Using MOVES in Project-Level

Carbon Monoxide Analyses 
EPA-420-B-10-041 

December 2010

Transportation and Regional Programs Division 

Office of Transportation and Air Quality 

U.S. Environmental Protection Agency

Using MOVES in Project-Level

Carbon Monoxide Analyses 
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Table of Contents

SECTION 1: INTRODUCTION................................................................................................................. 1

1.1 PURPOSE OF THIS GUIDANCE ............................................................................................................. 1

1.2 TYPES OF PROJECT-LEVEL CO ANALYSES .......................................................................................... 3

1.3 CONTACTS ........................................................................................................................................ 4

1.4 GUIDANCE AND EXISTING REQUIREMENTS ........................................................................................ 5

SECTION 2: ESTIMATING PROJECT-LEVEL CO EMISSIONS USING MOVES ......................... 6

2.1 CHARACTERIZING A PROJECT IN TERMS OF LINKS ............................................................................. 7

2.2 DETERMINING THE NUMBER OF MOVES RUNS...................................................................................12

2.3 DETERMINING BASIC RUN SPECIFICATION INPUTS ............................................................................14

2.4 ENTERING PROJECT DETAILS USING THE PROJECT DATA MANAGER..................................................20

2.5 GENERATING EMISSION RATES FOR USE IN AIR QUALITY MODELING ................................................29

SECTION 3: EXAMPLE: USING MOVES FOR A CO SCREENING ANALYSIS OF AN

INTERSECTION ........................................................................................................................................32

3.1 CHARACTERIZING THE PROJECT IN TERMS OF LINKS (SECTION 2.1)..................................................32

3.2 DETERMINING THE NUMBER OF MOVES RUNS (SECTION 2.2)............................................................33

3.3 DETERMINE BASIC RUN SPECIFICATION INPUTS (SECTION 2.3) .........................................................33

3.4 ENTERING PROJECT DETAILS USING PROJECT DATA MANAGER (SECTION 2.4) ..................................34

3.5 GENERATING EMISSION RATES FOR USE IN AIR QUALITY MODELING (SECTION 2.5) .........................40

SECTION 4: EXAMPLE: USING MOVES TO CALCULATE START AND IDLE EMISSION

FACTORS FOR A TRANSIT FACILITY................................................................................................41

4.1 CHARACTERIZING THE PROJECT IN TERMS OF LINKS (SECTION 2.1)..................................................41

4.2 DETERMINING THE NUMBER OF MOVES RUNS (SECTION 2.2)............................................................42

4.3 DETERMINE BASIC RUN SPECIFICATION INPUTS (SECTION 2.3) .........................................................42

4.4 ENTERING PROJECT DETAILS USING PROJECT DATA MANAGER (SECTION 2.4) ..................................43

4.5 GENERATING EMISSION RATES FOR USE IN AIR QUALITY MODELING (SECTION 2.5) .........................48

APPENDIX: CHARACTERIZING INTERSECTION PROJECTS FOR CO REFINED ANALYSES

USING MOVES...........................................................................................................................................49

A.1 INTRODUCTION ................................................................................................................................49

A.2 OPTION 1: USING AVERAGE SPEEDS..................................................................................................50

A.3 OPTION 2: USING LINK DRIVE SCHEDULES ........................................................................................51

A.4 OPTION 3: USING OP-MODE DISTRIBUTIONS......................................................................................53
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List of Figures

FIGURE 1. STEPS FOR USING MOVES IN PROJECT-LEVEL CO ANALYSES ............................................................ 6

FIGURE 2. DIAGRAM OF SUGGESTED LINKS FOR A SIMPLE INTERSECTION........................................................ 8

FIGURE 3. LINKS CHARACTERIZING THE PROPOSED INTERSECTION ................................................................33

FIGURE 4. METEOROLOGY INPUT (AVERAGE JANUARY CONDITIONS) – INTERSECTION...................................34

FIGURE 5. FLEET AGE DISTRIBUTION (PARTIAL) – INTERSECTION...................................................................35

FIGURE 6. FUEL SUPPLY TABLE – INTERSECTION ............................................................................................36

FIGURE 7. FUEL FORMULATION TABLE – INTERSECTION.................................................................................36

FIGURE 8. I/M PROGRAM DETAILS FOR PROJECT AREA ....................................................................................37

FIGURE 9. LINK SOURCE TYPE INPUT TABLE (PARTIAL) – INTERSECTION........................................................38

FIGURE 10. LINKS TABLE – INTERSECTION .....................................................................................................39

FIGURE 11. EMISSION RATE CALCULATIONS FOR EACH LINK – INTERSECTION................................................40

FIGURE 12. METEOROLOGY INPUT (AVERAGE JANUARY CONDITIONS) – TERMINAL.......................................43

FIGURE 13. FLEET AGE DISTRIBUTION – TERMINAL ........................................................................................44

FIGURE 14. FUEL SUPPLY TABLE – TERMINAL ................................................................................................45

FIGURE 15. FUEL FORMULATION TABLE – TERMINAL .....................................................................................45

FIGURE 16. LINK SOURCE TYPE INPUT TABLE – TERMINAL .............................................................................46

FIGURE 17. LINKS TABLE – TERMINAL............................................................................................................46

FIGURE 18. OFF-NETWORK TABLE..................................................................................................................47

FIGURE 19. OP-MODE DISTRIBUTION TABLE – TERMINAL ...............................................................................47

FIGURE 20. EMISSION RATE CALCULATIONS FOR EACH LINK – TERMINAL......................................................48
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Section 1: Introduction

1.1 PURPOSE OF THIS GUIDANCE

1.1.1 General

The purpose of this guidance is to describe how to use the MOVES emissions model to

estimate carbon monoxide (CO) emissions from transportation projects, including

roadway intersections, highways, transit projects, parking lots and intermodal terminals.1

This guidance can be applied when using MOVES to complete any project-level

quantitative CO analysis, including hot-spot analyses for transportation conformity

determinations, modeling project-level emissions for state implementation plan (SIP)

development, and completing analyses pursuant to the National Environmental Policy

Act (NEPA). This MOVES guidance applies in all states other than California, where the

most recently approved version of the EMFAC model is used. EPA has coordinated with

the Federal Highway Administration (FHWA) and Federal Transit Administration (FTA)

in developing this guidance.

MOVES is a computer model designed by EPA to estimate emissions from cars, trucks,

buses, and motorcycles.2 MOVES replaces the previous emissions model, MOBILE6.2,

based on an extensive review of in-use vehicle data. MOVES also incorporates a new

software framework and is designed to allow users to analyze motor vehicle emissions at

multiple scales, from national to county to project-level, using different levels of input

data. For project-level analyses, MOVES allows users to enter specific details of vehicle

activity for each link in the highway or transit project.

Note that this guidance covers only how to use MOVES in estimating CO project-level

emissions; there are other existing resources that support CO project-level analyses. For

example, EPA’s regulatory recommendations for CO air quality modeling can be found

in Appendix W to 40 CFR Part 51. Users should continue to consult the “1992 Guideline

for Modeling Carbon Monoxide from Roadway Intersections” (1992 Guideline) for

screening analyses of intersection projects for all issues not related to the calculation of

vehicle emission rates (including intersection scope and selection, receptor site selection,

and air quality modeling procedures).3 However, today’s MOVES guidance supersedes

the emission factor sections from the 1992 Guideline to reflect the use of MOVES for

project-level CO analyses. See Section 1.2.1 for further background on the 1992

Guideline. Finally, users should consult EPA’s “Transportation Conformity Guidance for

1 All references to MOVES in this guidance refer to MOVES2010a and future versions of the MOVES

model, unless otherwise noted at the time those versions are announced.

2 The latest MOVES model, User Guide, and supporting documentation are available online at:

www.epa.gov/otaq/models/moves/index.htm. The latest policy guidance on using MOVES for

transportation conformity and other purposes are also available at:

www.epa.gov/otaq/stateresources/transconf/policy.htm.

3

“1992 Guideline for Modeling Carbon Monoxide from Roadway Intersections,” (EPA-454/R-92-005,

November 1992); available online at: www.epa.gov/scram001/guidance/guide/coguide.pdf.
2

Quantitative Hot-spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance

Areas” for how to use MOVES to conduct quantitative PM hot-spot analyses.4

1.1.2 Using this guidance for transportation conformity hot-spot analyses

When using this guidance to complete quantitative CO hot-spot analyses for

transportation conformity purposes, certain specific requirements apply; these are

summarized here.

Transportation conformity is required under Clean Air Act section 176(c) (42 U.S.C.

7506(c)) to ensure that federally supported highway and transit project activities are

consistent with (“conform to”) the purpose of a SIP. EPA’s transportation conformity

rule (40 CFR 51.390 and Part 93) establishes the criteria and procedures for determining

whether transportation activities conform to the SIP in CO nonattainment and

maintenance areas. The list of areas currently designated nonattainment and maintenance

for CO can be found on EPA’s “Green Book” website at

www.epa.gov/oar/oaqps/greenbk/cindex.html. This guidance applies for transportation

conformity purposes in areas designated under the current CO NAAQS.5

Table 1 in 40 CFR 93.109(b) of the conformity rule outlines the requirements for projectlevel conformity determinations. For example, CO hot-spot analyses must be based on

the latest planning assumptions available at the time the analysis begins (40 CFR 93.110)

and the design concept and scope of the project must be consistent with that included in

the conforming transportation plan and transportation improvement program (TIP) or

regional emissions analysis (40 CFR 93.115). In addition, interagency consultation must

be used to develop a process to evaluate and choose models and associated methods and

assumptions to be used in CO hot-spot analyses (40 CFR 93.105(c)(1)(i)). The agencies

that may be involved in the interagency consultation process include the project sponsor,

state and local transportation and air quality agencies, EPA, and DOT. The roles and

responsibilities of various agencies for meeting the transportation conformity

requirements are addressed in 40 CFR 93.105 or in a state’s approved conformity SIP.

Refer to the conformity rule for a complete listing of all project-level conformity

requirements.

Finally, note that EPA is approving MOVES for use in CO hot-spot analyses for projectlevel conformity determinations, with a two-year grace period. The effective date of the

Federal Register notice constitutes the start of the conformity grace period.6 Refer to the

Federal Register notice for more information on EPA’s approval of MOVES for CO hot4

See “Transportation Conformity Guidance for Quantitative Hot-spot Analyses in PM2.5 and PM10

Nonattainment and Maintenance Areas,” (EPA-420-B-10-040, December 2010); available online at:

www.epa.gov/otaq/stateresources/transconf/policy.htm.

5 This guidance is applicable to current and future CO NAAQS revisions, unless EPA notes otherwise.

6 EPA posts all Federal Register notices for approving new emission models on its website:

www.epa.gov/otaq/stateresources/transconf/policy.htm#models.
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spot analyses. EPA has also issued additional policy guidance on when MOVES will be

required for hot-spot analyses and other purposes.7

1.2 TYPES OF PROJECT-LEVEL CO ANALYSES

It is important to understand the context for this MOVES guidance in the overall process

of completing project-level CO analyses. Project-level CO analyses consist of both

emissions and air quality modeling and can be completed using either a screening or a

refined analysis. Screening analyses estimate the maximum likely impacts of emissions

from a given source, generally at the receptor with the highest concentrations, based on

worst-case traffic and meteorological data. Such analyses can save effort in cases where

requirements are met. In contrast, refined analyses use detailed local information and

simulate detailed atmospheric processes to provide more specialized and accurate

estimates of how nearby sources affect air quality at downwind locations.

Unless otherwise noted, the guidance in this document can be used to estimate highway

and transit project emissions for all project-level CO analyses, both screening and

refined. The following sections further describe the relationship of this MOVES

guidance to particular types of screening and refined CO analyses.

1.2.1 Screening analyses of roadway intersections

The 1992 Guideline provides guidance on completing CO screening analyses of roadway

intersections and was based on EPA’s motor vehicle emissions model at the time,

MOBILE5. The MOBILE series of models has since been superseded as EPA’s official

model for estimating emissions from motor vehicles. As MOBILE5 is no longer an EPAapproved emissions model, this document therefore updates and supersedes the emission

factor guidance in the 1992 Guideline by describing how to use MOVES to develop

emission rates for CO screening analyses of intersections. With the release of this

document, any references to MOBILE5, MOBILE5 emission rates, or other emission

factor guidance in the 1992 Guideline should be disregarded.

Note that this document only supplants the 1992 Guideline insofar as to update the

emission rate calculation procedures to reflect the use of MOVES; the 1992 Guideline

otherwise remains in effect, and users should continue to consult that guidance for all

issues not related to the calculation of vehicle emission rates (including intersection scope

and selection, receptor site selection, and air quality modeling procedures).

7

“Policy Guidance on the Use of MOVES2010 for State Implementation Plan Development,

Transportation Conformity, and Other Purposes,” EPA-420-B-09-046 (December 2009); available online

at: www.epa.gov/otaq/stateresources/transconf/policy.htm#models.
4

1.2.2 All other screening analyses

This guidance also covers how to use MOVES for CO screening analyses of projects that

are not explicitly covered by the 1992 Guideline. This would include projects such as:

• A mainline highway segment not containing an intersection;

• An intersection project that includes off-network activity (that is, any activity not

occurring on a roadway, such as a truck stop, parking lot, or terminal facility);

• Any other project that includes off-network activity;

• Transit and other terminal projects.

The guidance will note when different procedures are appropriate when using MOVES to

complete a CO screening analysis for such projects. In some cases, the procedures for

using MOVES for these types of screening analyses will be the same as using MOVES

for a CO refined analysis (see Section 1.2.3). When this is the case, this guidance covers

these situations in a single section for brevity.

1.2.3 Refined analyses of any project

In certain situations, project sponsors may want or need to complete a CO refined

analysis. Although a refined analysis requires significantly more data and effort, this

option may be convenient for transportation projects that require both a PM and CO

quantitative hot-spot analysis. This guidance gives additional guidance on using MOVES

for refined analyses to explain how the full capabilities of the model can be employed in

these situations.

1.3 CONTACTS

For specific transportation conformity questions concerning a particular nonattainment or

maintenance area, please contact the transportation conformity staff person responsible

for your state at the appropriate EPA Regional Office. Contact information for EPA

Regional Offices can be found at:

www.epa.gov/otaq/stateresources/transconf/contacts.htm.

General questions on transportation conformity CO hot-spot analysis requirements can be

directed to David Bizot at EPA’s Office of Transportation and Air Quality,

bizot.david@epa.gov, (734) 214-4432.

Technical questions about this guidance can be directed to conformity-hotspot@epa.gov.
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1.4 GUIDANCE AND EXISTING REQUIREMENTS

This guidance does not create any new requirements. The Clean Air Act and the

regulations described in this document contain legally binding requirements. This

guidance is not a substitute for those provisions or regulations, nor is it a regulation in

itself. Thus, it does not impose legally binding requirements on EPA, DOT, states, or the

regulated community, and may not apply to a particular situation based upon the

circumstances. EPA retains the discretion to adopt approaches on a case-by-case basis

that may differ from this guidance but still comply with the statute and applicable

regulations. This guidance may be revised periodically without public notice.
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Section 2: Estimating Project-Level CO Emissions Using

MOVES

This guidance addresses the necessary steps to run MOVES to estimate a project’s

emissions for a project-level CO analysis. The guidance describes how to provide the

appropriate inputs to MOVES to generate the emission factors necessary to complete the

air quality analysis. This section presumes users already have a basic understanding of

how to run MOVES, either by attending MOVES training or reviewing the MOVES User

Guide.8Figure 1 describes the general process for estimating the CO emissions at the

project level using MOVES.

Figure 1. Steps for Using MOVES in Project-Level CO Analyses

8 Available via the MOVES website at: www.epa.gov/otaq/models/moves/
7

MOVES includes a default database of meteorology, fleet, activity, fuel, and control

program data for the entire United States. The data included in this database come from a

variety of sources and are not necessarily the most accurate or up-to-date information

available at the local level for a particular project. This guidance will describe when the

use of that default database is appropriate for a project-level CO analysis.

2.1 CHARACTERIZING A PROJECT IN TERMS OF LINKS

The first step in completing a project-level CO analysis using MOVES is to define a

project’s links in order to accurately capture emissions where they occur. Within

MOVES, a link represents a segment of road (or an “off-network” location as described

below) where a certain type of vehicle activity occurs. Generally, the links specified for

a project should include segments with similar traffic/activity conditions and

characteristics. For example, a free-flow highway segment with a relatively stable

average speed might be modeled as a single link, whereas an intersection will involve

several types of links, as described further below. From the link-specific activity and

other inputs, MOVES calculates emissions from every link of a project for a given time

period (or run). In MOVES, running emissions, including periods of idling at traffic

signals, are defined in the Links Importer (see Section 2.4.6).

This section gives different guidance on how to characterize links in MOVES, depending

on the type of project and CO analysis involved, as follows:

• For a screening analysis of a roadway intersection being completed in accordance

with the 1992 Guideline, see Section 2.1.1;

• For all other screening analyses, including intersection projects that include offnetwork activity, see Section 2.1.2;

• For a refined analysis of any project, see Section 2.1.2.

2.1.1 Screening analyses of roadway intersections

According to EPA’s regulatory recommendations for air quality modeling (Section 5.2.3

of Appendix W to 40 CFR Part 51), CO screening analyses of intersection projects

should use the CAL3QHC dispersion model. Performing such an analysis for an

intersection using the CAL3QHC dispersion model requires emission rates for both freeflow traffic (determined by defining “free flow” links) and idling traffic (determined from

“queue links”).9Free-flow links can be used to represent traffic approaching and

9 The 1992 Guideline describes how to use CAL3QHC when performing dispersion modeling for

intersections (see 1992 Guideline, page 1-5). To be consistent with the 1992 Guideline, this guidance

recommends use of the CAL3QHC queuing algorithm for intersection idle queues when completing a CO

screening analysis of an intersection. This differs from the recommendation for refined analyses, where

idling should be explicitly included in the link activity entered into MOVES, rather than determined by the

CAL3QHC queuing algorithm. Since the purpose of a screening analysis is inherently different from that

of a refined analysis, the separate methods still serve the respective goals of each approach.
8

departing an intersection. See Section 3 of this guidance for an example of how to use

MOVES for a CO screening analysis of an intersection.

Note that the 1992 Guideline does not cover screening analyses of intersections that

include off-network activity. For those situations, refer to Section 2.1.2.

Figure 2 is an example of a simple intersection showing free-flow approach, free-flow

departure, and queue links. The following sections provide more information on how to

define these links in MOVES.

Figure 2. Diagram of Suggested Links for a Simple Intersection

Free-flow Approach and Departure Links

Free-flow links are used to represent vehicle activity on intersection approach and

departure links. The intersection in Figure 2, for example, shows four free-flow approach

and four free-flow departure links. Free-flow links are described by the average speeds

experienced by drivers travelling along the link in the absence of the delay caused by an

intersection traffic signal. Users should define a free-flow link as the center-to-center

distance from the intersection of interest to the next intersection. As described in Section
9

4.7.4 of the 1992 Guideline, a maximum of 300 meters for this distance is sufficient, but

users may specify a longer distance for completeness.10

Queue Links

A queue link is used to represent vehicles idling at an intersection. The intersection in

Figure 2, for example, shows five queue links. Since MOVES is calculating a gram per

vehicle emission factor in this case, the exact length of the queue is not important.

2.1.2 All other screening analyses and refined analyses of any project

When completing screening analyses of projects not covered by the 1992 Guideline, or

any refined analysis, there are several options for characterizing link activity for projectlevel CO emissions. The following text describes how different types of links can be

characterized in MOVES.

General

In MOVES, activity on free-flow highway links can be defined by an average speed, link

drive schedule, or operating mode (“Op-Mode”) distribution (discussed in Section 2.4.8).

For analyses with MOVES, average speed and traffic volume is required, at a minimum,

for each link. If no other information is available, MOVES uses default assumptions of

vehicle activity patterns (called drive cycles) for average speed and type of roadway to

estimate emissions. Default drive cycles use different combinations of vehicle activity

(acceleration, deceleration, cruise, and/or idle) depending on the speed and road type.

For example, if the link average speed is 30 mph and it is an urban arterial (urban

unrestricted road type), MOVES uses a default drive cycle that includes a high proportion

of acceleration, deceleration, and idle activity as would be expected on an urban arterial

with frequent stops. If the average speed is 60 mph and it is a rural freeway (rural

restricted road type), MOVES uses a default drive cycle that assumes a higher proportion

of cruise activity, smaller proportions of acceleration and deceleration activity, and little

or no idle activity.

Project sponsors should determine average congested speeds by using appropriate

methods based on best practices used for highway analysis.11 Some resources are

available through FHWA’s Travel Model Improvement Program (TMIP).12

10 Since the goal of the MOVES run is to produce a grams/vehicle-mile emission rate, the exact length or

volume of each link is not important for running MOVES, although it is important for subsequent

CAL3QHC dispersion modeling.

11 When completing screening analyses of projects not covered by the 1992 Guideline, or any refined

analysis, idling vehicles should be represented in combination with decelerating, accelerating, and freeflow traffic on an approach segment of an intersection. Note that this is in contrast to the guidance given

when completing a CO screening analysis of an intersection, when the CAL3QHC queuing algorithm is

recommended in order to be consistent with the 1992 Guideline (see Section 2.1.1).

12 See FHWA’s Travel Model Improvement Program website: http://tmip.fhwa.dot.gov/.
10

Methodologies for computing intersection control delay are provided in the “Highway

Capacity Manual 2000.”13

As described further in Section 2.4.8, for refined analyses, users are encouraged to take

advantage of the full capabilities of MOVES for estimating emissions on different

highway and intersection project links when completing CO refined analyses. Although

average speeds and travel volumes are typically available for most transportation projects

and may need to be relied upon during the transition to using MOVES, users can develop

and use more precise data through the MOVES Operating Mode Distribution Importer or

Link Drive Schedule Importer, as described further below. When more detailed data are

available to describe the pattern of changes in vehicle activity (proportion of time in

acceleration, deceleration, cruise, or idle activity) over a length of road, MOVES is

capable of calculating these specific emission impacts. EPA encourages users to consider

these options for CO refined analyses of highway and intersection projects, especially as

MOVES is implemented further into the future, or for more advanced MOVES

applications.

Free-flow Highway Links

The links defined in MOVES should capture the expected physical layout of a project and

representative variations in vehicle activity. A simple example would be a single, one

directional, four-lane highway that could be characterized as just one link. More

sophisticated analyses may break up traffic flow on that single link into multiple links of

varying operating modes or drive cycles that may have different emission factors

depending on the relative acceleration, cruise, or deceleration activity on each segment of

that link. In general, the definition of a link will depend on how much the type of vehicle

activity (acceleration, deceleration, cruise or idle) changes over a length of roadway, the

level of detail of available data, and the modeling approach used with MOVES. For a

highway lane where vehicle behavior is fairly constant, the length of the link could be

longer and the use of detailed activity data will have a smaller impact on results.

Intersection Links

If the project analysis is a CO refined analysis involving intersections, the intersections

need to be treated separately from the free-flow links that connect to those intersections.

Although road segments between intersections may experience free-flow traffic

operations, the approaches and departures from the intersections will likely involve

acceleration, deceleration, and idling activity not present on the free-flow link. For

intersection modeling, the definition of link length will depend on the geometry of the

intersection, how that geometry affects vehicle activity, and the level of detail of

available activity information. Guidance for defining intersection links for a CO refined

analysis is given in the appendix, but the definition of links used for a particular project

13 Users should consult the most recent version of the Highway Capacity Manual. As of the release of this

guidance, the latest version is the “Highway Capacity Manual 2000,” which can be obtained from the

Transportation Research Board (see http://144.171.11.107/Main/Public/Blurbs/152169.aspx for details).
11

will depend of the specific details of that project and the amount of available activity

information.

Note: For both free-flow highway and intersection links, users may directly enter output

from traffic simulation models in the form of second-by-second individual vehicle

trajectories. These vehicle trajectories for each road segment can be input into MOVES

using the Link Drive Schedule Importer and defined as unique LinkIDs. There are no

limits in MOVES as to how many links can be defined; however, model run times

increase as the user defines more links. More information on using vehicle trajectories

from traffic microsimulation models for CO refined analyses can be found in the

appendix.

Off-Network Links

In any project-level CO analysis, the project being analyzed may include “off-network”

activity. Off-network in the context of MOVES refers to any activity not occurring on a

roadway. Examples of off-network activity include truck stops, parking lots, and transit

and other terminals. This section describes how to characterize off-network activity into

links; entering off-network links into MOVES using the Off-Network Importer will be

covered in Section 2.4.8.

For off-network sources such as a parking lot or transit terminal, the user should have

information on starts per hour (or peak hour starts) and number of vehicles idling during

each hour (or idling during peak hour). Additionally, if there are vehicles starting, it is

necessary to provide an estimate of the duration that vehicles are parked before starting

(soak-time distribution). It is recommended that the user divide such a project into

separate links to appropriately characterize variability in emission density within the

project area. In this case, each “link” describes an area with a certain number of vehicle

starts per hour, or a certain number of vehicles idling during each hour.

Some transit and other terminal projects may have significant running emissions similar

to free-flow highway projects (such as buses and trucks coming to and from an

intermodal terminal). These emissions can be calculated by defining one or more unique

running links as described in Section 2.1.2 and the appendix (that is, in addition to any

other roadway links associated with the project). These running link emissions can then

be aggregated with the emissions from starts and idling from non-running activity on the

transit or other terminal link outside of the MOVES model to generate the necessary air

quality model inputs.

When applicable, long duration idling (classified in MOVES as OpModeID 200) can

only be modeled in MOVES for long-haul combination trucks. Idling for other vehicles

and shorter periods of idling for long-haul combination trucks should be modeled as a

project link with an operating mode distribution that consists only of idle operation

(OpModeID 1). This can be specified in the Links table by inputting the vehicle

population and specifying an average speed of “0” mph.
12

Note: The user may choose to exclude sources such as a separate service drive, separate

small employee parking lot, or other minor sources that are determined to be

insignificant to project emissions.

2.2 DETERMINING THE NUMBER OF MOVES RUNS

The following section describes the number of MOVES runs that may be needed for

project-level CO analyses.14

2.2.1 Screening analyses of roadway intersections

For a CO screening analysis of an intersection project, only one MOVES scenario (run) is

necessary for each analysis year. To remain consistent with the 1992 Guideline for such

analyses, this guidance describes how to use “worst-case” conditions.15 To capture

anticipated worst-case conditions, users should define the MOVES run specification

(“RunSpec”) using the peak hourly traffic volume expected for the intersection project.

As stated in the 1992 Guideline, the peak hour traffic conditions are defined as the

average or typical values during the hour of the day which usually records the peak hour

traffic, rather than the worst case traffic conditions for the entire year.16 Average speeds,

vehicle mix, and idle times should reflect conditions at the peak period. Project sponsors

should use the appropriate methods based on best practices used for highway analysis in

the area for determining peak period traffic conditions. Some resources for determining

traffic characteristics are available through FHWA’s Travel Model Improvement

Program (TMIP).17 Guidance on how to enter these individual inputs into MOVES is

discussed in Section 2.4.

2.2.2 All other screening analyses

The 1992 Guideline does not expressly address what conditions should be captured for a

CO screening analysis of a project that is not solely a roadway intersection. Project

sponsors are encouraged to employ best professional practices and appropriate methods

and use the interagency consultation process or procedures to determine the appropriate

number of MOVES runs for these screening analysis situations.

2.2.3 Refined analyses of any project

If MOVES is being used to complete a CO refined analysis, more than one MOVES run

may be needed to capture any emission rate variation due to changes in temperature,

volume, speeds, and fleet mix over the course of the day, season, or year being analyzed.

14 If completing a CO quantitative hot-spot analysis for transportation conformity purposes, users should

refer to the conformity rule requirements when selecting travel activity data. See Section 1.1.2 for a

summary of these conformity requirements.

15 See 1992 Guideline, Section 4.

16 See 1992 Guideline, Section 1.3.

17 FHWA Travel Model Improvement Program website: http://tmip.fhwa.dot.gov/.
13

However, the specific number of MOVES runs needed will depend on the situation. For

example, where potential CO NAAQS violations are expected to occur in only one

quarter of the calendar year (e.g., only a wintertime violation), the user might choose to

model only a single day to represent all days within that quarter. However, if CO

NAAQS violations are expected in multiple quarters, or if variations in travel activity

and/or temperature within a single quarter need to be accounted for, then additional

MOVES runs may be necessary.

Project sponsors may have activity data collected at a range of possible temporal

resolutions. Depending on the sophistication of the activity data analysis for a given

project, these data may range from a daily average-hour and peak-hour value to hourly

estimates for all days of the year. The remainder of this section describes how project

sponsors can use MOVES for CO refined analyses in cases where they have (1) typical

travel activity data, and (2) more detailed travel activity data.

Projects with Typical Travel Activity Data

Traffic forecasts for highway and intersection projects are often completed for annual

average daily traffic volumes, with an allocation factor for a daily peak-hour volume.

This data can be used to conduct an analysis with MOVES that is representative for all

hours of the day, quarter, or year being considered. It is important to capture variation in

emission rates as activity and ambient temperature change over the period being

analyzed. For example, to account for these variations over the course of a day, the user

could run MOVES for four time periods: morning peak (AM), midday (MD), evening

peak (PM), and overnight (ON). The AM and PM peak periods could be run with peakhour traffic activity; MD and ON periods could be run with average-hour activity.

The results for each of the four hours can then be extrapolated to cover the entire day.

For example, the peak-hour volume can be used to represent activity conditions over a

three-hour morning (AM) and three-hour evening (PM) period. The remaining 18 hours

of the day can be represented by the average-hour volume. These 18 hours would be

divided into a midday (MD) and overnight (ON) period. The emission factors from this

day’s run could then be used represent the entire quarter being modeled.

The following is one suggested approach for an analysis employing the averagehour/peak-hour traffic scenario:

• Morning peak (AM) emissions based on traffic data and meteorology occurring

between 6 a.m. and 9 a.m.;

• Midday (MD) emissions based on data from 9 a.m. to 4 p.m.;

• Evening peak (PM) emissions based on data from 4 p.m. to 7 p.m.; and

• Overnight (ON) emissions based on data from 7 p.m. to 6 a.m.

Also, if there are local or project-specific data to suggest that the AM or PM peak traffic

periods will occur in different hours than the default values suggested here, or over a

longer or shorter period of time, the hours representing each time period may adjusted

accordingly.
14

Projects with Additional Travel Activity Data

Some project sponsors may have developed traffic or other activity data to show

variations in volume and speed across hours, days, or months. Additionally, if users are

modeling a transit or other terminal project, traffic volumes, starts, and idling estimates

are likely to be readily available for each hour of the day. Under either of these

circumstances, users may choose to apply the methodology described above (using

average-hour and peak-hour as representative for all hours of the time period being

calculated). Alternatively, additional MOVES runs could be generated to produce unique

emission factors using these additional activity data and emission factors for each period

of time for which specific activity data are available.

2.3 DETERMINING BASIC RUN SPECIFICATION INPUTS

Once the user has defined the project conceptually in terms of links and determined the

number of MOVES runs, the next step in using MOVES for project-level analyses is to

develop a run specification (“RunSpec”). The RunSpec is a computer file in XML

format that can be edited and executed directly or with the MOVES Graphical User

Interface (GUI). MOVES requires the user to set up a RunSpec to define the place and

time of the analysis as well as the vehicle types, road types, fuel types, and the emissionproducing processes and pollutants that will be included in the analysis. The headings in

this subsection describe each set of input options needed to create the RunSpec as defined

in the Navigation panel of the MOVES GUI. In order to create a project-level RunSpec,

the user must go down the Navigation panel filling in the appropriate data for each of the

items listed. Those panels are:

• Description

• Scale

• Time Spans

• Geographic Bounds

• Vehicles/Equipment

• Road Type

• Pollutants and Processes

• Manage Input Data Sets

• Strategies

• Output

• Advanced Performance Features

Additional information on each panel can be found in the MOVES User Guide available

on EPA’s website (www.epa.gov/otaq/models/moves/index.htm). The appropriate

sections of the user guide are referenced when describing the RunSpec creation process

below.
15

2.3.1 Description

(MOVES User Guide Section 2.2.1)

This panel allows the user to enter a description of the RunSpec using up to 5,000

characters of text. Entering a complete description of the RunSpec is important for users

to keep track of their MOVES runs as well as to provide supporting documentation for

the regulatory submission. Users may want to identify the project, the time period being

analyzed, and the purpose of the analysis in this field.

2.3.2 Scale

(MOVES User Guide Section 2.2.2)

The Scale panel in MOVES allows the user to select different scales or domains for the

MOVES analysis. All MOVES runs for project-level analyses must be done using the

“Project” domain in the “Scale” panel. The Project domain is necessary to allow

MOVES to accept detailed activity input at the link level.18

The Scale panel also requires users to select either “Inventory” or “Emission Rates”

which produces output as either grams/hour or grams/vehicle-mile emission rates,

respectively.

For screening analyses of intersections, since CAL3QHC requires emission rates in terms

of both grams/vehicle-mile for free-flow links and grams/hour for queue links, users

performing an analysis for a project which includes vehicle queuing (such as is the case

with an intersection) should select Inventory as output. From the Inventory output,

appropriate emission rates can be calculated through several post-processing steps

described in Section 2.5.

When completing screening analyses of projects not covered by the 1992 Guideline, or

any refined analysis, users may benefit from choosing either Rates or Inventory

depending on the specifics of the project (including the air quality model being used to

complete the analysis):

• When a grams/hour emission factor is needed for air quality modeling, users

should select “Inventory,” which produces results for total emissions on each link;

this is equivalent to a grams/hour/link emission factor.

• When a gram/vehicle-mile emission factor is needed, the “Emission Rates” option

should be selected to produce link specific grams/vehicle-mile emission factors.

This guidance explains the steps of post-processing both “Inventory” and “Emission

Rates” results to produce the desired emission factors in Section 2.5.

18 Running MOVES using the “County” or “National” domains would not allow for detailed link level

input or output that is needed for project-level CO analyses.
16

2.3.3 Time Spans

(MOVES User Guide Section 2.2.3)

The Time Spans panel is used to define the specific time period covered in the MOVES

run. The Time Spans panel is divided into five sections, which allow the user to select

time aggregation level, year, month, day, and hour included in the run.

The MOVES model processes one hour, of one day, of one month, of one year for each

run; that is, each MOVES run represents one specific hour. The user should enter the

desired time period in the MOVES Time Spans panel. Time aggregation should be set to

“hour,” which indicates no pre-aggregation. The “day” selection should be set to

“weekday” or “weekend,” but not both.

To be consistent with the 1992 Guideline, for a CO screening analysis of an intersection,

the year, month, and hour should be set to specifically describe the peak traffic scenario.

For example, the run describing a peak traffic scenario might be: 2015, January, 8:00 to

8:59 a.m. (both the start and end hours set to “8:00 a.m. to 8:59 a.m.”).

For CO refined analyses where multiple time periods are being modeled, the year, month,

and hour should be set to specifically describe each MOVES run. The user may also

choose to build a batch file to automate the process of running multiple scenarios.19

2.3.4 Geographic Bounds

(MOVES User Guide Section 2.2.4)

The Geographic Bounds panel allows the user to define the specific county that will be

modeled. The MOVES database includes county codes and descriptive information for

all 3,222 counties in the United States. Specifying a county in MOVES determines

certain default information for the analysis. Users should select the specific county

where the project is located. Only a single county (or single custom domain) can be

included in a MOVES run at the project level. If a project spans multiple counties, users

have three options:

1. If the county-specific local data is the same for all the counties in the project,

select the county in which the majority of the project is located;

2. If not, separate the project into multiple parts, each of which is in a separate

county, and do a separate MOVES run for each part; or

3. Use the custom domain option to model one unique area that represents all the

project counties.

19 For more information about using batch commands, see Appendix C of the MOVES User Guide, found

on EPA’s website at: www.epa.gov/oms/models/moves/index.htm.
17

2.3.5 Vehicles/Equipment

(MOVES User Guide Section 2.2.5)

The Vehicles/Equipment panel is used to specify the vehicle types that are included in the

MOVES run. MOVES allows the user to select from among 13 “source use types” (the

terminology that MOVES uses to describe vehicle types), and several different fuels.

Some fuel/source type combinations do not exist (e.g., diesel motorcycles) and therefore

are not included in the MOVES database. All project-level CO analyses should include

all vehicle types that are expected to operate in the project area. Users should select the

appropriate fuel and vehicle type combinations in the Vehicle/Equipment panel to reflect

the full range of vehicles that will operate in the project area. The fuel type “Placeholder

Fuel Type” should not be selected as it can cause errors.

2.3.6 Road Type

(MOVES User Guide Section 2.2.6)

The Road Type panel is used to define the types of roads that are included in the project.

MOVES defines five different Road Types:

• Rural Restricted Access – a rural highway that can be accessed only by an onramp;

• Rural Unrestricted Access – all other rural roads (arterials, connectors, and local

streets);

• Urban Restricted Access – an urban highway that can be accessed only by an onramp;

• Urban Unrestricted Access – all other urban roads (arterials, connectors, and local

streets); and

• Off-Network – any location where the predominant activity is vehicle starts and

idling (parking lots, truck stops, rest areas, freight or bus terminals).

MOVES uses these road types to determine the default drive cycle on a particular link.

For example, MOVES uses drive cycles for unrestricted access road types that assume

stop-and-go driving, including multiple accelerations, decelerations, and short periods of

idling. For restricted access road types, MOVES uses drive cycles that include a higher

fraction of cruise activity with much less time spent accelerating and idling.

Road Type is a necessary input into the RunSpec and users should select one or more of

the five road types that correspond to the road types of the project. The determination of

rural or urban road types should be based on the Highway Performance Monitoring

System (HPMS) functional classification of the road type.
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2.3.7 Pollutants and Processes

(MOVES User Guide Section 2.2.7)

The Pollutant and Processes panel is used to select both the types of pollutants and the

emission processes that produce them. When completing a CO screening analysis of an

intersection project using CAL3QHC, both free-flow and queue links will be

characterized. For CO emissions from these links, MOVES calculates emissions for two

separate processes:

• Running Exhaust

• Crankcase Running Exhaust

If modeling an intersection, users should select Carbon Monoxide (CO): “Running

Exhaust” and “Crankcase Running Exhaust.” Emission rates will be post-processed from

the MOVES output to calculate an aggregate of both processes.

MOVES does not automatically sum the appropriate processes to create an aggregate

emission factor, although EPA is considering creating one or more MOVES scripts that

would automate the summing of aggregate emissions when completing project-level

analyses.20 Therefore, the user should calculate aggregate CO for each link by using the

formula:

COaggregate total = (COrunning) + (COcrankcase running)

When completing screening analyses of projects not covered by the 1992 Guideline, or

any refined analysis, users should similarly sum the processes described above to

calculate aggregate emissions from the MOVES output.

If the project contains an off-network link, users should select Carbon Monoxide (CO):

“Starting Exhaust”, “Crankcase Starting Exhaust”, and/or “Extended Idling Exhaust”,

Crankcase Extended Idling Exhaust,” depending on the vehicle activity occurring on the

off-network link. Emission rates will need to be post-processed from the MOVES output

using the following equation to calculate an aggregate of all relevant processes:

CO off-network total = (COstarts) + (COcrankcase starts) + (COext. idle) + (COcrankcase ext. idle)

2.3.8 Manage Input Databases

(MOVES User Guide Section 2.2.8)

Most project-level CO analyses will not use the Manage Input Data Sets panel. One

possible application is to specify user-supplied databases to be read by the model during

execution of a run. However, for project-level analyses in MOVES, the Project Data

Manager, described in Section 2.4, serves this same function while providing for the

20 These scripts would be made available for download on the MOVES website

(www.epa.gov/otaq/models/moves/tools.htm), when available.
19

creation of data table templates and for the review of default data. EPA specifically

developed the Project Data Manager for project analyses and recommends using it to

create and specify user supplied database tables instead of the Manage Input Databases

panel.

2.3.9 Strategies

(MOVES User Guide Section 2.2.9)

In MOVES, the Strategies panel allows the user to model alternative control strategies

that affect the composition of the vehicle fleet. The MOVES model has two alternative

control strategies built into the Strategies panel:

• The Alternative Vehicle Fuels and Technologies (AVFT) strategy allows users to

modify the fraction of alternative fueled vehicles in each model year.

• The On-Road Retrofit strategy allows the user to enter information about diesel

trucks and buses that have been retrofitted with emission control equipment.

A common use of the AVFT panel would be to change the diesel fractions of the fleet.

Users can modify the default assumptions about diesel, gasoline, and CNG use for each

source type and model year. If local information is available on these fractions, the

AVFT should be used to modify the defaults. For instance, users modeling a transit

facility may use the AVFT to specify that the entire fleet of buses uses CNG, or entirely

diesel, rather than a default mix of both fuel types.

Another application of the Strategies panel would be to apply a retrofit program to the

fleet. For example, a bus terminal project might include plans to mitigate emissions by

retrofitting the bus fleet that will operate at that terminal with control equipment that

reduces CO emissions. In that case, the user would specify the details of the retrofit

project using the On-Road Retrofit strategy panel. The latest guidance on retrofit

programs can be located at the EPA’s conformity website:

www.epa.gov/otaq/stateresources/transconf/policy.htm. Strategies that affect vehicle

activity, such as implementing a truck idle reduction plan, should be handled in the OffNetwork Importer and Links Importer.

2.3.10 Output

(MOVES User Guide Section 2.2.10)

Selecting Output in the Navigation panel provides access to two additional panels:

General Output and Output Emissions Detail. Each of these allows the user to specify

aspects of the output data.

Under General Output, users should make sure to choose “grams” and “miles” for the

output units in order to provide results for air quality modeling. Also, “Distance

Traveled” and “Population” should be selected under the “Activity” heading to obtain

vehicle volume information for each link in the output.
20

Output Emissions Detail is used to specify the level of detail desired in the output data.

Emissions by hour and link are the default selections and cannot be changed. EPA

recommends that users select the box labeled “Emission Process.” No other boxes should

be selected in order to produce fleet aggregate emission rates for each link. Emission

rates for each process can be appropriately summed to calculate aggregate CO emission

rates for each link (as described previously in Section 2.3.7).

2.3.11 Advanced Performance Features

(MOVES User Guide Section 2.2.11)

Most project-level CO analyses will not use the Advanced Performance Features panel.

This menu item is used to invoke features of MOVES that improve run time for complex

model runs by saving and reusing intermediate results. For specific applications, the user

may want to “save data” for deriving the intermediate MOVES calculation of an OpMode Distribution from an average speed. This is discussed further in the MOVES User

Guide.

2.4 ENTERING PROJECT DETAILS USING THE PROJECT DATA MANAGER

After completion of all the necessary panels to create the RunSpec, the user must then

create the necessary input database tables that describe the project in detail. For a typical

project-level analysis, only one set of input database tables will need to be created. This

is done using the Project Data Manager, which can be accessed from the Pre-Processing

menu item at the top of the MOVES GUI or by selecting Enter/Edit Data in the Domain

Input Database section of the Geographic Bounds Panel.

The Project Data Manager includes multiple tabs that open importers, which are used to

enter project-specific data. These tabs and importers are:

• Meteorology

• Age Distribution

• Fuel Supply

• Fuel Formulation

• Inspection and Maintenance

• Link Source Type

• Links

• Link Drive Schedule

• Operating Mode Distribution

• Off-Network

Each of the importers allows the user to create a template file with required data field

names and with some key fields populated. The user then edits this template to add

project specific local data with a spreadsheet application or other tool and imports the

data files into MOVES. In some importers, there is also the option to export default data

from the MOVES database in order to review it. Once the user determines that the
21

default data are accurate and applicable to the particular project, or determines that the

default data need to be changed and makes those changes, the user then imports that data

into MOVES. Details of the mechanics of using the data importers are provided in the

MOVES User Guide. Guidance for the use of these importers when completing projectlevel CO analyses is described below.

Note that for a typical CO screening analysis of an intersection without any off-network

links, not all of the importers will be used. For instance, users may choose not to import

a Link Drive Schedule, Operating Mode Distribution, or Off-Network table for a

screening analysis where all activity is defined through the average speed function of the

Links input.

For all project-level CO analyses, if the project contains an off-network link, both the

Off-Network table and Operating Mode Distribution table should be populated and

imported. See Sections 2.1.2 and 2.4.8 for information on modeling off-network links in

MOVES.

2.4.1 Meteorology

(MOVES User Guide Section 2.3.3.4.1)

The Meteorology Data Importer is used to import temperature and humidity data for the

month and hour that are defined in the MOVES run specification. Default temperature

and humidity values are available in MOVES, but are not recommended for use in a

project-level CO analysis.

Screening Analyses of Roadway Intersections

The 1992 Guideline recommends the following two options for defining temperature and

humidity for screening analyses of intersections:

1. The temperature and humidity corresponding to each of the ten highest nonoverlapping 8-hour CO monitoring values for the last three years should be

obtained. The average 8-hour temperature and humidity for each event should be

calculated and then all ten values should be averaged for use with MOVES.

2. Alternatively, the average temperature and humidity in January may be used.21

Meteorological data may be obtained either from the National Weather Service (NWS) or

as part of a site-specific measurement program. Local universities, the Federal Aviation

Administration (FAA), military stations, and state and local air agencies may also be

sources of such data. The National Oceanic and Atmospheric Administration’s National

Climatic Data Center (NCDC; online at www.ncdc.noaa.gov) is the world’s largest active

archive of weather data through which years of archived data can be obtained. A data

source should be selected that is representative of local meteorological conditions.

21 See 1992 Guideline, Section 4.7.1.
22

All Other Screening Analyses

The 1992 Guideline does not expressly address what conditions should be captured for a

CO screening analysis of a project that is not solely a roadway intersection. However,

the guidance given in the 1992 Guideline may also be appropriate for any CO screening

analysis.

Refined Analyses of Any Project

For refined analyses, users should enter data specific to the project’s location and time

period modeled, as CO emissions are found to vary significantly depending on

temperature. As discussed in Section 2.2.3, MOVES will typically be run for multiple

time periods and specific meteorology data that accurately represents these runs is

needed. Within each period of day in each quarter selected, temperatures should be used

that represent the average temperature within that time period. For example, for January

AM peak periods corresponding to 6 a.m. to 9 a.m., the average January temperature

based on the meteorological record for those hours should be used in estimating the

average January AM peak period temperature for MOVES runs. The user may choose to

run additional hours and temperatures beyond the number of traffic periods for which

data exist. For example, within an 11-hour overnight (ON) modeling period, temperature

data could be used to differentiate hours with significantly different temperatures, despite

having assumed identical traffic estimates. Humidity estimates should be based on the

same hours and data source as the temperature estimates.

2.4.2 Age Distribution

(MOVES User Guide Section 2.3.3.4.3)

The Age Distribution Importer is used to enter data that provides the distribution of

vehicle fractions by age for each calendar year (yearID) and vehicle type

(sourceTypeID). These data are required for running MOVES at the project level. The

distribution of ageID (the variable for age) fractions must sum to one for each vehicle

type and year.

To build a MOVES-compatible age distribution table for project-level CO analyses, there

are three possible options.

1. If available, users should use the latest available state or local age distribution

assumptions from their SIP or transportation conformity regional emissions

analysis. For the initial transition from MOBILE6.2 to MOVES, EPA has

provided a registration distribution converter.22 The tool allows users to input a

MOBILE6.2 registration distribution table (10, 10, 5 format) and obtain a

MOVES age distribution table. Over time, users should develop age distribution

data consistent with the requirements of MOVES.

22 This convertor can be found online at: www.epa.gov/otaq/models/moves/tools.htm.
23

Some users may have local registration distribution tables for all vehicle classes.

However, there may be cases where the user has registration distributions only for

one or more vehicle classes (e.g., light duty vehicles) and therefore relies on

MOBILE6.2 defaults for the remaining vehicle classes. In these cases, the user

may use MOVES default distributions available on the EPA’s website.

2. If the project is designed to serve a fleet that operates only locally, such as a

drayage yard or bus terminal, the user should provide project-specific fleet age

distribution data. For most captive fleets, an exact age distribution should be

readily available or obtainable. The data should be in a format compatible with

MOVES. This format includes age fractions as a distribution of 30 model-years

rather than the 25 used in MOBILE6.2. Additionally, vehicle categories need to

be in terms of the 13 MOVES source types.

3. If no state or local age distribution is available, the MOVES default age

distribution should be used. This can be obtained from the tables available on the

EPA website: www.epa.gov/otaq/models/moves/tools.htm. The user can select

the analysis year(s) and find the corresponding age distribution. These fractions

are national defaults and could be significantly different than the local project age

distribution. Age distribution can have a considerable impact on emission

estimates, so the default data should be used only if an alternative state or local

dataset cannot be obtained.

2.4.3 Fuel Supply and Formulation

(MOVES User Guide Section 2.3.3.4.8 and 2.3.3.4.9)

The user must define in MOVES what fuel(s) and fuel mix will be used in the project

area. The Fuel Supply Importer and Fuel Formulation Importer are used to enter the

necessary information describing fuel type and fuel mix for each respective MOVES run.

Users should review the default fuel formulation and fuel supply data in MOVES and

make changes only if local volumetric fuel property information is available. Otherwise,

EPA recommends that the MOVES default fuel supply and formulation information be

used for project-level CO analyses. The lone exception to this is in the case of Reid

Vapor Pressure (RVP), where a user should change the value to reflect the differences

between ethanol and non-ethanol blended gasoline.

For additional guidance on defining fuel supply and formulation information, consult the

EPA document “Technical Guidance on the Use of MOVES2010 for Emission Inventory

Preparation in State Implementation Plans and Transportation Conformity” available

online at: www.epa.gov/otaq/stateresources/transconf/policy.htm.
24

2.4.4 Inspection and Maintenance (I/M)

(MOVES User Guide Section 2.3.3.4.10)

Projects within areas covered by an I/M program should define the program in the

MOVES Inspection and Maintenance Importer. Users should first examine the default

I/M program description included in MOVES for the particular county in question. The

default I/M data can be reviewed by selecting the Export Default Data button in the I/M

tab of the Project Data Manager. Users should review the details of the default I/M

program and make any necessary changes to match the actual local program that is

planned to be in place in the year being analyzed.

For additional guidance on defining an I/M program in MOVES, consult the EPA

document “Technical Guidance on the Use of MOVES2010 for Emission Inventory

Preparation in State Implementation Plans and Transportation Conformity” available

online at: www.epa.gov/otaq/stateresources/transconf/policy.htm.

2.4.5 Link Source Type

(MOVES User Guide Section 2.3.3.4.13)

The Link Source Type Importer allows users to enter the fraction of the link traffic

volume which is represented by each vehicle type (source type). It is not required if the

project contains only an off-network link. For each LinkID, the

“SourceTypeHourFractions” must sum to one across all source types.

Additionally, the user must ensure that the source types selected in the MOVES

Vehicles/Equipment panel match the source types defined through the Link Source Type

Importer.

There are no defaults that can be exported from the Link Source Type Importer. For any

analysis at the project level, the user must provide source type fractions for all vehicles

being modeled. There are two options available to populate the Link Source Type input:

1. For projects that will have an entirely different source type distribution than that

of the regional fleet, the preferred option is for the user to collect project-specific

data. This data could be based on analysis of similar existing projects.

2. If the project traffic data suggests that the source type distribution for the project

can be represented by the distribution of the regional fleet for a given road type,

the user can provide a source type distribution consistent with the road type used

in the latest regional emissions analysis.
25

2.4.6 Links

(MOVES User Guide Section 2.3.3.4.12)

The Links Importer is used to define the individual roadway links. All links being

modeled should have unique IDs. The Links Importer requires information on each

link’s length (in miles), traffic volume (units of vehicles per hour), average speed (miles

per hour), and road grade (percent). Users should follow guidance given in Section 2.1

when determining the number of links and the length of each link.

2.4.7 Describing vehicle activity for screening analyses of roadway intersections

The Links Importer is also where users may describe vehicle activity for intersection

links, including the approach/departure free-flow links and queue links.

Consistent with the 1992 Guideline, to produce emission rates for a CO screening

analysis of an intersection, users performing such an analysis should calculate emissions

based on average speeds. The average speed defined for each link is internally matched

with a MOVES default drive cycle based on that average speed, road grade, and road

type and used to calculate emissions. The intersection free-flow links and queue links

should be defined as follows:

Free-Flow Approach and Departure Links

An average free-flow speed and traffic volume should be defined for each free-flow link

that reflects conditions at peak traffic conditions. A variety of methods are available to

estimate average free-flow speed. Project sponsors should use the appropriate method

based on best practices used for highway analysis in the area for determining congested

average speeds.

Queue Links

Queue links should be assigned an average speed of zero, indicating entirely idle

operation.

2.4.8 Describing vehicle activity for all other screening analyses and refined analyses

of any project

When completing screening analyses of projects not covered by the 1992 Guideline, or

any refined analysis, users may use the average speed input or choose to use alternative

MOVES activity inputs such as a Link Drive Schedule or Operating Mode Distribution.

This section describes these options in more detail, as well as describing how to enter offnetwork activity into MOVES.
26

Entering Link Activity into MOVES

MOVES determines vehicle emissions based on operating modes, which represent

different types of vehicle activity such as acceleration (at different rates), deceleration,

idle, and cruise that have distinct emission rates. MOVES handles these data in the form

of a distribution of the time vehicles spend in different operating modes. This capability

is central to the use of MOVES for CO refined analyses, in particular, because it allows

for the analysis of fine distinctions between vehicle behavior and emissions. For

example, the full emission benefits of a project designed to smooth traffic flow can best

be realized by taking into account the changes in acceleration, deceleration, and idle

activity that result from the project.

There are several methods that users may employ to calculate an Op-Mode distribution

based on the project design and available traffic information. MOVES currently offers

three options that the user can employ to add link activity data, depending on data

availability. These are:

1. Provide average speed and road type through the Links input:

Using this approach, MOVES will calculate emissions based on a default drive

cycle for a given speed, grade, and road type. Input of link drive schedules or

operating mode distributions is not needed. For users modeling a free-flow link

with only basic information on average speed and volume on a link, this option

may be appropriate. This approach accounts for some differences in emissions

due to changes in operating modes associated with different average speeds on a

specific road type. However, this approach provides the least resolution when

analyzing the emission impact of a project because the default drive cycles used

by the model may not accurately reflect the specific project. For instance, due to

the range of operating modes associated with intersection projects, a single

average speed would not spatially capture localized idling and acceleration

emissions.

2. Provide a link drive schedule using the Link Drive Schedule Importer:

The Link Drive Schedule Importer allows the user to define the precise speed and

grade as a function of time (seconds) on a particular roadway link. The time

domain is entered in units of seconds, the speed variable is miles-per-hour and the

grade variable in percent grade (vertical distance/lateral distance, 100% grade

equals a 45-degree slope). MOVES builds an Operating Mode Distribution from

the Link Drive Schedule and uses it to calculate link running emissions.

Individual Link Drive Schedules cannot be entered for separate source types. The

Link Drive Schedule therefore represents the “tracer” path of an average vehicle

on each link. Link drive schedules could be based on observations using methods

such as chase (floating) cars on similar types of links, or on expected vehicle

activity based an analysis of link geometry. Link drive schedules will only

represent average vehicle activity, not the full range of activity that will occur on

the link. As described in the appendix, users can overcome this limitation by
27

defining multiple links for the same portion of the project (links that “overlap”)

with separate source distributions and drive schedules to model individual

vehicles.

3. Provide a detailed operating mode distribution for the link:

The Operating Mode Distribution Importer allows the user to directly import

operating mode fraction data for source types, hour/day combinations, roadway

links, and pollutant/process combinations that are included in the run

specification. Operating mode distributions may be obtained from:

• Op-Mode distribution data from other locations with similar geometric

and operational (traffic) characteristics;23 or

• Output from traffic micro-simulation models.24

Users should consider the discussion in this section when deciding on the appropriate

activity input, as the MOVES model is capable of using complex and highly resolved

activity datasets to calculate link level emissions. EPA encourages the development of

validated methods for collecting verifiable vehicle Op-Mode distribution data at locations

and in traffic conditions representative of different projects covered by this guidance.

However, the user should determine the most robust activity dataset that can be

reasonably collected while still achieving the goal of determining an accurate assessment

of the CO air quality impacts from a given project. The decision to populate the Links

table, Link Drive Schedule, or Op-Mode Distribution should be based on the data

available to the user and should reflect the vehicle activity and behavior on each link.

Note: If either the average speed or link-drive schedule approach is used, it is not

necessary to input an Op-Mode distribution for on-road link activity.

Entering Off-Network Links

Using the Off-Network Importer is only necessary for project-level CO analyses if the

project includes an area where vehicles are parked, starting their engines, or in extended

idling mode (such as a truck stop, parking lot, or passenger or freight intermodal

terminal). In these cases, the off-network table should be populated and imported.25

23 For example, chase (or floating) cars, traffic cameras, and radar guns have been used previously to

collect some traffic data for use in intelligent transportation systems and other applications. EPA

encourages the development of validated methods for collecting verifiable vehicle operating mode

distribution data at specific locations representative of different projects covered by this guidance.

24 A traffic micro-simulation model can be used to construct link drive schedules or operating mode

distributions if prior validation of the model’s predictions of speed and acceleration patterns for roadway

links similar to those in the project was conducted. If a user has a micro-simulation model that has been

previously demonstrated to adequately predict speed/acceleration patterns for relevant vehicle classes (e.g.,

heavy-duty), and has a procedure for importing data into MOVES, it may be appropriate to use the microsimulation model.

25 See Section 2.3.3.4.16 of the MOVES User Guide for more information about using the Off-Network

Importer.
28

There are no default values available for any of the off-network inputs, so users will need

to populate the Off-Network table with information describing vehicle activity in the offnetwork area being modeled. The required fields are vehicle population, start fraction,

and extended idle fraction:

• The vehicle population reflects the total number of vehicles parked, starting, or

idling on the off-network area over the course of the hour covered by the MOVES

run.

• The start fraction is the fraction of the total vehicle population that starts during

the hour.

• The extended idle fraction specifies the fraction of time that the vehicle

population spends in extended idle operation in the hour.26

Extended idle operation applies only to long-haul combination trucks and is defined as

the operation of the truck's propulsion engine when not engaged in gear for a period

greater than 15 consecutive minutes, except when associated with routine stoppages due

to traffic movement or congestion.27 Shorter periods of idling for long-haul combination

trucks and all idling for other vehicles should be modeled as a project link with an OpMode distribution that consists only of idle operation (Op-Mode 1). This can be

specified in the Links table by inputting the vehicle population and specifying an average

speed of “0” mph.

For vehicle population inputs, the user should be able to rely on existing project

documentation. The user will also need to estimate the number of starts and idle

operation of the facility during the peak hour. For example, in a bus terminal project, the

user could estimate the number of starts and idling for the peak hour based on expected

passenger ridership and proposed operating schedules for the buses using the terminal.

Information on start and idle activity should be specific to the project being modeled.

However, data from similar projects could be adapted for use in a CO hot-spot analysis,

when appropriate. For instance, the ratio of starts to vehicles for a project being analyzed

could be determined by studying a similar parking lot.

If an off-network link is defined, users must also define an Op-Mode distribution that

describes the soak-time distribution of vehicles on the link; this will affect the start

emissions. Additionally, any extended idle operation on an off-network link must be

described by the Op-Mode distribution with a fraction of 1.0 for Op-Mode 200 (Extended

Idle Mode). Since there is only one possible extended idle mode in MOVES, this

fraction should always be 1.0.

There are no default soak-time distributions available. Soak times and soak-time

distributions should be specific to the type of project being modeled. The soak time is

the time a vehicle is stationary with the engine turned off, following the last time it was

26 Parked fraction is not required as an input and can be left blank.

27 See “Guidance for Quantifying and Using Long Duration Truck Idling Emission Reductions in State

Implementation Plans and Transportation Conformity; available online at

www.epa.gov/smartway/documents/420b04001.pdf.
29

operated. This information could either be directly collected or obtained from

information collected for a similar project. For instance, a park-and-ride lot may have

vehicles parked for eight or nine hours prior to starting, while an intermodal freight

terminal may have vehicles parked for only one hour before starting. This information

should be defined through the appropriate distribution of soak-time Op-Modes

(OpModeIDs 101-108) in the Op-Mode distribution table.

The methods and assumptions used to derive off-network inputs (including starts, idle

activity, and soak-time distributions) should be documented as part of the analysis,

including any adjustments based on data from similar projects.

2.5 GENERATING EMISSION RATES FOR USE IN AIR QUALITY MODELING

When run to calculate “Inventory” output (as described in Section 2.3.2), the MOVES

model does not explicitly produce the required emission rates. The emission results are

calculated by MOVES in terms of absolute grams for each link defined in the “Links”

input file. Therefore, the user will need to perform several simple calculations to derive a

grams/vehicle-mile or grams/vehicle-hour emission rate. The following sections describe

these procedures in more detail for CO screening analyses of intersections as well as

other situations.

2.5.1 Screening analyses of roadway intersections

As noted earlier, according to EPA’s regulatory recommendations for air quality

modeling (Section 5.2.3 of Appendix W to 40 CFR Part 51), the CAL3QHC model

would be used for CO screening analyses of intersection projects. CAL3QHC calculates

air quality estimates based on the defined emission rate, volume of traffic on, and length

of a given link in combination with information on signal timing, queue length, and

Level-of-Service (LOS). For these analyses, the required information from MOVES is a

grams/vehicle-mile emission rate for each free-flow link and a grams/vehicle-hour

emission rate for each queue link, as described below:

Free-flow Approach and Departure Links

For links characterized as “free-flow” segments of a project, a gram/vehicle-mile

emission rate is needed for CAL3QHC.

All of the information necessary to generate a grams/vehicle-mile emission rate is

available in the MOVES MySQL output database. After running MOVES for a

particular hour/day/month scenario, emission results can be located in the user defined

MOVES output database in the table “movesoutput.” All links defined through the

Project Data Manager will have results in the column “emissionQuant.” The units should

be in grams (as defined in the MOVES RunSpec; see Section 2.3.10).
30

As shown in the equation in Section 2.3.7, all relevant processes should be summed

together to get a single emissionQuant value. This value should then be divided by the

“distance traveled” value reported as “activityTypeId 1” in the “movesactivityoutput”

table to get grams/vehicle-mile.

A brief example: for a two mile free-flow approach link with a volume of 100

vehicles/hour, MOVES estimates emissions at 500 grams and reports a distance traveled

value of 200 miles (reflecting 100 vehicles covering a distance of two miles). Following

the simple calculation below, the resulting emission rate would be 2.5 grams/vehicle-mile

for that link:

500 grams / 200 vehicle miles traveled = 2.5 grams/vehicle-mile

This calculation should be completed for each free-flow approach and departure link

defined in the project.

Queue Links

For links characterized as “queue” segments of a project, a gram/vehicle-hour emission

rate is needed for CAL3QHC.

As discussed above, all links defined through Project Data Manager will have results in

the column “emissionQuant.” The units should be in grams (as defined in the MOVES

RunSpec; see Section 2.3.10). As shown in the equation in Section 2.3.7, all relevant

processes should be summed together to get a single emissionQuant value. This value

should then be divided by the hourly traffic volume of the link to get a grams/vehiclehour rate. The hourly traffic volume should be obtained from the output database table

“movesactivityoutput” (values reported for “activityTypeId 6”). This calculation should

be completed for each queue link defined in the project.

2.5.2 All other screening analyses and refined analyses of any project

When completing screening analyses of projects not covered by the 1992 Guideline, or

any refined analysis, MOVES provides results as either an emission total (if “Inventory”

output is selected when developing the RunSpec) or an emission factor (if “Emission

Rates” output is selected). The emission results are produced for each pollutant and

process and are calculated in terms of grams per link or grams/vehicle-mile per link.

Using the equations given in Section 2.3.7, the user will need to sum the appropriate

pollutants and processes to derive a link total grams/vehicle-mile or grams/vehicle-hour

emission factor. These totals will be needed as inputs into the appropriate air quality

model.

Emission results from each MOVES run can be found in the MOVES output database, as

described below:
31

• Grams/vehicle-mile. All of the information needed to generate the necessary

inputs is available in the MOVES MySQL output database. If “Rates” is selected

in the Scale panel, MOVES will produce output in terms of grams/vehicle-mile

for each link. After running MOVES for a particular hour/day/month scenario,

emission results can be located in the user defined MOVES output database in the

table “rateperdistance.” All links defined in the Project Level Importer will have

results in the column “rateperdistance.” The units should have been defined as

grams and miles in the MOVES RunSpec. As shown in the equations in Section

2.3.7, all relevant pollutants and processes should be summed together to get a

single “rateperdistance” value.

• Grams/vehicle-hour. All of the information needed to generate the necessary

inputs is available in the MOVES MySQL output database. If “Inventory” is

selected in the Scale panel, MOVES will produce output in terms of

grams/hour/link. The user should then calculate aggregate CO grams/hour

emission factors by summing the appropriate pollutants and processes as

described in Section 2.3.7.

Note: If MOVES is being run in batch-mode, or if multiple runs are being saved to the

same output database, the user should make sure to separate link emissions in the result

database by “MOVESRunID” or “monthID, dayID, hourID.” Aggregating separate

runs will result in incorrect emission rates.

This concludes the discussion on how to generate project-level CO emission rates using

MOVES. Please refer to the 1992 Guideline and Appendix W to 40 CFR Part 51 for

further information on how to incorporate MOVES emission rates into air quality

modeling.
32

Section 3: Example: Using MOVES for a CO Screening

Analysis of an Intersection

The following is an abbreviated example of using MOVES to calculate CO emission

rates for a portion of an intersection project. The example shown is of a single, one-way

arterial road through a signalized intersection; while real-world projects would be more

complex, this simplified example makes it easier to demonstrate the steps necessary to

calculate emission rates using MOVES.

This example does not include the subsequent air quality modeling; project sponsors

should refer to the 1992 Guideline for an example of running CAL3QHC for an

intersection project using CO emission rates.

Note also that this example includes only an intersection of the type covered by the 1992

Guideline. This example is not relevant for CO refined analyses and may not be relevant

for other types of projects. Additionally, all activity will be defined through the average

speed function of the Links Importer. It is therefore not necessary to import a Link Drive

Schedule, Op-Mode Distribution, or Off-Network table.

The following is some pertinent data about the example project being analyzed:

• The analysis is of a single intersection (see next section for details) located in a

county in a state other than California.

• The analysis month and year is January 2015.

• Meteorological data for January at this location is 25 degrees Fahrenheit and 70%

relative humidity.

• All vehicle types are present in the intersection being analyzed; however, no local

age distribution is available.

• There is an I/M program for light-duty vehicles active in the county where the

project is located.

3.1 CHARACTERIZING THE PROJECT IN TERMS OF LINKS (SECTION 2.1)

A diagram of one road involved in a proposed intersection project is shown in Figure 3.

A single free-flow approach link (Link 1) leads to a signalized intersection; vehicles idle

at the defined queue link (Link 2), and exit the intersection on the free-flow departure

link (Link 3). Vehicle volumes and average speeds are estimated to reflect typical peak

hour activity:

Link 1 (Free-flow Approach Link): 1000 vehicles per hour – 45 mph average speed

Link 2 (Queue Link): 1000 vehicles per hour – 0 mph speed (idle)

Link 3 (Free-flow Departure Link): 1000 vehicles per hour – 45 mph average speed
33

All links are at 0% grade. Approach and departure links each have a length of 300

meters. The queue link is assigned a link length of 50 meters.

Note: Since the goal of the MOVES run is to produce a grams/vehicle-mile and/or

grams/vehicle-hour emission rate(s), the exact length or volume of each link is not

important for running MOVES, although it is important for subsequent CAL3QHC

dispersion modeling.

Figure 3. Links Characterizing the Proposed Intersection

3.2 DETERMINING THE NUMBER OF MOVES RUNS (SECTION 2.2)

This example follows the 1992 Guideline by conservatively using typical peak-hour

traffic activity in one MOVES run to generate emission rates.

3.3 DETERMINE BASIC RUN SPECIFICATION INPUTS (SECTION 2.3)

When configuring MOVES for the analysis, a RunSpec is developed following the

guidance in Section 2.3:

• From the Scale menu, selecting the “Project” domain; in addition, choosing

output in “Inventory” so that total emissions are produced for each link (see

Section 2.3.2).

• From the Time Spans Panel, the appropriate year, month, day, and hour is

selected (see Section 2.3.3).

• From the Geographic Bounds Panel, the specific county is selected that contains

the project (see Section 2.3.4).

• From the Vehicles/Equipment Panel, all vehicle types and fuel types (Gasoline,

Diesel, and CNG) are selected (see Section 2.3.5).

• From the Road Types Panel, the Urban Unrestricted road type is selected (see

Section 2.3.6).
34

• From the Pollutants and Processes Panel, the pollutant/processes CO Running and

CO Crankcase Running are selected according to the guidance (see Section 2.3.7).

• In the Output Panel, an output database is specified with grams and miles selected

as units (see Section 2.3.10). Population and Distance Traveled are selected as

Activity outputs. No additional boxes are selected Output Emission Detail (some

will be automatically checked).

3.4 ENTERING PROJECT DETAILS USING PROJECT DATA MANAGER

(SECTION 2.4)

After filling out the appropriate selections in the RunSpec, the project details were

entered using the Project Data Manager.

3.4.1 Meteorology

The meteorology table was populated using the second option in Section 2.4.1 with the

average January temperature (25 degrees Fahrenheit) and relative humidity (70%). The

meteorology input table is shown in Figure 4.

Figure 4. Meteorology Input (Average January Conditions) – Intersection
35

3.4.2 Age Distribution

The default MOVES age distribution for 2015 was used. For the purposes of this

example, the latest regional emissions analysis was assumed to have used the default

MOBILE6.2 age distribution, and since no local data was available, the MOVES default

age distribution was used for the analysis based on Section 2.4.2 of the guidance (shown

in Figure 5).

Figure 5. Fleet Age Distribution (Partial) – Intersection
36

3.4.3 Fuel Supply and Formulation

As recommended in Section 2.4.3 of this guidance, the default MOVES fuel supply and

formulation were used for the analysis (Figures 6 and 7).

Figure 6. Fuel Supply Table – Intersection

Figure 7. Fuel Formulation Table – Intersection
37

3.4.4 Inspection and Maintenance (I/M)

The default MOVES I/M program was exported and evaluated for consistency with the

actual I/M program. For the purpose of this example analysis, the default program

matched the I/M program planned to be in place in the project county in 2015 and was reimported. As shown in Figure 8, the I/M program includes Unloaded Idle Test, ASM,

and OBD test types (test standards 11, 25, 51) for light duty vehicles (source types 21, 31,

and 32). The inspection frequency is annual (1) with a compliance rate of 93.12 percent.

Figure 8. I/M Program Details for Project Area
38

3.4.5 Link Source Type

The distribution of source types was defined based on the distribution of vehicles on

arterial roads used in the latest regional emissions analysis (see Figure 9). The

distribution used was identical for all links.

Figure 9. Link Source Type Input Table (Partial) – Intersection
39

3.4.6 Links

The Links table was populated with the parameters of each link (shown in Figure 10).

Links 1 and 3 (free-flow approach and departure links) were assigned a link length of 300

meters (0.1875 miles), a link volume of 1000, and an average speed of 45 mph. Link 2

was assigned a link length of 50 meters (0.016 miles), a link volume of 1000, and an

average speed of 0 mph. Since no Op-Mode distribution or Link-Drive Schedule is

defined for any of the links, MOVES will calculate emission based on average speed,

road type, and grade.

Figure 10. Links Table – Intersection
40

3.5 GENERATING EMISSION RATES FOR USE IN AIR QUALITY MODELING

(SECTION 2.5)

After running MOVES, total emission quantities (emissionQuant) for each link are

obtained from the MOVES output database table. Distance traveled is obtained from the

movesactivityoutput table (activityTypeId 1). Emission rates for free-flow links are

calculated by dividing emissionQuant by distance traveled. The emission rate for the

queue link is calculated by dividing the emissionQuant by the link volume

(activityTypeId 6) from the movesactivityoutput table. The resulting emission rates

(shown in bold in Figure 11) are 4.98 grams/vehicle-mile for the free-flow approach and

departure links (Links 1 and 3) and 19.44 grams/vehicle-hour for vehicles idling on the

queue link (Link 2). These rates can be now be used in CAL3QHC to complete this CO

screening analysis.

Figure 11. Emission Rate Calculations for Each Link – Intersection
41

Section 4: Example: Using MOVES to Calculate Start and Idle

Emission Factors for a Transit Facility

The following is an abbreviated example of using MOVES to calculate CO emission

rates for the start and idle activity (gram/vehicle-start and gram/vehicle-hour,

respectively) for passenger vehicles associated with a park-and-ride lot serving a transit

bus facility. Although this example is for the peak (or worst-case) hour, the methodology

described for calculating start and idle emission factors could apply to both screening and

refined analyses. For illustrative purposes, the passenger vehicles are assumed to be

entirely gasoline passenger cars (source type 21). Additionally, only start and idle

emissions are considered in this example. A more realistic scenario would, of course,

also include emissions associated with the transit buses entering and exiting the facility

(in addition to the emissions from the passenger vehicles). Users should refer to Section

2 of the guidance, as well as the intersection example in Section 3, for information on

how activity on free-flow and queue links would be defined for such a park-and-ride lot

and transit terminal.

Although a real-world project would likely be more complex, this simplified example

makes it easier to demonstrate the steps necessary to calculate emission rates using

MOVES.

The following is some pertinent data about the example project being analyzed:

• The analysis is of a park-and-ride lot serving a transit bus facility (see next section

for details) located in a county in a state other than California.

• The analysis month and year is January 2015.

• Meteorological data for January at this location is 25 degrees Fahrenheit and 70%

relative humidity.

• An age distribution for passenger cars is available from the latest regional

conformity analysis.

• Project engineers have estimated soak times for the cars that will use the lot based

on an analysis of similar facilities (see next section for details).

• There is no I/M program active in the county where the project is located.

4.1 CHARACTERIZING THE PROJECT IN TERMS OF LINKS (SECTION 2.1)

In order to calculate both a start emission factor and idle emission factor for passenger

cars, two links are defined. A single idle link (Link 1) is defined to represent idling

passenger cars. The start emission activity from the vehicles is defined through an offnetwork link (Link 2). The following traffic data is available for the peak hour of

activity:

Link 1 (Idle Link): 50 passenger cars idling – 0 mph average speed (idle)

Link 2 (Off-network Link): 100 starts during the peak hour
42

The lengths of the idle link and off-network link are set to 0 (as link length does not

matter). Also, both links have a 0% grade.

Passenger cars are estimated to have been “soaking” for greater than 720 minutes before

starting; that is, it has been more than 720 minutes since the cars have last started.

Note: Since the goal of the MOVES run is to produce a grams/idle-hour and

grams/vehicle-start emission rate, the exact volume of each link is not important for

running MOVES.

4.2 DETERMINING THE NUMBER OF MOVES RUNS (SECTION 2.2)

Since this is a screening analysis, this example uses peak-hour vehicle activity in one

MOVES run to generate “worst-case” emission rates.

4.3 DETERMINE BASIC RUN SPECIFICATION INPUTS (SECTION 2.3)

When configuring MOVES for the analysis, a RunSpec is developed following the

guidance in Section 2.3:

• From the Scale menu, selecting the “Project” domain; in addition, choosing

output in “Inventory” so that total emissions are produced for each link (see

Section 2.3.2).

• From the Time Spans Panel, the appropriate year, month, day, and hour are

selected (see Section 2.3.3).

• From the Geographic Bounds Panel, the specific county is selected that contains

the project (see Section 2.3.4).

• From the Vehicles/Equipment Panel, the Gasoline Passenger Car source type

(sourceType 21) is selected (see Section 2.3.5).

• From the Road Types Panel, the Off-Network and Urban Unrestricted road types

are selected (see Section 2.3.6).

• From the Pollutants and Processes Panel, the pollutant/processes CO Starts, CO

Crankcase Starts, CO Running, and CO Crankcase Running are selected

according to the guidance (see Section 2.3.7).

In the Output Panel, an output database is specified with grams and miles selected

as units (see Section 2.3.10). Population is selected as an Activity output. No

additional boxes are selected Output Emission Detail (some will be automatically

checked).
43

4.4 ENTERING PROJECT DETAILS USING PROJECT DATA MANAGER

(SECTION 2.4)

After filling out the appropriate selections in the RunSpec, the project details were

entered using the Project Data Manager.

4.4.1 Meteorology

The meteorology table was populated using the second option in Section 2.4.1 with the

average January temperature (25 degrees Fahrenheit) and relative humidity (70%). The

meteorology input table is shown in Figure 12.

Figure 12. Meteorology Input (Average January Conditions) – Terminal
44

4.4.2 Age Distribution

An age distribution table was used that reflects the passenger car fleet accessing the parkand-ride lot (see Figure 13). In this example, the age distribution used is based on the

latest regional SIP, as discussed in Section 2.4.2 of the guidance.

Figure 13. Fleet Age Distribution – Terminal
45

4.4.3 Fuel Supply and Formulation

As recommended in Section 2.4.3 of this guidance, the default fuel supply and fuel

formulation were used for the county containing the project (Figures 14 and 15). Fuel

formulation 3889 is a gasoline with a 10 percent ethanol blend and a RVP of 14.5.

Figure 14. Fuel Supply Table – Terminal

Figure 15. Fuel Formulation Table – Terminal
46

4.4.4 Inspection and Maintenance (I/M)

It was not necessary to input an I/M program since there was no program in the county

containing the project.

4.4.5 Link Source Type

A source type distribution was defined for the idle link. All activity is from passenger

cars (sourceType 21 - see Figure 16). It is unnecessary to include the source type

distribution for the starting vehicles on the Off-Network link (Link 2); this will be

defined in the Off-Network Table (see Section 4.4.7).

Figure 16. Link Source Type Input Table – Terminal

4.4.6 Links

The Links table was populated with the parameters of each link (shown in Figure 17). To

reflect the previously described peak hour activity, Link 1 (idle link) was assigned a link

length of 0 miles, a link volume of 50, and an average speed of 0 mph. Link 2 (offnetwork link) was assigned a link length of 0 miles, a link volume of 100, and an average

speed of 0 mph.

Figure 17. Links Table – Terminal
47

4.4.7 Off-Network and Op-Mode Distribution

Information on start activity is defined through both the Off-Network and Op-Mode

Distribution tables. First, the Source Type and Link Volume are defined in the OffNetwork Table (Figure 18) with a start fraction of 1 (indicating that all 100 vehicles are

starting during the hour). The extended idle fraction and parked vehicle fraction are set

to 0.28

Figure 18. Off-Network Table

The soak distribution (the time spent parked before starting) is defined in the Op-Mode

Distribution Table. As noted in Section 4.1, for this specific project, all passenger cars

have been parked for greater than 720 minutes prior to starting. As shown in Figure 19,

the OpModeID corresponding to this soak time is OpModeID108. Start emissions for

CO come from both the start exhaust process (polProcess 202), as well as the crankcase

start process (polProcess 216). A fraction of 1 for OpModeID 108 is defined for each

pollutant process.

Figure 19. Op-Mode Distribution Table – Terminal

28 Note: the “Extended Idle Fraction” field is only relevant for Long-Haul Combination Diesel Trucks. See

Section 2.3.3.4.16 of the MOVES User Guide for more information.
48

4.5 GENERATING EMISSION RATES FOR USE IN AIR QUALITY MODELING

(SECTION 2.5)

After running MOVES, total emission quantities (emissionQuant) for each link are

obtained from the MOVES output database. These values are the equivalent of a

grams/hour emission factor for each link. However, as shown in column D of Figure 20,

not all activity was used to calculate emissions from gasoline passenger cars; some

activity was assigned to diesel passenger cars.29 Since only gasoline passenger cars were

assumed to be present at the park-and-ride lot, and were selected in the RunSpec,

emissions were not calculated for all 50 idling and 100 starting vehicles.30

To get a correct aggregate gram/hour emission rate, first a gram/idle-hour and

gram/vehicle-start emission factor should be calculated. Calculating these emission

factors for individual vehicles may also add flexibility to the analysis and is useful if

there are multiple areas with idling and starting vehicles, where a per-vehicle emission

factor can be broadly applied.

The emission rates for both links are calculated by dividing the emissionQuant by the link

volume (activityTypeId 6) from the movesactivityoutput table. The resulting emission

rates (shown in bold in Figure 20) are 10.76 grams/idle-hour for the idle link (Link 1) and

140.11 grams/vehicle-start for the off-network link (Link 2).

Figure 20. Emission Rate Calculations for Each Link – Terminal

These rates can be multiplied by the actual link volumes (50 and 100, respectively) and

the results summed together to get an aggregate gram/hour emission rate. This rate can

then be used in subsequent air quality modeling to represent total emissions from the

entire area.

29 As obtained from the MOVESActivityOutput table in the MOVES output database.

30 To allocate all activity to only gasoline passenger cars, the AVFT panel of the MOVES GUI could have

been used to specify a gasoline fraction of 1.0 and a diesel fraction of 0. This would avoid activity not

being included in the emission calculations. Section 2.2.9.6 of MOVES User Guide describes this process

further.
49

Appendix: Characterizing Intersection Projects for CO

Refined Analyses Using MOVES

A.1 INTRODUCTION

This appendix expands upon the discussion in Section 2.1 on how best to characterize

links when modeling an intersection project using MOVES. The MOVES emissions

model allows users to represent intersection traffic activity with a higher degree of

sophistication compared to previous models. This appendix provides several options to

describe vehicle activity to take advantage of the capabilities MOVES offers to complete

modeling for CO refined analyses of intersection projects.

Exhibit A-1 is an example of a simple signalized intersection showing the links

developed by a project sponsor to represent the two general categories of vehicle activity

expected to take place at this intersection (approaching the intersection and departing the

intersection).

Exhibit A-1. Example of Approach and Departure Links for a Simple Intersection
50

When modeling an intersection, each approach link or departure link can be modeled as

one or more links in MOVES depending on the option chosen to enter traffic activity.

This guidance suggests three possible options for characterizing activity on each

approach and departure link when CO refined analyses are completed (such as those

shown in Exhibit A-1):

• Option 1: Using average speeds

• Option 2: Using link drive schedules

• Option 3: Using Op-Mode distributions

While Option 1 may need to be relied upon more during the initial transition to using

MOVES, as more detailed data are available to describe vehicle activity, users are

encouraged to consider using the Options 2 and 3 to take full advantage of the

capabilities of MOVES.

Once a decision has been made on how to characterize links, users should continue to

develop the remaining MOVES inputs as discussed in Section 2.4 of the guidance.

A.2 OPTION 1: USING AVERAGE SPEEDS

The first option is for the user to estimate the average speeds for each link in the

intersection based on travel time and distance. Travel time should account for the total

delay attributable to traffic signal operation, including the portion of travel when the light

is green and the portion of travel when the light is red. The effect of a traffic signal cycle

on travel time includes deceleration delay, move-up time in a queue, stopped delay, and

acceleration delay. Using the intersection example given in Exhibit A-1, each approach

link would be modeled as one link to reflect the higher emissions associated with vehicle

idling through lower speeds affected by stopped delay; each departure link would be

modeled as one link to reflect the higher emissions associated with vehicle acceleration

through lower speeds affected by acceleration delay.

A variety of methods are available to estimate average speed. Project sponsors determine

congested speeds by using appropriate methods based on best practices for highway

analyses. Some resources are available through FHWA’s Travel Model Improvement

Program (TMIP).31 Methodologies for computing intersection control delay are provided

in the Highway Capacity Manual.32

31 See FHWA’s TMIP website: http://tmip.fhwa.dot.gov/.

32 Users should consult the most recent version of the Highway Capacity Manual. As of the release of this

guidance, the latest version is the Highway Capacity Manual 2000, which can be obtained from the

Transportation Research Board (see http://144.171.11.107/Main/Public/Blurbs/152169.aspx for details).
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A.3 OPTION 2: USING LINK DRIVE SCHEDULES

A more refined approach is to enter vehicle activity into MOVES as a series of link drive

schedules to represent individual segments of cruise, deceleration, idle, and acceleration

of a congested intersection. A link drive schedule defines a speed trajectory to represent

the entire vehicle fleet via second-by-second changes in speed and highway grade.

Unique link drive schedules can be defined to describe types of vehicle activity that have

distinct emission rates, including cruise, deceleration, idle, and acceleration.

Exhibit A-2 illustrates why using this more refined approach can result in a more detailed

emissions analysis. This exhibit shows the simple trajectory of a single vehicle

approaching an intersection during the red signal phase of a traffic light cycle. This

trajectory is characterized by several distinct phases (a steady cruise speed, decelerating

to a stop for the red light, idling during the red signal phase, and accelerating when the

light turns green). In contrast, the trajectory of a single vehicle approaching an

intersection during the green signal phase of a traffic light cycle is characterized by a

more or less steady cruise speed through the intersection.

Exhibit A-2. Example Single Vehicle Speed Trajectory Through a Signalized

Intersection

0

5

10

15

20

25

30

35

40

45

50

-100 -80 -60 -40 -20 0 20 40 60 80 100

Speed (mph)

Distance (m)

Cruise Decelerate Idle Accelerate Cruise

Red Light

Green Light

For the example intersection in Exhibit A-1, link drive schedules representing the

different operating modes of vehicle activity on the approach and departure links can be

determined. For approach links, the length of a vehicle queue is dependent on the

number of vehicles subject to stopping at a red signal. Vehicles approaching a red traffic
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signal decelerate over a distance extending from the intersection stop line back to the

stopping distance required for the last vehicle in the queue. The average stopping

distance can be calculated from the average deceleration rate and the average cruise

speed. Similarly, for the departure links, vehicles departing a queue when the light turns

green accelerate over a distance extending from the end of the vehicle queue to the

distance required for the first vehicle to reach the cruise speed, given the rate of

acceleration and cruise speed. Exhibit A-3 provides an illustration of how the different

vehicle operating modes may be apportioned spatially near this signalized intersection.

Exhibit A-3. Example Segments of Vehicle Activity Near a Signalized Intersection

There are other considerations with numerous vehicles stopping and starting at an

intersection over many signal cycles during an hour. For instance, heavy trucks

decelerate and accelerate at slower rates than passenger cars. Drivers tend not to

decelerate at a constant rate, but through a combination of coasting and light and heavy

braking. And acceleration rates are initially higher when starting from a complete stop at

an intersection, becoming progressively lower to make a smooth transition to cruise

speed.

In the case of an uncongested intersection, the rates of vehicles approaching and

departing the intersection are in equilibrium. Some vehicles may slow, and then speed up

to join the dissipating queue without having to come to a full stop. Once the queue

clears, approaching vehicles during the remainder of the green phase of the cycle will

cruise through the intersection virtually unimpeded.

In the case of a congested intersection, the rate of vehicles approaching the intersection is

greater than the rate of departure, with the result that no vehicle can travel through

without stopping; vehicles approaching the traffic signal, whether it is red or green, will

have to come to a full stop and idle for one or more cycles before departing the
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intersection. The latest Highway Capacity Manual is a good source of information for

vehicle operation through signalized intersections.

The emission factors obtained from MOVES for each segment of vehicle activity

obtained via individual link drive schedules are readily transferable to air quality models.

Note: For both free-flow highway and intersection links, users may directly enter output

from traffic simulation models in the form of second-by-second individual vehicle

trajectories. These vehicle trajectories for each road segment can be input into MOVES

using the Link Drive Schedule Importer and defined as unique LinkIDs. There are no

limits in MOVES as to how many links can be defined; however, model run times

increase as the user defines more links. A representative sampling of vehicles can be

used to model higher volume segments by adjusting the resulting sum of emissions to

account for the higher traffic volume. For example, if a sampling of 5,000 vehicles

(5,000 links) was used to represent the driving patterns of 150,000 vehicles, then the sum

of emissions would be adjusted by a factor of 30 to account for the higher traffic volume

(i.e., 150,000 vehicles/5,000 vehicles). Since the vehicle trajectories include idling,

acceleration, deceleration, and cruise, separate roadway links do not have to be

explicitly defined to show changes in driving patterns. The sum of emissions from each

vehicle trajectory (LinkID) represents the total emission contribution of a given road

segment.

A.4 OPTION 3: USING OP-MODE DISTRIBUTIONS

A third option is for a user to generate representative Op-Mode distributions for approach

and departure links by calculating the fraction of fleet travel times spent in each mode of

operation. For any given signalized intersection, vehicles are cruising, decelerating,

idling, and accelerating. Op-Mode distributions can be calculated from the ratios of

individual mode travel times to total travel times on approach links and departure links.

This type of information could be obtained from Op-Mode distribution data from (1)

existing intersections with similar geometric and operational (traffic) characteristics, or

(2) output from traffic simulation models for the proposed project or similar projects.

The following methodology describes a series of equations to assist in calculating vehicle

travel times on approach and departure links. Note that a single approach and single

departure link should be defined to characterize vehicles approaching, idling at, and

departing an intersection (e.g., there is no need for an “idling link,” as vehicle idling is

captured as part of the approach link).
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A.4.1 Approach links

When modeling each approach link, the fraction of fleet travel times in seconds (s) in

each mode of operation should be determined based on the fraction of time spent

cruising, decelerating, accelerating, and idling:

Total Fleet Travel Time (s) = Cruise Time + Decel Time + Accel Time +

Idle Time

The cruise travel time can be represented by the number of vehicles cruising multiplied

by the length of approach divided by the average cruise speed.

Cruise Time (s) = Number of Cruising Vehicles * (Length of Approach (mi) ÷

Average Cruise Speed (mi/hr)) * 3600 s/hr

The deceleration travel time can be represented by the number of vehicles decelerating

multiplied by the average cruise speed divided by the average deceleration rate:

Decel Time (s) = Number of Decelerating Vehicles * (Average Cruise Speed

(mi/hr) ÷ Average Decel Rate (mi/hr/s))

The acceleration travel time occurring on an approach link can be similarly represented.

However, to avoid double counting acceleration activity that occurs on the departure link,

users should multiply the acceleration time by the proportion of acceleration that occurs

on the approach link (Accel Length Fraction on Approach):

Accel Time (s) = Number of Accelerating Vehicles * (Average Cruise Speed

(mi/hr) ÷ Average Accel Rate (mi/hr/s)) * Accel Length Fraction on

Approach

The idle travel time can be represented by the number of vehicles idling multiplied by the

average stopped delay (average time spent stopped at an intersection):

Idle Time (s) = Number of Idling Vehicles * Average Stopped Delay (s)

Control delay (total delay caused by an intersection) may be used in lieu of average

stopped delay, but control delay includes decelerating and accelerating travel times,

which should be subtracted out (leaving only idle time).

After calculating the fraction of time spent in each mode of approach activity, users

should select the appropriate MOVES Op-Mode corresponding to each particular type of

activity (see Section 2.4.8 for more information). The operating modes in MOVES

typifying approach links include:

• Cruise/acceleration (OpModeID 11-16, 22-25, 27-30, 33, 35, 37-40);

• Low and moderate speed coasting (OpModeID 11, 21); and
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• Idling (OpModeID 1)

The relative fleet travel time fractions can be allocated to the appropriate Op-Modes in

MOVES. The resulting single Op-Mode distribution accounts for relative times spent in

the different driving modes (cruise, deceleration, acceleration, and idle) for the approach

link.

A.4.2 Departure links

When modeling each departure link, the fraction of fleet travel times spent in each mode

of operation should be determined based on the fraction of time spent cruising and

accelerating:

Total Fleet Travel Time (s) = Cruise Time + Accel Time

The cruise travel time can be represented by the number of vehicles cruising multiplied

by the travel distance divided by the average cruise speed:

Cruise Time (s) = Number of Cruising Vehicles * (Length of Departure (mi)) /

(Average Cruise Speed (mi/hr)) * 3600 s/hr

The acceleration travel time occurring during the departure link can be represented by the

number of vehicles accelerating multiplied by the average cruise speed divided by the

average acceleration rate. However, to avoid double counting acceleration activity that

occurs on the approach link, users should multiply the resulting acceleration time by the

proportion of acceleration that occurs on the departure link (Accel Length Fraction on

Departure):

Accel Time (s) = Number of Accelerating Vehicles * (Average Cruise Speed

(mi/hr) ÷ Average Accel Rate (mi/hr/s)) * Accel Length Fraction on

Departure

After calculating fraction of time spent in each mode of departure activity, users should

select the appropriate MOVES Op-Mode corresponding to each particular type of activity

(see Section 2.4.8 for more information). The operating modes typifying departure links

include:

• Cruise/acceleration (OpModeID 11-16, 22-25, 27-30, 33, 35, 37-40)

The relative fleet travel time fractions can be allocated to the appropriate Op-Modes. The

resulting single Op-Mode distribution accounts for relative times spent in the different

driving modes (cruise and acceleration) for the departure link.