Methodology Used to Develop MOVES Inputs

MOVES inputs were developed in accordance with guidance provided in EPA document 420b12028, 

titled “Using MOVES to prepare EIs for SIP and Conformity”. Discussions on these inputs are presented 

below.

Meteorology data used for this analysis was based on local information obtained from NOAA data at the 

Memphis International Airport (MIA) and was adapted for MOVES using the EPA conversion tool.

Temperature – The minimum and maximum daily temperature estimates of 73F and 97F, respectively, 

were derived from temperatures recorded over a three year period on the ten highest ozone exceedance 

days. These values have been relied upon in previous state implementation plans and were determined to 

be appropriate for use in the ozone season through the interagency consultation group (IAC) process.

Reid Vapor Pressure (RVP) – 7.8 pounds per square inch (psi) was used as 40 CFR 80.270, titled 

“Controls and Prohibitions on Gasoline Volatility”, indicates it is the ozone season regulatory maximum 

RVP for Shelby County, Tennessee. This value has been relied upon in previous state implementation 

plans and was determined to be appropriate for use in ozone season through the interagency consultation 

group (IAC) process.

Humidity – In a pre-analysis consensus IAC discussion and as recorded in a May 17, 2013 memorandum 

(the document is located in Attachment II – Intergovernmental Consultation) of the plan revision), TDEC 

provided three-year average data from the MIA for the month of July, including hourly temperatures and 

relative humidity (see the table below). The consensus assumed the meteorological MIA data could be 

applied throughout the entire modeled area of Shelby County. Later, it was requested by the Department 

that the MPO use meteorological data (to include absolute humidity) in the 2014-2017 TIP and 2040 

LRTP Conformity Demonstration, that had been used in the 2010 Shelby County Maintenance Plan for 

Ozone. However, the data introduced in the pre-analysis consensus was used to demonstrate conformity, 

which was acceptable, as the data was locally generated and therefore more representative than the 

MOVES default data.

Hourly Temperature and Relative Humidity Values

monthID hourID temperature relHumidity hourID temperature relHumidity

7 1 78.2 78.1 13 94.1 56.0

7 2 76.8 79.9 14 96.1 54.1

7 3 75.7 81.8 15 96.8 52.7

7 4 74.9 82.9 16 97.0 52.5

7 5 74.3 84.3 17 96.5 52.8

7 6 73.6 85.4 18 95.1 54.1

7 7 73.0 84.9 19 92.7 57.2

7 8 73.5 79.7 20 89.6 62.3

7 9 76.5 73.3 21 86.5 67.3

7 10 81.3 67.7 22 83.8 71.1

7 11 86.2 62.7 23 81.9 74.4

7 12 90.4 59.1 24 80.0 76.4
Source Type Population: MOVES default was used as a starting point for all source types. The MOVES 

Technical Guidance offers guidance on how to leverage default population and VMT data alongside local 

VMT data to arrive at an estimate of the local population. This guidance suggests comparing the ratio of 

default source type population to default VMT to the local VMT to arrive at an estimate of local source 

type population. This methodology was applied for all analysis years. A growth rate was not applied, 

since growth is inherently built in through this methodology.

Age Distribution: Used Shelby County, TN-specific data obtained from the UTK paper “Tennessee 

Traffic Data for Estimating Air Pollution Emissions in 2002” and an EPA converter to change 

MOBILE6-formatted information to MOVES format.

Vehicle Type VMT and VMT Fractions: This data importer asks the user for the VMT in the study area 

by HPMS vehicle class type, hourly VMT distributions, daily VMT distributions, and monthly VMT 

distributions. The HPMS vehicle class VMT is asked for on an annual basis. To determine this 

information, data was pulled from available travel demand models or from regional HPMS data.

HPMS Vehicle Class VMT – The HPMS vehicle class VMT was determined using the pre-processor 

developed within the travel demand model. The travel demand model classifies vehicles into automobiles, 

single unit trucks, and combination unit trucks. The three vehicle classes in the model were divided into 

the six HPMS vehicle class types through the pre-processor. Since the travel demand model produces 

daily weekday volumes, the EPA conversion tool was used to convert these daily VMT numbers to 

annual values.

Daily VMT Fraction – The University of Tennessee developed county-specific daily VMT fractions, 

which were applied in this analysis. This information was provided in a format appropriate for use in 

MOVES.

Monthly VMT Fraction – The University of Tennessee developed county-specific monthly VMT 

fractions, which were applied in this analysis. This information was provided in a format appropriate for 

use in MOVES.

Hourly VMT Fraction – The hourly VMT fraction was determined using the pre-processor developed 

within the travel demand model. To produce the information needed for the MOVES input file, the three 

vehicle classes in the model were expanded to the 13 MOVES vehicle source types. In addition, the four 

time of day periods in the model were expanded to represent each hour of the day. The default mix of offnetwork hourly distribution percentages was used for all vehicle classes.

The following table displays the Shelby County annual VMT produced by the MOVES VMT converter 

by source type and by year.
Shelby County Annual VMT by Source Type and by Year

Source Type

Source 

Type 

ID

Source Type VMT

2006 2021

Motorcycle 11 25,604,577 30,597,047

Passenger Car 21 6,116,293,396 7,308,869,710

Passenger Truck 31 1,393,265,928 1,664,929,980

Light Commercial Truck 32 465,466,353 556,224,433

Intercity Bus 41 3,712,127 4,873,218

Transit Bus 42 1,942,992 2,309,079

School Bus 43 25,201,662 32,497,370

Refuse Truck 51 2,897,462 2,074,341

Single Unit Shorthaul Truck 52 198,308,587 249,731,833

Single Unit Longhaul Truck 53 25,487,609 39,169,765

Motor Home 54 45,859,407 59,508,279

Combination Short-haul Truck 61 166,694,865 222,336,742

Combination Long-haul Truck 62 199,421,654 316,912,033

Total 8,670,156,620 10,490,033,832

Average Speed Distribution: The average speed distribution was determined using the pre-processor 

developed within the travel demand model. The vehicle classes in the model were expanded to the 13 

MOVES vehicle source types, and the hourly distribution was expanded from the four time periods in the 

model to each hour of the day.

Road Type Distribution: The road type distribution was determined using the pre-processor developed 

within the travel demand model. The vehicle classes in the model were expanded to the 13 MOVES 

vehicle source types

Ramp Fraction: The ramp fractions were determined using the pre-processor developed within the travel 

demand model.

Fuel Supply and Fuel Formulation: MOVES default data for Shelby County (obtained from the MOVES 

program) was used for analysis year 2006. The Tennessee Department of Environment and Conservation 

developed fuel supply and fuel formulation data for Shelby County for all analysis years 2012 and newer.

Fueltype and Technologies/Alternative Fuel Vehicle Types: If no information is entered for AVFT, 

MOVES assumes a default mix of alternative fuels. The MOVES default mix assumes a small percentage 

of compressed natural gas (CNG) transit buses. Since there are no CNG buses in the transit fleet for 

Shelby County, the default value for this file was modified to reflect only diesel and gasoline fuel types.

Inspection and Maintenance (I/M) Programs: The compliance factors in these files were adjusted to 

reflect not only participation within the City of Memphis, but also Shelby County as a whole. As stated in 

the EPA MOVES Technical guidance, this methodology can be used to avoid conducting two sets of runs 

that are then interpolated outside of MOVES.