjusting percentages, ensure they add up to 100%
  4. Compare Scenarios: Use the comparison features to see differences clearly
  5. Document Your Changes: Note what you changed and why for your analysis

Understanding Results

Baseline vs. Adjusted

  • Baseline: Emissions using default MOVES values
  • Adjusted: Emissions using your edited values
  • Difference: Shows the impact of your changes

Percentage Changes

  • Positive %: Emissions increased
  • Negative %: Emissions decreased
  • Large %: Significant impact
  • Small %: Minor impact

Category Breakdowns

Results show emissions by:

  • Vehicle type (where changes occurred)
  • Fuel type (which fuels contribute most)
  • Road type (where travel happens)
  • Other categories depending on your selections

Troubleshooting

Table Not Editable

If you can't edit the table:

  1. Make sure you've selected a table (geographic area)
  2. Wait for data to load completely
  3. Try clicking directly on a cell
  4. Refresh the page if needed

Results Not Updating

If results don't change after editing:

  1. Make sure you pressed Enter or clicked elsewhere to save
  2. Wait a moment for calculations to complete
  3. Check that your edits are valid numbers
  4. Try refreshing the page

Values Don't Make Sense

If results seem incorrect:

  1. Verify your edits are reasonable (e.g., percentages add to 100%)
  2. Check that values are in correct units
  3. Review default values to understand expected ranges
  4. Try resetting and making smaller changes

Next Steps

After using the Calculator:

  1. Create an Order - Use your scenario to create a full modeling order
  2. Visualize Results - View your order data with interactive charts
  3. Generate a Report - Create a document with your analysis
  4. Compare Counties - Compare your area with others

Ready to create an order based on your scenario? See Creating Orders to submit a full modeling request.