Onroad Sources

Angelique Luedeker, ITEP

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Onroad Emissions

Emissions from vehiclesExhaustBrake and tire wearEvaporation

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Onroad Emissions (cont.)

2 main categoriesBy vehicle typeBy road type

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Onroad Emissions (cont.)

Vehicle types – GasolineLight duty gasoline vehicles (LDG Vs & Ts)

Passenger cars & trucksMotorcycles (MC)Heavy duty gasoline vehicles (HDGV 2b-

8b) Modifier based on gross vehicle weight rating

(gvwr) Trucks Busses

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Onroad Emissions (cont.) Vehicle types – Diesel

Light duty diesel vehicles (LDDV - cars)Light duty diesel trucks (LDDT < 8500 lb

gvwr)Heavy duty diesel trucks (HDDV 8500 to

>60K lb gvwr)School & public transportation busses

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Emission Factors (cont.)

Road types – rural & urban Arterials

Interstates Other major highways Minor highways

Collectors On & off ramps

Locals

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Emission Factors (cont.)

Emission Factors (EFs): MOVESEPA model – (complex black box)

Factors in emission modeling Climate (Seasonal temp, humidity, elevation)

Type of road (braking & accelerating estimates)

Registration records (how old are the cars)

Fuel type (sulfur content, vapor pressure, MTBE)

Other

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Emission Factors (cont.)

Emissions based on total vehicle miles traveled (VMT) per road type per year

** Emission estimates for paved and non-paved road dust also rely on VMT calculations!

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Emission Factors (cont.)

VMT exampleState Route 1 is a 10-mile-long stretch of

rural highwayOn average, 100 cars travel road every

dayTotal VMT = 10 miles x 100 vehicles/day x

365 days/year = 365,000 vehicle miles/year

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Emission Factors (cont.)

Emissions based on this estimate of VMT for cars on SR1Carbon monoxide (CO) EF for cars on rural

highways = 24.523 g/VMT (for this example)

Emissions estimate = 24.523 g/VMT x 365,000 VMT = 8,950,895 g of CO

8,950,895 g / 907184.74(g/ton) =

9.867 tons per year CO

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Emission Factors (cont.)

Emission FactorsAs detailed as you wantBased on vehicle type and road type

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Emission Factors (cont.)

Option 1 for tribesGet on-road mobile emission factors from state

agencies Difficult, many just use EPA estimates

Spend your time collecting good VMT

Use your VMT to do math with state emission factors to get reservation on road emissions

After math is done, enter into TEISS

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Emission Factors (cont.)

Option 2 for tribesVehicle population on tribal land different

than off tribal land E.g.: Average vehicle age?

Get training in MOVES and run it!Then use TEISS to import EFs

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Emission Factors (cont.)

With introduction of MOVES model, method for calculating on-road mobile emissions has changed

Contact ITEP when you’re ready to estimate on-road emissions. We’ll find assistance you need to get started