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1990
1996
Column C: Vehicle Miles Traveled (VMT) by Functional System, millions of miles Source: Federal Highway Administration, Office of Highway Information Management, Highway Statistics Summary To 1995 (Table VM-202, Vehicle-miles of travel, by functional system, 1980-1995; http://www.fhwa.dot.gov/ohim/summary95/section5.html) Columns D-J: Distribution of Vehicle Miles Traveled by Vehicle Type, % Source: Federal Highway Administration, Office of Highway Information Management, 1996 Highway Statistics (Table VM-4, Travel distribution by vehicle type, arterial system, and State, http://www.fhwa.dot.gov/ohim/1996/section5.html) Notes: Data for 1996 was used for both the 1996 and the 1990 calculation, since data for 1990 was not available from FHWA. As per Workbook instructions, the distributions for VMT in the categories Rural Major collector, Rural Minor collector, and Rural Local were assumed to be identical to the distribution for Rural Minor Arterial; and the distributions for Urban Collector and Urban Local were assumed to be identical to Urban Minor Arterial. Columns K-Q: Vehicle Miles Traveled by FHWA Vehicle Type, millions of miles Source: Calculation. Column C x Columns D-J, respectively. Columns R-X: Vehicle Miles Traveled by Inventory Vehicle Type, millions of miles Source: Calculation. Vehicle type conversion performed using Workbook Table 13.4-1. Notes: The Workbook provides emission factors for vehicles classified by a different set of types than those used in the FHWA data. Therefore vehicle miles traveled must be redistributed across this new set of types. The Workbook provides the following description of how the two sets of vehicle types relate to each other:
How the category of "Other 2-axle 4-tire vehicles" relates to the Inventory vehicle types is not clear; here it was included with "Passenger Cars" on the assumption that it refers to light trucks. Table 13.4-1 provides the fractional distribution of vehicle miles traveled by Inventory vehicle types. Using these two sets of information, the following formulas were used, where 'Fraction' refers to the values from Table 13.4-1: VMTLDGV = (VMTPassenger Cars + VMTOther 2-axle 4-tire vehicles) * FractionLDGV/(FractionLDGV + FractionLDDV) VMTLDGT = (VMTSingle-unit 2-axle 6-tire or more trucks) * FractionLDGT/(FractionLDGT + FractionHDGV + FractionLDDT) VMTHDGV = (VMTSingle-unit 2-axle 6-tire or more trucks) * FractionLDGT/(FractionHDGV + FractionHDGV + FractionLDDT) VMTLDDV = (VMTPassenger Cars + VMTOther 2-axle 4-tire vehicles) * FractionLDDV/(FractionLDGV + FractionLDDV) VMTLDDT = (VMTSingle-unit 2-axle 6-tire or more trucks) * FractionLDDT/(FractionHDGV + FractionHDGV + FractionLDDT) VMTLDDV = (VMTBuses + VMTSingle trailer + VMTMultiple trailer) VMTMC = VMTMotorcycles FractionLDGV = = 0.636 FractionLDGT = 0.26 FractionHDGV = 0.031 FractionLDDV = 0.004 FractionLDDT = 0.002 FractionHDDV = 0.059 FractionMC = 0.007 Column AA: Vehicle Miles Traveled by Inventory Vehicle Type, millions of miles Source: Summary of results from Columns R-X Columns AB-AC: Assumed Emissions Control Technology Source: Assumed. Notes: Data on the distribution of emission control technology for each vehicle type has not been obtained. Since the Workbook gives default emission factors for each vehicle type based on control technology, conservative assumptions were made about the actual technology in use. For each vehicle type, the technology with the largest emission factor was selected. Columns AD-AE: Emissions factors, g/km Source: Workbook Tables 13.4-6 and 13.4-7. Columns AF-AG: Emissions, million g Source: Calculation. Column AA x Columns AD and AE respectively, multiplied by 1.6 to convert emissions factors per kilometer to emissions factors per mile. Columns AH-AI: Emissions, metric tons of carbon equivalent Source: Calculation. Columns AG-AG x GWPs of N2O (310) and CH4 (21) respectively, multiplied by the ratio 12/44 to convert from metric tons of CO2 equivalent to metric tons of carbon equivalent. Column AJ: Total emissions, metric tons of carbon equivalent Source: Calculation. Column AH + Column AI.
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Greenhouse Gas Inventory for Rhode Island September 2000 Prepared by Brown University Center For Environmental Studies
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