APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 1 

APPENDIX 4. 

TRAVEL DEMAND MODEL METHODOLOGY AND AIR 

QUALITY CONFORMITY ANALYSIS

Contents 

Section 1 - Travel Demand Forecast Model Procedures and Assumptions 

Section 2 - Population and Employment Forecasts 

Section 3 - The Air Quality Conformity Process 

Section 4 - Transportation Analysis Zones, Network and Travel Demand Model 

Section 5 - Travel Demand Model Results and Regional Travel 

Section 6 - Carbon Monoxide Mobile Source Emissions Forecasts 

Section 7 - PM10 Modeling Assumptions 

Section 8 - Ozone Modeling Assumptions 

Section 9 - Finding of Air Quality Conformity 

Section 10 - Transportation Control Measures 

Section 11 - Conformity Analysis Index 

Appendix 4-A - RTC 2004 Regional Travel Demand Model Package 2 –Transit 

 Processing and Mode Choice Modeling Capabilities 

Appendix 4-B - NDOT’s Traffic Volume Projections for Externals. 

1. Travel Demand Forecast Model Procedures and Assumptions 

Background 

The Las Vegas Regional Travel Demand Forecast Model follows established 

professional practice through the implementation of the conventional “four step” travel 

demand forecasting process. The first step is known as Trip Generation, in which 

person trips produced in and attracted to each zone are calculated from the estimates of 

population, employment and other socio-economic variables discussed in Appendix 

3.Regional Forecasts. In the second step known as trip distribution, these productions 

and attractions are associated with each other through algorithms that develop a pattern 

of zone-to-zone movements. In the third step, Mode Choice, the zone-to-zone person 

trip estimates are converted into auto trips based on average vehicle occupancy rate 

and person transit trips. In the final step, the demand for vehicle travel is assigned to 

the street network to give estimates of traffic flow and the demand for transit is assigned 

to the transit routes to give transit ridership estimates. 

 

The Regional Transportation Commission Travel Demand Model (RTC Model) 

calculations are performed using the TRANSCAD software package developed by the 

Caliper Corporation of Newton, Massachusetts. The RTC model was converted and 

has incorporated a series of improvements over years. Table1. below provides the 

current RTC 2004 Model chronology and components, and the evolutions of the main 

input assumptions and the model procedures. 
 2 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 1. Model Chronology 

Name of Model Developer Release 

Date 

Software 

Platform 

Calibration 

Year 

# of 

TAZs

Features Utilized by 

RTC 2004 Model 

Resort Corridor 

MIS Interim Mode 

Choice 

Parsons 

Brinkerhoff 

Quade & 

Douglas 

1995 Tranplan 1995 751 Model structure and mode 

choice model 

Las Vegas Travel 

Demand Model 

Parsons 

Brinkerhoff 

Quade & 

Douglas 

2000 Tranplan 1995 1140 Visitor trip generation 

models; visitor distribution 

models; other trip matrix; 

Use of trip rates developed 

from the 1996 household 

travel survey, Improved 

estimation of visitor trips 

using data from the 1996 

visitor and airport surveys, 

RTC Las Vegas 

Phase I Model 

Caliper 

Corporation 

2002 TransCAD 

4.0 

2000 1140 Time of day distribution; 

highway skims; feedback 

looping, Locating and 

coding of over 800 traffic 

count locations and 40 

screen lines for use in 

model calibration, 

RTC Las Vegas 

Phase I Model 

Update 

Caliper 

Corporation 

2003 TransCAD 

4.6 

2000 1218 TAZ structure; employment 

planning variables; highway 

network; highway 

assignment; cold start flows 

and VMT 

RTC Phase 1A 

Regional Travel 

Model 

Parsons 

Corporation 

2003 TransCAD 

4.6 

2000 1218 Household planning 

variables; highway network 

classification; resident 

socioeconomic sub-models; 

resident trip generation 

models; resident trip 

distribution models; auto 

occupancy models 

RTC 2004 Model 

(Update Package 

1) 

Parsons 

Corporation 

2006 TransCAD 

4.7 

2002/2003 1219 Updated planning variables; 

updated highway networks; 

updated link capacities; 

added special generators; 

initialized travel times; 

updated time of day 

distributions; updated 

transit share matrix 

RTC 2004 Model 

(Update Package 

2A) 

Parsons 

Corporation 

2008 TransCAD 

4.8 

2002/2003 1645 Added additional and 

optional capabilities, 

including transit network 

and path-building 

processing, Mode Choice 

modeling, HOV procedures 

and transit assignment 

procedures. Added TAZs 

(1635 internal TAZs) to 

enlarge the modeling area, 

including Bounder City 

area; Updated planning 

variables; updated highway 

networks. 

Source: Regional Transportation Commission of Southern Nevada 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 3 

RTC Regional Travel Demand Model (without Mode Choice Element) Flow Chart 1. 
 4 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

RTC Regional Travel Demand Model (without Mode Choice Element) Flow Chart 2. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 5 

The major latest model and zone system updates include: 

• Added additional and optional capabilities, including transit network and pathbuilding processing, Mode Choice modeling, HOV procedures and transit 

assignment procedures. 

• Enlarge and Refinement of the zone system to include Boulder City, Apex area 

for the City of North Las Vegas and some other areas; increase the number of 

zones from 1219 to 1645 (1635 internal zones plus 10 external zones), 

• Addition of network links, 

An important part of the model improvement process has been a regular program of 

inter-agency consultation among the RTC, local entities and the Nevada Department of 

Transportation (NDOT). This was accomplished previously through the establishment 

of the Travel Demand Forecasting and Modeling Subcommittee (TDFMS) and later has 

been accomplished through the monthly Modeling Working Group meetings. Many of 

the changes made have been discussed and refined through this process. 

The latest version of the updated RTC model is named as RTC 2004 Model (Package 

2A), it is employed in this TIP and RTP development and air quality conformity 

determinations. For the whole RTC model structure, refer to Appendix II B Travel 

Demand Model Documentation, Regional Transportation Plan FY 2006-2030 October 

2006, by Regional Transportation Commission. For documentation about the Mode 

Choice, HOV procedures and Transit Assignment procedures included in the RTC 2004 

Pack 2A, see Appendix A RTC 2004 Regional Travel Demand Model Package 2 –

Transit Processing and Mode Choice Modeling Capabilities at the end of this document. 

2. Population and Employment Forecasts 

2.1 Background 

The key planning assumptions made as a foundation for the air quality emissions 

analysis and Conformity Finding relate to the projection of future land use, population 

and employment. These projections are used to determine future travel demand and 

travel patterns and the effect these will have on mobile source emissions. 

Recognizing the complexity of land use forecasting, the Southern Nevada Regional 

Planning Coalition (SNRPC)1

 formed a Land Use Working Group (LUWG) at the 

request of Regional Transportation Commissions of Southern Nevada (RTC). LUWG is 

responsible for providing forecasted land use activity for the RTC. The LUWG consists 

of planning staff from Clark County and the cities of Las Vegas, North Las Vegas, and 

Henderson. In accordance with inter-local agreement and established practice, the 

population and employment projections used in this analysis are based upon those 

 

1

 In its 1997 session, the Nevada State Legislature enabled the formation of the Southern Nevada 

Regional Planning Authority (SNRPA). There are ten members in the Coalition membership and Board. 

Two elected officials are appointed by the governing body of each public entity (except Boulder City and 

the Clark County School District with one appoint member each). The SNRPC conducts some of its 

business through subcommittees. 
 6 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

developed by Clark County and local government land use planning staff. The total 

projections then were matched to the total projections by the Center for Business and 

Economic Research at the University of Nevada, Las Vegas (CBER). For the detailed 

development of the Planning Variable (Land use, Population, Employment, etc.), refer to 

Appendix 3 of this RTP. 

2.2 Clark County and Regional Population and Employment Forecasts 

The CBER forecasts are for Clark County as a whole. The TDF model covers the area 

generally known as the Las Vegas Valley, comprising the Cities of Las Vegas, North 

Las Vegas and Henderson as well as those parts of unincorporated Clark County lying 

within the Bureau of Land Management Cooperative Land Sale and Exchange Area as 

designated by the Southern Nevada Public Land Management Act of 2002 displayed in 

Figure 1-4 as the BLM Disposal Boundary (2002). The Las Vegas Non-Attainment Area 

is defined as Hydrographic Basin 212, which is centered on the Las Vegas Valley. It 

includes bordering upland and mountain areas that are mostly uninhabited and that are 

held as open and recreational lands by various Federal and State agencies. The few 

settlements within these outlying areas have a total population of less than 2,000. In 

developing the CO SIP, it was agreed between the local air planning agency and the US 

EPA that it was acceptable to use the modeled area as a basis for estimating the mobile 

source emissions to be used in setting the mobile source emissions budget and in 

subsequent conformity determinations. 

Most of the population in Clark County is concentrated in the Las Vegas Valley. Based 

upon analyses performed in the mid-1990s, it has been estimated that 95 percent of the 

population of the County lives within the valley. This percentage is embodied in a 

number of inter-local agreements by various agencies involved in planning activity, 

including Clark County’s Planning Department, the School District, the RTC, the 

Southern Nevada Regional Planning Coalition and the Southern Nevada Water 

Authority, and it is, therefore, used to calculate the population control total for the Las 

Vegas Valley in the travel demand forecasting and air quality conformity process.

The future year land use forecast was created through the work of Southern Nevada 

Regional Planning Coalition (SNRPC) Land Use Workgroup (LUWG) with the members 

representing the cities of Las Vegas, North Las Vegas, Henderson, urbanized Clark 

County and the RTC. The Workgroup was formed to develop a consensus based 

process to define future land use development plans for the RTC’s transportation 

planning process. Based on the available vacant land of the Assessor’s 2006 closed roll 

parcel, the group created GIS data of planned land development using the RTC/SNRPC 

planned land use development definition. This future land use is in 5-year increments by 

jurisdiction covering the years from 2005 through 2035. Table 2 sets out the forecast 

developed acres for 2005 to 2030. 

There are two parts to the development of the land use forecast: 1) determining the 

current and future land use development patterns and 2) converting the land use 

patterns to the planning variables (PV) that are inputs to the travel demand forecast 

model. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 7 

Table 2. Forecast Developed Acres, 2005-2030 

Forecast Growth Acres Time Period 

Residential Non-Residential Total 

2006-2010 15,558 16,214 31,771 

2010-2015 16,212 15,092 31,304 

2015-2020 16,565 15,664 32,229 

2020-2025 9,900 9,900 19,800 

2025-2030 4,900 4,972 9,872 

Total 63,136 61,841 124,977 

Non-Residential includes open space 

Source: Regional Transportation Commission, Planning Variable Development and Methodology, 2008. 

Table 3. Summary of Planning Variables 2005 -2030 

FIELD Year 2005 Year 2008 Year 2013 Year 2020 Year 2030 

2013 

% of 

2008 

2020 

% of 

2008 

2030 

% of 

2008 

POP 1,769,532 2,022,523 2,431,048 2,877,544 3,230,493 120% 142% 160%

DU 686,226 780,260 938,335 1,120,702 1,233,422 120% 144% 158%

ODU 656,743 746,472 896,869 1,069,077 1,172,324 120% 143% 157%

HH_SIZE 3,051 3,050 3,183 3,507 3,869 104% 115% 127%

TOTEMP 829,586 965,359 1,168,664 1,418,536 1,653,399 121% 147% 171%

HOTEL 249,561 285,419 338,519 384,933 406,583 119% 135% 142%

OFFICE 141,134 164,552 202,971 252,978 286,311 123% 154% 174%

INDUST 123,672 147,614 184,468 237,792 317,241 125% 161% 215%

OTHER_NON 167,735 195,641 231,207 290,612 364,429 118% 149% 186%

RETAIL 147,484 172,133 211,498 252,221 278,835 123% 147% 162%

NAFB 12,000 13,200 14,600 15,000 15,000 111% 114% 114%

MIA_EMP 16,569 18,250 21,222 21,117 21,117 116% 116% 116%

MIA_PASS 121,423 134,295 154,626 144,247 144,247 115% 107% 107%

IVPH_EMP 0 300 3,200 5,117 8,177 1067% 1706% 2726%

IVPH_PASS 0 0 0 42,059 67,213 

UNLV_MAIN_EMP 2,570 2,807 3,299 3,521 3,521 118% 125% 125%

UNLV_MAIN_ENR 28,104 30,809 36,286 38,734 38,734 118% 126% 126%

UNLV_NLV_EMP 0 0 0 1,000 3,000 

UNLV_NLV_ENR 0 0 0 10,000 30,000 

NEV_ST_COLL_EMP 103 161 275 450 750 171% 279% 465%

NEV_ST_COLL_ENR 1,562 3,025 6,400 12,000 20,000 212% 397% 661%

F18 206,888 216,320 231,938 253,308 262,608 107% 117% 121%

F912 75,282 77,994 84,662 96,002 101,402 109% 123% 130%

F13 29,587 31,428 33,528 35,000 35,000 107% 111% 111%

MED_INC 60,755,187 60,755,187 60,755,187 60,755,187 60,755,187 100% 100% 100%

Source: Regional Transportation Commission staff. 

Table 3. is the summary of the key PVs for the TDF model. The first column has the 

variable names to be used in the model. Refer to the RTC travel demand model 

document for detailed planning variable definitions. The green colored columns show 

the variable totals for the modeling horizon years (2013, 2020 and 2030) for the RTP 
 8 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

2009-2030. The graph below shows the population, occupied dawdling units 

(households) and total employment growths for the plan forecast horizon years. 

Population, Households and Total Employment

0 2013 2020 2030

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

1

RTP Horizon Years

Estimated Model Input

Year

POP

ODU

TOTEMP

Source: Regional Transportation Commission staff. 

In addition to total population, households and employment, the model utilizes certain 

other socio-economic indicators. These include average household income, school 

enrollment, and various classes of employment. The number of dwellings in each zone 

was estimated from land use data on the extent of residential land, using density and 

occupancy factors derived from the 2000 Census and local entity sources. Average 

household income and school enrollment were also developed from local sources. A 

detailed description of the methodology is provided in Appendix III. 

3. The Air Quality Conformity Process and Travel Demand Results 

3.1. Introduction 

This section describes the air quality conformity analysis conducted as part of the 

development of the Regional Transportation Plan 2009-2030 (RTP) and the 

Transportation Improvement Program for Fiscal Years 2009-2012 (TIP). 

The Las Vegas region is in non-attainment for three pollutants: carbon monoxide (CO), 

particulate matter 10 microns in size or less (PM10), and Ozone (O3). Non-attainment is 

the term used to describe levels of these pollutants that the U.S. Environmental 

Protection Agency (EPA) has designated as not meeting the clean air standards for that 

pollutant as defined in the National Ambient Air Quality Standards (NAAQS). 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 9 

Figure 1. shows Clark County Boundary, RTC TAZ and road network, and the study 

boundaries for each pollutant. Within Clark County, the area defined as Hydrographic 

Basin 212 is designated as a non-attainment area for two pollutants – CO and PM10. 

This area is roughly coincidental with the Las Vegas Valley. On September 15, 2004 

the EPA designated about 60 percent of Clark County as non-attainment for O3. This 

area extends from the Las Vegas Valley south and east to the Colorado River. 

The Clean Air Act Amendments of 1990 (CAAA) require that each non-attainment area 

and pollutant be addressed by a control plan, referred to as the State Implementation 

Plan (SIP), developed by the state air quality planning agency. The SIP sets out policies 

and actions to ensure that air quality meets the NAAQS within a time frame determined 

under EPA regulations. In southern Nevada, responsibility for developing the SIP is 

delegated by the State of Nevada to Clark County. The Clark County Department of Air 

Quality and Environmental Management (DAQEM) is tasked with SIP development. 

Under the provisions of the CAAA, the RTC, as the MPO for the region, is the agency 

responsible for making the determination of conformity. 

Much of these regulated pollutants is produced by automobiles and other road 

transportation, so are classified as “mobile source emissions”. Any RTP/TIP must 

include a determination that implementation will result in reduction of these pollutants to 

acceptable levels in ways that conform to the SIP. The term “conformity” describes the 

determination of this acceptable result. Supporting the determination is a complex 

modeling process that is based on assumptions about what happens if existing 

conditions are extended into the future and about what happens if the projects and 

programs in the RTP/TIP are implemented. A conforming RTP/TIP model outcome 

projects that the regulated pollutants will be reduced to acceptable levels within time 

frames that meet the NAAQS. 

3.2. Conformity Guidelines 

This Section outlines the complex technical evaluation process involved in the 

conformity demonstration. Descriptions of other aspects of the process are provided in 

the Appendices, including a list of the projects included in the Travel Demand Model 

and details of the Air Quality and Transportation Control Measures assumed in the 

Model. 

RTC's Vision Statement is to provide “a safe, clean, effective regional transportation 

system that enhances mobility and air quality for our citizens and visitors”. To that end, 

the Commission has adopted the following goal for the transportation planning process: 

“Implement transportation systems that improve air quality”
 10 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Figure 1. Clark County and RTC Non-attainment Areas 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 11 

The specific procedures for reaching this goal are those established under Federal law 

for ensuring conformity between transportation plans and air quality improvement plans. 

This process of conformity is intended to ensure that the projects and programs 

proposed in the RTP, TIP and TIP amendments conform to the purpose of the CAAA 

and the SIPs. This means “...conformity to the (implementation) plan’s purpose of 

eliminating or reducing the severity and number of violations of the national ambient air 

quality standards and achieving expeditious attainment of such standards...”. The 

provisions of the CAAA in relation to conformity are amplified in the US Environmental 

Protection Agency (EPA) Final Rule, 40 CFR Part 93, as amended September 15, 

1997. The conformity determination described in this section was performed in 

accordance with US DOT and EPA guidance and procedures, and also in accordance 

with the Transportation Conformity SIP, “Transportation Conformity Plan for the Las 

Vegas Valley Nonattainment Area”, Clark County Board of Commissioners, 2008 

A. State Implementation Plans 

The State Implementation Plan (SIP) is a federally required document that defines 

strategies to ensure the existing and future attainment of the National Ambient Air 

Quality Standards (NAAQS) as defined by the United States Environmental Protection 

Agency (EPA). For metropolitan planning organizations, like the RTC of Southern 

Nevada, the SIP also establishes a mobile source emissions budget that is used in the 

evaluation of transportation plan conformity. A transportation plan is in conformance 

with the objectives of the SIP when the predicted tailpipe emissions from all travel, as 

defined in the long-range plan, is at or below the budget thresholds for all of the horizon 

years that comprise the RTP. 

The Las Vegas area is in non-attainment for PM10, Carbon Monoxide, and ozone and 

has approved SIPs for PM10 and CO. On July, 9, 2004, the EPA granted approval of 

the PM10 SIP. In February of 2006, the Clark County Department of Air Quality and 

Environmental Management submitted a CO SIP Revision to the EPA approved CO SIP 

(November 2004) to reflect changes in the EPA modeling process for defining tailpipe 

emission and to revise the mobile source emission budgets accordingly. The EPA 

approved the 2006 CO SIP revision on August 7, 2006, with an effective date (date as 

which the budgets can be used for Conformity) of September 6, 2006. 

The DAQEM is in the process of developing an Early Progress Plan (EPP) for ozone 

and expects to submit the document to the EPA in the fall of 2008. In the meantime, the 

RTC will utilize the EPA approved "Action versus No-Build" test for defining conformity 

for this pollutant, as there is currently no approved mobile source emission budget or 

SIP. 

B. Regional Emissions Analysis: Budgets for CO, PM10 and Ozone 

The principal step toward making a conformity determination is to demonstrate that the 

anticipated levels of atmospheric pollution which will result from planned and 

programmed transportation projects will be less than the relevant budget defined in the 

State Implementation Plan. 
 12 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

The CO SIP budgets for mobile source emissions are shown on Table 4. 

Table 4. Mobile Source CO Emissions Budgets for the Las Vegas Valley

Year CO Emissions Budget (tons per day) 

2006 623 

2010 690 

2015 768 

2020 817 

Source: Clark County DAQEM, Carbon Monoxide Modeling and SIP Update, August 2006 

For PM10, the SIP budget established for 2003 to demonstrate reasonable further 

progress (RFP) towards attainment of the 24-hour standard, and the budget established 

for the attainment year of 2006 apply to the conformity determination and are set out in 

Table 5. 

Table 5. Mobile Source PM10 Emissions Budgets for the Las Vegas Valley

Year PM10 Emissions Budget (tons per day) 

2003 155.77 (24-hour RFP) 

2006 141.41 (24-hour standard) 

 Source: Clark County DAQEM 

As defined earlier in this document, the DAQEM will submit an Early Progress Plan 

(EPP) for O3 to the EPA. The O3 EPP will include a mobile source emission budget for 

conformity. Prior to approved budgets, marginal and below areas may choose between 

two measures of conformity: 

• The “build-no-greater than no-build” test, a test shows that forecasts of the levels 

of O3 resulting from the planned projects and programs will be no worse than 

doing nothing, and 

• The “no greater than 2002” test, a test shows that forecasts of the levels of O3

will not be any worse than they were in 2002. 

3.3. Regional Emissions Analysis 

A. Consultation on Conformity Procedures 

The technical procedures used to determine the SIP budgets and to demonstrate 

conformity are developed in conjunction with local entities through the DAQEM 

Technical Advisory Committee (TAC). 

DAQEM’s TAC reports to the Executive Advisory Committee of the Clark County Board 

of Commissioners. This technical committee consists of staff representatives from 

Clark County, the RTC, the Cities of Boulder City, Henderson, Las Vegas and North Las 

Vegas, and the NDOT, as well as members from industry and from the public. The 

DAQEM website is at http://www.co.clark.nv.us/air_quality/index.htm. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 13 

Consultation between local and Federal agencies is maintained through the 

inter-agency consultation procedures contained in the Transportation Conformity SIP,

“Transportation Conformity Plan for the Las Vegas Valley Nonattainment Area”, Clark 

County Board of Commissioners, January 2008. These procedures include periodic 

meetings of the Air Quality Conformity Working Group. 

The Air Quality Conformity Working Group meets monthly and discusses a variety of 

topics related to air quality issues. It consists of representatives from each of RTC’s 

member entities, in addition to representatives of the Federal Highway Administration, 

Federal Transit Administration, and the EPA. The main focus of these meetings is to 

avoid delay in the conformity process by coordinating air quality and conformity 

discussions. 

B. Horizon Analysis Years 

Under Federal Regulations, conformity has to be determined for a series of “Horizon” 

years. These must include the designated attainment year, if applicable, and the last 

year of the Transportation Plan and they must be not more than 10 years apart. For this 

conformity determination, the following horizon years are used: 2013, 2020 and 2030 

for all three pollutants. 

A second component of a conformity determination is an assessment of the progress in 

implementing TCMs. These measures are intended to reduce emissions or 

concentrations of pollutants from transportation sources by reducing vehicle use or 

otherwise reducing vehicle emissions. 

As part of the conformity process, the RTC has to certify that TCMs identified in the 

SIPs are being implemented on schedule and that no federal funds are being diverted 

from these projects in such a way as to delay their timely implementation. The scope 

and status of TCMs is further discussed in Section 10 of this document with additional 

details. 

C. Conformity Determination Technical Methodology 

The calculation of mobile source emissions for each horizon year involves several 

steps, and these are described in the remaining sections of this chapter, as follows: 

• The underlying assumptions regarding population and employment change in the 

region are outlined in the previous section. 

• All regionally significant transportation projects are included in the Travel 

Demand Forecast (TDF) model, which is then used to forecast vehicle miles of 

travel (VMT) and travel speeds in the region. 

• The Mobile 6.2 emission model is then used to develop emission factors for CO, 

VOC and NOx (the later two pollutants are two major components of Ozone O3), 

that indicate how much pollutant are produced for each vehicle mile of travel. 

These factors are applied to the forecasts from the travel demand model to 

derive the modeled total of mobile source CO, VOC, NOx emissions. 
 14 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

• The emission benefits from the TCMs are then subtracted from the modeled 

vehicle emissions to produce a forecast of net mobile source emissions. 

• The procedures for establishing PM10 concentrations are described later. 

The predicted net CO, PM10 and O3 emissions that result from these procedures are 

then compared with the mobile source emissions budgets described above. The results 

are set out in Sections 6, 7, 8 and 9. 

4. Transportation Analysis Zones, Network and Travel Demand Model 

4.1. Transportation Analysis Zones 

As noted in sub-section 1.1 and 1.2., the socio-economic data used in the model is 

disaggregated into 1635 internal Transportation Analysis Zones (TAZs). There are 10 

external zones. The total modeling area has been expanded to cover the core areas of 

the Bounder City, areas north and northwest to the City of North Las Vegas, industrial 

area northeast to the City of North Las Vegas, and areas around Ivanpah Airport. Most 

TAZs are bounded by highway or major streets. Railroads and natural barriers such as 

major washes are also used to define zone boundaries. Zones range from 0.25 to 0.5 

sq. mile in most of the developed parts of the region and often 1 sq. mile in the suburbs. 

4.2. Model Networks 

The travel demand modeling process begins with the identification of the streets and 

highways to be included in the network. The model network includes all roads that are 

federally classified as collectors or above, as well as streets that are included in the 

consolidated Master Plan for Streets and Highways for the Las Vegas Valley. Each link 

in the network is defined by a number of attributes. The main attributes are: 

• Link length 

• Number of lanes (*) 

• Posted speed limits (*) 

• Roadway group 

• Area type 

• Free-flow speed 

• Capacity and 

• Speed-capacity equation coefficients. 

The attributes denoted by an asterisk are coded using a variety of sources, including 

geographic files maintained by the Clark County GIS Management Office (GISMO), 

survey photography, local entity records and field checking. Network roads are grouped 

into 11 facility types and four area types. These classifications are used to enter default 

values for other roadway attributes such as free-flow speed and capacity and also to 

summarize system performance. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 15 

Figure 2. Travel Demand Analysis Zones 
 16 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

The roadway facility types are based on generalized descriptions of the type of facility. 

They include: 

• Interstates 

• Other freeways 

• High-Occupancy Vehicle (HOV)lanes, 

• Expressways / Beltways 

• Two classes of arterial roads (Major and Minor) 

• Collectors 

• Local roads 

• Other roads used by transit 

• Two classes of ramps (Ramp and System Ramp) 

• Zone centroid connector links 

• External connector links 

The four area types are: 

• Central Business District of the City of Las Vegas 

• Resort Corridor 

• Other areas characterized by urban density and land use, and 

• Suburban areas. 

The free-flow speeds and capacities are set to default values in look up tables for each 

facility type and area type. The values for free-flow speeds are set out in Table 6 and 

capacities in Table 7. 

 Table 6. Free-Flow Speeds 

Free-Flow Speeds by Area Type 

Functional Class CBD Resort Urban Suburban 

System Ramps 40 40 51 53 

Minor Arterials 31 31 36 41 

Major Arterials 31 33 39 43 

Ramps 15 25 28 36 

Interstates 53 53 56 60 

Freeways 51 51 54 59 

Expressways 50 50 50 50 

Collectors 29 29 33 39 

Other 25 25 25 25 

HOV 55 55 60 65 

 Source: Regional Transportation Commission, Travel Demand Model, 2004 Pack 2A 

 

The speed-capacity equation coefficients were developed as a part of the model 

calibration process and reflect the observed characteristics of different types of roadway 

in the area. They are used in the assignment process to control the relationship 

between traffic flow, capacity and congested time.
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 17 

 Table 7. Free-Flow Capacities

Free-Flow Capacity by Area Type

Functional Class CBD Resort Urban Suburban 

System Ramps 2,000 2,000 2,000 2,000 

Minor Arterials 560 600 600 640 

Major Arterials 700 750 750 800 

Ramps 1,600 1,600 1,600 1,600 

Interstates 2,000 2,000 2,000 2,000 

Freeways 2,000 2,000 2,000 2,000 

Expressways 925 925 925 925 

Collectors 420 450 450 480 

Other 416 416 416 416 

HOV 1,950 1,950 1,950 1,950 

 Source: Regional Transportation Commission, Travel Demand Model, 2004 Pack 2A 

4.3. Horizon Year Networks 

The development of the future year networks begins with the identification and selection 

of “regionally significant” capacity-adding transportation projects that are proposed for 

inclusion in the RTP and TIP. The definition of regional significance is that contained in 

Section 2.2 of the RTCs “Policies and Procedures”, as amplified through the 

inter-agency consultative procedures laid down in the “Transportation Conformity Plan 

for the Las Vegas Valley Nonattainment Area”, Clark County Board of Commissioners, 

March 2005, and in 40 CFR 93 S.93.101. All such projects are included in the future 

build networks, irrespective of funding source. 

Projects are categorized by anticipated horizon year of completion, i.e., 2013, 2020 or 

2030. Alignments, design scope and attributes for new roads, and changes in the 

attributes of existing roads, are defined by NDOT and the local entities as part of the 

TIP process. Projects included in the model analysis are listed in Appendix I Capital 

Program Projects. 

Table 8 summarizes the contents of the 2013 No build year model networks and future 

build networks. In total, the 2013 No build coded model network covers approximately 

3638 link miles of roadway within the valley, as well as links representing the minor 

roads that connect zone centroids to the network, and roads leading into and out of the 

region. The 2030 build network has 3,945 link miles and 11,922 lane miles coded in the 

network. Table 9 shows the link miles and lane miles changes from the previous build 

horizon year due to the projects included in the next build horizon year. Note that the 

changes to centroid connector links are set to zero, because these changes are not 

necessarily caused by the projects, but by the reconfiguration, for coding purposes only, 

of the zone connections to the future projects. Table 10 shows that all projects 

included in this RTP will result in 530 more link miles and 2,570 more lane miles for the 

Valley from year 2013 to year 2030. 
 18 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 8. Network Link Miles and Lane Miles by Roadway Type 

2013 No Build 2013 Build 2020 Build 2030 Build

Description

Link 

Miles

Lane 

Miles

Link 

Miles

Lane 

Miles

Link 

Miles

Lane 

Miles

Link 

Miles

Lane 

Miles

External Links 43.11 93.67 43.11 93.67 43.11 93.67 43.11 102.64

System to System Ramp 28.83 37.91 28.55 37.63 31.32 43.57 37.39 55.65

Minor Arterial 413.62 1,737.96 421.12 1,753.08 478.42 2,091.38 565.19 2,495.08

Major Arterial 465.14 2,271.36 466.56 2,285.55 512.23 2,579.74 549.59 2,775.17

Ramp 141.79 181.35 143.54 183.39 145.94 186.32 157.71 204.98

Interstate 205.49 623.21 205.49 622.91 205.52 643.43 205.52 779.89

Freeway 124.38 377.80 124.38 377.80 126.11 403.91 138.12 447.99

Expressway/Beltway 0.81 1.90 0.81 1.90 19.78 77.68 19.78 77.68

Collector 690.60 1,886.56 690.60 1,886.56 676.18 1,900.94 745.77 2,097.12

Centroid Connector 1,455.45 2,910.90 1,455.45 2,910.90 1,341.15 2,682.30 1,334.02 2,668.04

Local 21.80 49.86 21.80 49.86 21.80 49.86 27.59 61.44

HOV Lanes 20.89 20.89 20.89 20.89 28.53 28.53 95.93 106.35

Transit Link 18.75 37.34 18.75 37.34 18.75 37.34 18.75 37.34

Transit Access Link 5.93 11.86 5.93 11.86 6.07 12.14 6.07 12.14

TOTAL 3,637 10,243 3,647 10,273 3,655 10,831 3,945 11,922

Source: Regional Transportation Commission staff

Table 9. Changes in Link Miles and Lane Miles over the Previous Horizon Year 

 2013 No Build 2013 Build 2020 Build 2030 Build 

Description 

Link 

Miles 

Lane 

Miles 

Link 

Miles

Lane 

Miles

Link 

Miles

Lane 

Miles

Link 

Miles 

Lane 

Miles

External Links 0.00 2.86 0.00 0.00 0.00 0 0.00 8.97

System to System 

Ramp 10.64 12.89 -0.28 -0.28 2.77 5.94 6.07 12.08

Minor Arterial 51.37 303.61 7.50 15.12 57.30 338.3 86.77 403.70

Major Arterial 14.77 158.95 1.42 14.19 45.67 294.19 37.36 195.43

Ramp 10.00 17.99 1.75 2.04 2.40 2.93 11.77 18.66

Interstate -0.07 71.14 0.00 -0.31 0.03 20.525 0.00 136.46

Freeway 9.81 65.96 0.00 0.00 1.73 26.11 12.01 44.08

Expressway/Beltway 0.00 0.00 0.00 0.00 18.97 75.78 0.00 0.00

Collector -23.57 -25.48 0.00 0.00 -14.42 14.38 69.59 196.18

Centroid Connector 0.00 0 0.00 0.00 0.00 0 0.00 0.00

Local 0.88 1.76 0.00 0.00 0.00 0 5.79 11.58

HOV Lanes 14.36 14.36 0.00 0.00 7.64 7.64 67.40 77.82

Transit Link 10.01 19.98 0.00 0.00 0.00 0 0.00 0.00

Transit Access Link 2.31 4.62 0.00 0.00 0.14 0.28 0.00 0.00

TOTAL 101 649 10 31 122 786 297 1,105

Source: Regional Transportation Commission staff
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 19 

Table 10. Total Changes in Link Miles and Lane Miles from 2008 Network to 2030 Build 

Total Changes from2008 to 2030

Description

Link 

Miles

Lane 

Miles

External Links 0.00 11.83

System to System Ramp 19.20 30.63

Minor Arterial 202.94 1060.73

Major Arterial 99.22 662.76

Ramp 25.92 41.62

Interstate -0.04 227.82

Freeway 23.55 136.15

Expressway/Beltway 18.97 75.78

Collector 31.60 185.08

Centroid Connector 0.00 0.00

Local 6.67 13.34

HOV Lanes 89.40 99.82

Transit Link 10.01 19.98

Transit Access Link 2.45 4.90

TOTAL 530 2,570

Sources: Regional Transportation Commission staff. 

4.4. No-Build Versus Build Year Networks 

As stated above, currently there is no approved Ozone (O3) mobile source emission 

budget or SIP, therefore the RTC has to conduct "Action versus No-Build Test” ( known 

also as Build Versus No-Build Test) for defining conformity for Ozone pollutant. The NoBuild network is determined by taking out all projects to be financed by the Federal 

funding from the Build network for the horizon year. 

Tables 11 to 13 list all Federal funded projects included in the Build networks but not in 

the No Build networks for the same horizon years. 

Figure 3.presents a map that shows the coded road network and all Federal funded 

projects not in the Build but in the No-Build networks. The projects are colored for 

different horizon years. 

Table 11. Federal Funded Projects in 2013 Build But Not in 2013 No-Build (No 

Action) 

ProjNo Sponsor Location From To Description

108 Clark 

County

Cactus Ave. @ 

I-15 a new interchange @ I-15

843 Henderson SR564 Lake 

Mead Pkwy Boulder Hwy

Lake Mead 

National 

Recreation 

Area

Widen to 6 lanes and a grade sepaerated 

intersection at Lake Las Vegas Entrance 

enhancements

4150 DNOT I-15 S. SR 160 (Blue 

Diammond) Tropicana Av. Widen from 6 to 8 lanes, include HOV and auxiliary lanes 

Source: Regional Transportation Commission staff 
 20 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 12. Federal Funded Projects in 2020 Build But Not in 2020 No-Build (No 

Action) 

ProjNo Sponsor Location From To Description

110 Henderson I-15 @ Starr Construct Interchange

244 NDOT I-15 South 

Phase 4 Sloan Rd SR 160 (Blue Diamond) 

I-15 South Phase 2: widen from 6 to 8 

lanes and add additional auxiliary lanes

894 Las Vegas Summerlin 

Pkwy. Beltway US 95 Widen to 8 lanes

4021 DoA Ivanpah 

Expressway

Ivanpah Valley 

Airport I-15 New Alignment (Ivanpah Expressway)

4146 North Las 

Vegas

Lake Mead 

Blvd. Losee Rd Las Vegas Blvd. 

Realign roadway and widen to 8 lanes, 

including dedicated right- and left-turn 

lanes, auxiliary lanes, and modification of 

freeway ramps associated with the I-15 

interchange. (PE, ROW, Construction

4149 NDOT

I-15 / US 95 

(Spaghatti 

Bowl) Neon 

Phase 1

 Construct a 4 lane system to system 

direct connect HOV ramps, including 

add/drop lanes at Oakey/Wyoming. Widen 

1-15 to accommodate HOV ramps 

(PE,RW, Const.)

4242 Las Vegas Elkhorn @US 95 Construct HOV direct connect

4249 Las Vegas Oakey / 

Wyoming I-15 Mains Street Construct a grade separation at Oakey/Wyoming

Source: Regional Transportation Commission staff 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 21 

Table 13. Federal Funded Projects in 2030 Build But Not in 2030 No-Build (No Action)

ProjNo Sponsor Location From To Description

115 Henderson I-15 @Bermuda Rd Construct an interchange (PE, ROW, 

Const)

243 NDOT I-15 South CA State Line Sloan Rd Widen from 6 to 8 lanes (PE, ROW, 

Const)

245 NDOT I-15 (Phase 4) Sloan Rd SR 160 Blue 

Diamond Rd 

I-15 South Phase 4: Widen to 10 lanes 

and add additional auxiliary lanes

247 NDOT I-15 (Phase 3) SR 160 (Blue 

Diammond Rd) Tropicana Ave

I-15 South Phase 3: Widen to 10 lanes 

and additional auxiliary lanes and 

operational improvements (PE, ROW, 

Const)

249 NDOT I-515 (Phase 2) Foothills Grade 

Separation

Charlestion 

Blvd

Widen to 10 lanes; to include HOV lanes 

and add new interchange @ Sahara Ave. 

(PE, ROW, Const)

250 NDOT I-515/US 95 

(Phase 1)

Charleston 

Blvd

I-15/US 95 

Interchange 

(Spaghetti 

Bowl)

Widen to 10 lanes; to include HOV lanes 

and add new interchange @ Pecos Rd, F 

St, (PE, ROW, Const)

758 Henderson I-15 @Sloan Construct an interchange (PE, ROW, 

Const)

823 North Las 

Vegas I-15 @Washburn 

Rd

Widen from 2 to 4 lanes and construct 

grade separation over I-15 on Washburn 

Rd. from Pecos Rd to Lamb Blvd

889 Las Vegas Sheep 

Mountain Pkwy

@US95 & 

CC215 

Western 

Beltway

Construct system to system interchange

4144 NDOT I-15 I-215

I-15/US 95 

(Spaghetti 

Bowl)

Widen from 10 to 14 lanes to include HOV 

lanes (PE, ROW, Const)

4147 NDOT

Martin L King 

Blvd/Industrial 

Rd Connector 

Neo

Palomino Ln Wyoming

Construct a 6-lane overpass with grade 

separation at Oakey/Wyoming (PE, ROW, 

Const)

4148 NDOT US 95 North 

(Package 2) Ann Rd Kyle Canyon 

Rd

Ann to Centennial: widen from 6 to 8 

lanes. Add auxiliary lanes.

Centennial to Durango: widen from 4 to 8 

lanes.

Durango to Kyle Canyon: widen from 4 to 

6 lanes. (PE, ROW, Const)

4153 NDOT I-15

@I-215 

Southern 

Beltway 

(Interchange)

System to system direct connector HOV 

ramps (PE, ROW, Const)

4161 NDOT

I-15 

Southbound 

NEON Phase 3

US 95 Sahara Ave

Construct SB collector distributor roads 

with new bridges over Alta, Charleston, 

and Oakey/Wyoming (PE, ROW, Const)

4162 NDOT

I-15 

Northbound 

NEON Phase 4

US 95 Sahara Ave

Construct SB collector distributor roads 

with new bridges over Sahara Ave., 

Oakey/Wyoming. Charleston and 

northbound off ramps to Alta Dr. (PE, 

ROW, Const)

4167 NDOT

SR 160 (Blue 

Diamond Rd) 

@ I-15

Construct a flyover ramp from EB SR 160 

to NB I-15 (PE, ROW, Const)

4247 Clark 

County Tropicana Ave Decatur Blvd Polaris Construct a grade seperation over Dean 

Martin Drive (PE, ROW, Const)

4248 Clark 

County Tropicana Ave Polaris I-15

Construct a fourth westbound lane 

(including replacement of the UPRR 

Bridge over Tropicana

Source: Regional Transportation Commission staff 
 22 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Figure 3. Federal Funded Projects Included in the Build But Not In NO-Build 

Horizon Years 

Sources: Regional Transportation Commission, Planning 

4.5. Transit Network, HOV and Park-and-Ride 

For the first time, and from this RTP, transit network skims, mode choice and transit 

assignments are modeled for the Las Vegas Valley. In addition, High Occupancy 

Vehicle (HOV) and Park –and Ride (PnR) facilities are also coded in the network, and 

the HOV and PnR trips can be modeled too. 

Figure 4. presents a map showing the 2030 Build transit network routes and the 

proposed future Park and Ride facilities. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 23 

Figure 4. 2030 Build Transit Routes and Future Park and Ride Facilities 

(All transit routes = Green; All future Park and Ride Facilities = Red Dots) 
 24 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

5. Travel Demand Model Result and Regional Travel 

The RTC Travel Demand Model Package 2A, a full four step travel demand model with 

visitor model elements is used to develop the following model results. A full description 

of the each step of the RTC Travel Demand Model is contained in Appendix II B Travel 

Demand Model Documentation, Regional Transportation Plan FY 2006-2030 October 

2006, by Regional Transportation Commission. The model’s new capabilities included 

in Pack 2A, such as Transit Processing, Mode Choice Modeling, HOV and Transit 

Assignment Capabilities are described at the end of this document. 

This section summarizes the modeling results from the each step of the RTC Travel 

Demand Model Pack 2A. 

5.1. Trip generation 

Trip Generation is the process of generating estimates of the person trips produced in, 

or attracted to, each zone. Table 14 summarizes the total number of person trips 

generated by the trip generation step of the travel demand model. 

Table 14. Person-Trips in the Las Vegas Valley, 2013-2030 

2013 2020 2030

Home-Based Work 1,341,000 1,631,301 1,901,401

Home-Based School 624,633 738,044 860,949

Home-Based Shopping 747,698 880,765 1,019,160

Other Home-Based 3,152,269 3,696,292 4,246,291

Non-Home-Based 2,397,000 2,837,200 3,278,900

Residence Air 18,066 21,577 18,066

Total Resident Trips 8,280,666 9,805,179 11,324,767

Multi-Day Visitor Trips 645,982 758,839 809,912

Visitor Airport Based Trips 142,011 170,180 193,164

Total Visitor Trips 787,993 929,019 1,003,076

Total Person Trips 9,068,659 10,734,198 12,327,843

Trip Purpose

Average Weekday Person Trips

 Source: Regional Transportation Commission staff 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 25 

Figure 5. Average Weekday Person Trips by Purpose 

(Series 1=2013, Series 2=2020, Series 3=2030) 

Average Weekday Person Trips by Purpose

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Home-Based Work

Home-Based School

Home-Based Shopping

Other Home-Based

Non-Home-Based

Residence Air

Total Resident Trips

Multi-Day Visitor Trips

Visitor Airport Based Trips

Total Visitor Trips

Total Person Trips

Trip Purpose

Trips in Thousand

Series1

Series2

Series3

 Source: Regional Transportation Commission staff 

5.2. Trip Distribution 

The RTC model distributes trips using a conventional gravity distribution algorithm. In 

this, zonal trip productions for each purpose are matched with trip attractions based on 

a computed probability function employing the travel time between zones. One of the 

key elements in this process are the estimation of travel times using the model network. 

Tables 15A through 15C below present the summaries of the average travel distance 

and average travel time by trip purpose and the total trips in the trip distribution model 

runs. Table 15D shows that from 2013 to 2030, with more trips and more congestions 

in the future, both the average travel distance and average travel time for most trip type 

increase. The average distance and average time for airport trips, including visitor 

airport and residence airport trips, increase due to the opening of Ivanpah Airport in 

2017, resulting in an increasing share of aviation demand being met by the Ivanpah 

Airport. 
 26 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 15A. 2013 Trip Distribution Summary

Average Total Trips within the TAZ

Trip Purpose Distance Time Trips Trips Percent

Home-Based Work Income Group 1 10.5 22.1 112,983 396 0.4%

Home-Based Work Income Group 2 10.1 21.8 126,699 211 0.2%

Home-Based Work Income Group 3 11.0 23.1 326,583 621 0.2%

Home-Based Work Income Group 4 12.1 24.5 774,735 882 0.1%

Home-Based School 4.5 11.8 624,633 34,010 5.4%

Home-Based Shopping 5.1 13.1 747,698 19,770 2.6%

Home-Based Other 7.3 17.1 3,152,269 34,856 1.1%

Non-Home-Based 7.0 16.4 2,397,000 82,073 3.4%

Hotel-Based Convention 3.8 13.4 56,493 973 1.7%

Hotel-Based Business 6.7 17.9 17,174 80 0.5%

Hotel-Based Gaming 4.2 14.0 175,199 2,747 1.6%

Visitor Hotel-Based Other 4.4 14.2 184,476 2,786 1.5%

Visitor Non-Hotel-Based Other 3.8 13.1 76,359 2,128 2.8%

Non-Hotel Gaming 3.8 13.3 133,747 3,520 2.6%

Visitor Airport 6.9 27.1 136,560 67 0.0%

Resident Airport 13.3 32.8 18,066 0 0.0%

Airport-Based Business 4.4 24.3 4,368 0 0.0%

Airport-Based Other 6.9 27.1 1,083 1 0.0%

Non-Airport-Based Business 6.3 16.2 1,661 28 1.7%

Non-Airport-Based Other 4.2 13.8 873 20 2.3%

Total Trips 9,068,659 185,167

Source: Regional Transportation Commission staff 

Table 15B. 2020 Trip Distribution Summary 

Average Total Trips within the TAZ

Trip Purpose Distance Time Trips Trips Percent

Home-Based Work Income Group 1 12.8 25.9 150,061 450 0.3%

Home-Based Work Income Group 2 10.3 23.1 154,663 263 0.2%

Home-Based Work Income Group 3 11.4 24.7 391,332 693 0.2%

Home-Based Work Income Group 4 12.4 26.0 935,245 1,095 0.1%

Home-Based School 4.8 12.6 738,044 31,102 4.2%

Home-Based Shopping 5.0 13.4 880,765 19,045 2.2%

Home-Based Other 7.3 17.7 3,696,292 45,380 1.2%

Non-Home-Based 7.8 18.3 2,837,200 74,535 2.6%

Hotel-Based Convention 3.7 13.7 65,893 1,202 1.8%

Hotel-Based Business 6.9 19.1 20,028 79 0.4%

Hotel-Based Gaming 4.0 14.4 206,167 3,853 1.9%

Visitor Hotel-Based Other 4.2 14.6 216,688 3,853 1.8%

Visitor Non-Hotel-Based Other 3.6 13.4 89,312 3,147 3.5%

Non-Hotel Gaming 3.7 13.6 158,219 4,801 3.0%

Visitor Airport 14.5 54.1 164,729 69 0.0%

Resident Airport 21.7 61.3 21,577 0 0.0%

Airport-Based Business 13.7 53.8 4,368 0 0.0%

Airport-Based Other 14.7 54.3 1,083 0 0.0%

Non-Airport-Based Business 6.2 16.5 1,661 33 2.0%

Non-Airport-Based Other 4.0 14.0 873 24 2.7%

Total Trips 10,734,198 189,624

Source: Regional Transportation Commission staff 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 27 

 Table 15C. 2030 Trip Distribution Summary 

Average Total Trips within the TAZ

Trip Purpose Distance Time Trips Trips Percent

Home-Based Work Income Group 1 15.3 29.6 203,847 388 0.2%

Home-Based Work Income Group 2 10.7 24.1 175,748 285 0.2%

Home-Based Work Income Group 3 11.9 25.7 447,293 773 0.2%

Home-Based Work Income Group 4 13.0 26.9 1,074,513 1,232 0.1%

Home-Based School 4.7 12.3 860,949 32,937 3.8%

Home-Based Shopping 5.2 13.5 1,019,160 20,924 2.1%

Home-Based Other 7.7 18.2 4,246,291 51,434 1.2%

Non-Home-Based 8.3 19.9 3,278,900 90,111 2.7%

Hotel-Based Convention 3.6 13.7 69,863 1,324 1.9%

Hotel-Based Business 7.1 19.5 21,227 70 0.3%

Hotel-Based Gaming 4.0 14.4 220,346 4,000 1.8%

Visitor Hotel-Based Other 4.2 14.7 231,161 4,000 1.7%

Visitor Non-Hotel-Based Other 3.6 13.5 94,936 3,555 3.7%

Non-Hotel Gaming 3.7 13.8 169,845 5,525 3.3%

Visitor Airport 15.9 79.0 187,712 72 0.0%

Resident Airport 23.1 86.8 23,747 0 0.0%

Airport-Based Business 14.8 78.2 4,368 0 0.0%

Airport-Based Other 15.9 79.0 1,083 0 0.0%

Non-Airport-Based Business 6.4 16.7 1,661 32 1.9%

Non-Airport-Based Other 4.0 14.2 873 26 3.0%

Total Trips 12,333,524 216,687

Source: Regional Transportation Commission staff 

Table 15D. Difference Trip Distribution Summaries Between 2013 and 2030 

Average Total Trips within the TAZ

Trip Purpose Distance Time Trips Trips Percent

Home-Based Work Income Group 1 4.8 7.4 90,864 -8 -0.2%

Home-Based Work Income Group 2 0.7 2.3 49,049 74 0.0%

Home-Based Work Income Group 3 0.9 2.6 120,710 152 0.0%

Home-Based Work Income Group 4 0.9 2.5 299,778 350 0.0%

Home-Based School 0.2 0.5 236,316 -1,073 -1.6%

Home-Based Shopping 0.1 0.4 271,462 1,154 -0.6%

Home-Based Other 0.4 1.0 1,094,022 16,578 0.1%

Non-Home-Based 1.3 3.5 881,900 8,038 -0.7%

Hotel-Based Convention -0.2 0.3 13,370 350 0.2%

Hotel-Based Business 0.4 1.6 4,053 -10 -0.1%

Hotel-Based Gaming -0.2 0.4 45,147 1,252 0.2%

Visitor Hotel-Based Other -0.2 0.5 46,685 1,213 0.2%

Visitor Non-Hotel-Based Other -0.2 0.4 18,577 1,428 1.0%

Non-Hotel Gaming -0.1 0.5 36,098 2,004 0.6%

Visitor Airport 9.0 51.9 51,152 5 0.0%

Resident Airport 9.8 54.1 5,681 0 0.0%

Airport-Based Business 10.4 53.8 0 0 0.0%

Airport-Based Other 9.0 51.9 0 0 0.0%

Non-Airport-Based Business 0.1 0.5 0 5 0.3%

Non-Airport-Based Other -0.2 0.4 0 7 0.7%

Total Trips 3,264,865 31,520

Source: Regional Transportation Commission staff 
Regional Transportation Plan FY 2005-2030 Appendix 4 Page 28 

5.3. Mode Choice 

The RTC 2004 Model Pack 2 includes additional and optional transit processing and 

mode Choice modeling capabilities. The basic procedures include in the RTC 2004 

Model Pack 2 are Transit network coding procedures; Transit path-building and 

skimming procedures; Mode choice procedures; Transit assignment procedures; and 

HOV modeling procedures. These added procedures greatly enhance the transit 

forecast and analysis capabilities of the RTC model. It is the first time that the RTC 

model is able to forecast the transit ridership and HOV volumes for the future horizon 

years. The model choice uses a nested logit model to estimate the zone-to-zone person 

trips that travel in autos and that use transit services. Table 16 shows a summary of 

total person trips by model as the results of the mode choice model. 

Table 16. DAILY - TOTAL PERSON TRIPS BY MODE (including visitor trips) 

Description 2013 2020 2030 % Change 

2013-2030

TOTAL DAILY PERSON - DRIVE-ALONE 3,979,728 4,705,216 5,418,704 36.2%

TOTAL DAILY PERSON - SHARED RIDE 4,363,426 5,182,533 6,025,382 38.1%

TOTAL DAILY PERSON - DRIVE - TRANSIT 2,698 9,003 15,120 460.4%

TOTAL DAILY PERSON - LOCAL - TRANSIT 180,833 196,565 198,073 9.5%

TOTAL DAILY PERSON - PREMIUM - TRANSIT 38,641 62,139 64,081 65.8%

TOTAL DAILY PERSON - TAXI 183,640 199,141 206,364 12.4%

TOTAL DAILY PERSON - TOUR_SHUTTLEBUS 45,070 45,923 47,021 4.3%

TOTAL DAILY PERSON - OTHER - WALK 274,623 333,680 358,779 30.6%

DAILY_TOTAL PERSON - VEHCILE 6,235,281 7,355,511 8,464,294 35.7%

DAILY_TOTAL PERSON - TRANSIT 222,172 267,706 277,274 24.8%

Source: Regional Transportation Commission staff 

A. Auto Trips 

The person trips traveling in autos are then turned into an estimate of auto trips through 

the application of vehicle occupancy rates derived from an earlier household survey. 

The rates set out in Table 17 are held constant for all forecast horizon years. Note that 

the term “auto” in this context includes light trucks and vans used for personal travel as 

well as passenger cars. 

 Table 17. Vehicle Occupancy Rates 

Travel Purpose 

Average Vehicle Occupancy 

(Persons per Vehicle) 

Home-Based Work 1.06 

Home-Based School 1.23 

Home-Based Shopping 1.43 

Other Home-Based 1.70 

Non-Home-Based 1.53 

Overall Average 1.39 

 Source: Regional Transportation Commission, Travel Demand Model, 2004 Pack 2A. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 29 

The Vehicle Occupancy Rates are used to convert person travel trips made entirely 

inside the region into vehicle trips. Vehicle trips not included are ones into and out of 

the region and through trips that cross the region. Projections of total vehicle travel 

include these and commercial trips made by trucks, buses.

The model network includes ten cordon stations on roads crossing the regional 

boundary which are connected to the rest of the network by external connector links. 

Projections of external trips and the distribution of the local end of those trips have been 

developed jointly with NDOT through the inter-agency consultative process. 

Commercial vehicle trips, including light delivery and service trips as well as truck trips, 

are separately forecasted and distributed. These projections are added to the number 

of auto trips to give total vehicle trips summarized in Table 13. Figure 4.5 shows the 

percentage changes in trips by vehicle type from 2013 to 2030. The higher percentage 

changes in external trips reflect all fast growths surrounding the modeling area, 

including areas outside Clark County, and adjacent states. 

Table 18. Vehicle Trips in the Las Vegas Valley, 2013-2030 

Average Weekday Vehicle Trips % Changes 

2013 2020 2030 2013- 2030

Drive Alone 4,334,553 5,126,732 5,908,730 36.3%

Shared Drive 1,900,728 2,228,779 2,555,564 34.5%

Auto Trips 6,235,281 7,355,511 8,464,294 35.7%

External Trips 133,689 159,334 195,685 46.4%

Truck Trips 221,136 262,182 294,340 33.1%

Taxi Trips 177,153 187,399 191,742 8.2%

Total Vehicle Trips 6,767,259 7,964,427 9,146,062 35.2%

Trip Purpose

Source: Regional Transportation Commission, Travel Demand Model, 2004 Pack 2A. 

Figure 6. Percent Changes in Vehicle Trips by Type from 2013 to 2030 

Percent Changes in Vehicle Trips from 2013 to 2030

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

Drive

Alone

Shared

Drive

Auto

Trips

External

Trips

Truck

Trips

Taxi Trips Total

Vehicle

Trips

Vehicle Trip Type

Percent Increase

% Changes 

2013- 2030

Source: Regional Transportation Commission staff 
 30 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

5.4. Assignments 

A. Time-of-Day Auto Trip Analysis 

Before the estimates of average daily vehicle trips for each trip purpose are 

assigned to the road links of the networks, these vehicle trips are grouped into seven 

time periods. These periods were defined through the inter-agency consultative 

process and are based on the observed distribution of traffic flow as shown by 

continuous traffic counts. The periods are: 

• From midnight to 7 a.m. (7 hours), 

• From 7 to 9 a.m. (2 hours), 

• From 9 a.m. to 2 p.m. (5 hours), 

• From 2 to 4 p.m. (2 hours), 

• From 4 to 6 p.m. (2 hours), 

• From 6 to 8 p.m. (2 hours) and 

• From 8 p.m. to midnight (4 hours). 

The vehicle trips for each travel purpose are grouped according to the proportion of 

daily trips that start or return in each time period. Then an equilibrium highway 

assignment process is used to load the time of day zone-to-zone vehicle trips onto the 

road network. The trips are assigned to road links based on computed travel times that 

take into account the relationships among traffic flow, free-flow speed, roadway capacity 

and congested (or “loaded”) speed and travel time. The formula used is a modification 

of the Bureau of Public Roads (BPR) formula for computing the decrease in speed as 

roads approach congested volumes. The coefficients in the formula have been 

developed from the Highway Capacity Manual and modified through the model 

calibration process to reflect local conditions. 

The assignment is performed for each of the seven time periods. Results are then 

aggregated to produce daily traffic flows on each link in the network. The following 

tables present summaries of the unadjusted modeled forecasts for the Valley. It should 

be noted that the road types changes for some links in the future over years due to the 

projects to be built. The vehicle miles traveled (VMT) are calculated by the trips 

assigned to the model network links and the link lengths of the network. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 31 

Table 19A. 2013 Trip Assignment Summary 

Road Type Daily VMT Daily Flow Average Daily Speed

External Links 267,023 151,688 25.0

System to System Ramps 429,929 2,051,297 43.2

Minor Roads 5,789,031 31,420,075 31.9

Major Roads 16,091,321 92,805,264 32.7

Ramps 1,289,615 7,785,191 26.5

Interstates 11,103,747 28,240,866 48.1

Freeways 5,072,947 18,441,884 50.7

Expressways 442 3,482 50.0

Collectors 3,279,469 15,261,459 30.4

Centroid Connectors 3,536,622 12,022,323 25.0

Local Roads 52,935 343,230 28.4

High Occupancy Vehicle (HOV) 270,241 1,342,648 51.4

Total 46,913,082 208,526,762

Source: Regional Transportation Commission 

Table 19B. 2020Trip Assignment Summary 

Road Type Daily VMT Daily Flow Average Daily Speed

External Links 316,079 180,649 25.0

System to System Ramps 490,081 2,298,662 41.9

Minor Roads 7,941,243 41,314,145 31.4

Major Roads 18,789,717 106,121,042 31.6

Ramps 1,543,606 9,492,261 26.7

Interstates 14,566,624 38,071,585 45.5

Freeways 6,857,699 23,022,393 49.7

Expressways 1,062 8,979 49.7

Collectors 3,735,466 17,050,606 29.8

Centroid Connectors 4,355,423 14,232,600 25.0

Local Roads 60,318 382,196 27.7

High Occupancy Vehicle (HOV) 358,128 1,723,573 49.8

Total 58,657,318 252,175,117 Source: Regional Transportation Commission 

Table 19C. 2030 Trip Assignment Summary 

Road Type Daily VMT Daily Flow Average Daily Speed

External Links 392,087 221,999 25.0

System to System Ramps 665,298 4,069,275 40.6

Minor Roads 9,415,217 47,709,671 31.8

Major Roads 20,600,457 114,260,574 31.3

Ramps 1,726,555 10,842,809 26.8

Interstates 18,047,187 48,133,295 45.8

Freeways 8,128,180 26,901,345 49.0

Expressways 863,808 230,357 21.6

Collectors 4,465,254 18,847,960 30.0

Centroid Connectors 4,844,743 16,367,002 25.0

Local Roads 89,631 455,483 27.0

High Occupancy Vehicle (HOV) 1,667,233 4,620,960 44.5

Total 69,238,417 288,039,769 Source: Regional Transportation Commission 
 32 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 19D. Changes in Trips Assignments from 2013 to 2030 

Road Type

% Changes 

in Daily VMT

% Changes 

in Daily Flow

Changes in Average 

Daily Speed

External Links 46.8% 46.4% 0.0

System to System Ramps 54.7% 98.4% -2.6

Minor Roads 62.6% 51.8% -0.1

Major Roads 28.0% 23.1% -1.4

Ramps 33.9% 39.3% 0.3

Interstates 62.5% 70.4% -2.4

Freeways 60.2% 45.9% -1.7

Expressways 195428.8% 6515.3% -28.4

Collectors 36.2% 23.5% -0.4

Centroid Connectors 37.0% 36.1% 0.0

Local Roads 69.3% 32.7% -1.4

High Occupancy Vehicle (HOV) 516.9% 244.2% -6.9

Total 47.6% 38.1% Source: Regional Transportation Commission 

One element of travel not included in the network assignment. These are intra-zonal 

trips. The intra-zonal trips are computed by applying an intra-zonal trip length to the 

intra-zonal trips tabulated in the trip table but not assigned to the network. Since 

TRANSCAD does not have a procedure for calculating this length, a default length of 

one mile has been used, based on the fact that nearly all zones in the model are no 

more than one square mile in area. 

B. Transit Assignment Results 

The other element is transit vehicle trips that is included in the network modeling for this 

RTP and is summarized in Table 20. In the table, total modeled daily transit trips, total 

daily boarding, total Transit Person Miles Traveled (PMT) and Transit Person Hours 

Traveled (PHT) are summarized. Transit trips increase by over 20% in the year of 

2020 from the year of 2013, this changes are mainly caused by the proposed increase 

and the improvement in transit services for year 2020. The transit service supplies for 

year 2030 basically remain the same for the year of 2020, and the slight 4% increase in 

the transit trips will be due to the net increase from the regional growth. 

Table 20. Modeled Daily Transit Trips, Person Miles Traveled and Person Time Traveled. 

Year % Increase from 

Descriptions 2013 2020 2030 2013-2030

Total Transit Trips 222,172 267,706 277,274 24.8%

Person Miles Traveled (PMT) 1,199,032 1,554,870 1,680,600 40.2%

Person Hours Traveled (PHT) 139,271 167,737 175,920 26.3%

Total Daily Boarding 359,748 435,413 449,588 25.0%

% change in Transit Trips 20% 4%

% change in PMT 30% 8%

% change in PHT 20% 5%

% change in Daily Boarding 21% 3%

Source: Regional Transportation Commission 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 33 

Figure 7A. Modeled 2013 Horizon Year Auto Time From All TAZs to TAZ 528 

(County Building is located in TAZ 528) 

Figure 7B. Modeled 2030 Horizon Year Auto Time From All TAZs to TAZ 528 

(County Building is located in TAZ 528) 
 34 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Figure 8A. Modeled 2013 Horizon Year Auto Time From All TAZs to TAZ 687 (Las 

Vegas @ Flammingo) 

Figure 8B. Modeled 2030 Horizon Year Auto Time From All TAZs to TAZ 687 (Las 

Vegas @ Flammingo) 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 35 

Figure 9. 2008 (Top) and 2030 (Bottom) Modeled Daily Volumes 
 36 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Figure 10. 2008 (Top) and 2030 (Bottom) Modeled PM PK Congestions (V/C Ratio) 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 37 

5.5. Model Travel Forecast Corrections 

A series of corrections and adjustments are made to the modeled VMT before they are 

used as a basis for estimating mobile source emissions. 

The first set of adjustments involves comparing modeled volumes with traffic counts and 

correcting errors in assigned traffic volumes. NDOT and the local entities have an 

extensive program of traffic counts and over 1,000 count locations are coded into the 

Master Highway network. These counts are aggregated by roadway group. When this 

RTP analysis was performed, the updated NDOT traffic counts available were NDOT 

2007 traffic counts. In order to compare apples to apples, the model was run with 2007 

roadway network and the 2007 model input file, then assigned traffic volumes were 

compared with the NDOT 2007 traffic counts. The aggregate modeled volume at count 

locations in each facility type is compared with the corresponding counts to produce an 

overall percentage error for count locations in that facility type. This error is expressed 

as a correction factor that is then applied to the VMT for all links in that group. Table 21 

lists these comparisons and correction factors. 

Table 21. Correction to 2007 Year Ground Counts 

Facility Type 

Number 

of 

Count 

Stations 

Aggregate 

Model 

Flow 

Aggregate 

Count 

Flow 

Conversion 

Factor 

External Links 6 71,122 70,345 0.98908 

System Ramps 30 458,561 470,005 1.02496 

Minor Arterials 261 3,799,773 4,127,135 1.08615 

Major Arterials 425 14,441,395 13,190,104 0.91335 

Ramps 251 2,153,535 2,125,360 0.98692 

Interstates 122 8,899,227 8,090,475 0.90912 

Freeways 39 2,426,553 2,033,770 1.05241 

Expressways/Beltways 3 48,761 76,203 1.56279 

Collectors 247 1,438,071 1,589,457 1.10527 

Source: Regional Transportation Commission. 

Note that in Table 21, the direct initial correction factor for Freeways was 0.83813, 

which was recalculated to 1.05241. Because some existing Expressways/Beltways are 

re-classified as Freeways in the future horizon years (see Figure 11 that shows a 

roadway functional class for different horizon years), the initial and directly calculated 

conversion factor needs to be adjusted, such as follows: Freeway factor = (freeway 

counts + expressway counts)/(model freeway flows + model expressway flows)+ 0.2. 

See the map showing the functional class of the highways. This step results in link 

volumes and VMT that are corrected to observed volumes. 
 38 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Figure 11. Current and Future Roadway Functional Class 

In accordance with Federal guidance, this corrected model VMT is then benchmarked 

against the base year VMT from the Highway Performance Monitoring System (HPMS). 

At the time when this document is prepared, the most resent HPMS data is the total 

VMT by county in 2006 Annual Traffic Report published by Nevada Department of 

Transportation. 

The system-wide correction factor used to control the corrected model VMT to the 

HPMS total is calculated in the following steps. First, the NDOT HPMS (2006 Annual 

VMT (AVMT)) for the Clark County Urbanized Area is converted into Annual Average 

Weekday VMT (AAWDVMT); Second, the 2006 AAWDVMT was factored up to 2007 

AAWDVMT by an average growth rate in the HPMS from years of 2004 to 2006. The 

third step is to match the RTC modeling area to the NDOT defined Urbanized Area. 

See Figure 12 for the NDOT defined Urbanized Area. The RTC modeling area is 

basically the same as the 2004 NDOT defined Urbanized Area, except for the newly 

expanded modeling areas for Boulder City, Ivanpah Airport, and Apex Industrial areas. 

See Figure 13. The VMT on these roads was subtracted from the total modeled 

WDVMT. Then, for the same specified Urbanized Area, the 2007 AAWDVMT was 

compared with the corrected model WDVMT to develop an adjustment factor. This 

factor is applied to the entire system in the model to derive corrected and benchmarked 

base year VMT. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 39 

Figure 12. NDOT Defined Urbanized Area 
 40 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Figure 13. The Links (in Red) for which the VMT Was Subtracted From the Total 

Modeled VMT. 

The process is summarized as follows. 

• Year 2006 HPMS Annual VMT for the Urbanized Area: 12,701,427,381 

• Year 2006 HPMS Annual Average Weekday VMT for the Urbanized Area: 

34,798,431 

• Year 2007 HPMS Annual Average Weekday VMT for the Urbanized Area: 

37,024,418. 

• Year 2007 Model AAWDVMT for the Las Vegas Valley: 36,969,095 

• Year 2007 Model AAWDVMT link corrected to: 35,960,657 

• After Subtracted Model AAWDVMT outside Urban Area: 33,675,538. 

• Year 2007 HPMS correction factor: 1.099 

The correction and HPMS factor are applied to all future horizon years, so that the 

emissions for each year are calculated using the modeled growth in VMT based upon a 

corrected and HPMS adjusted 2007 base.
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 41 

5.6. Travel Forecast Seasonal Adjustments 

The corrected and HPMS adjusted AAWDVMT is then adjusted to reflect the winter and 

summer conditions that are characteristic of peak CO emissions and O3 emissions 

respectively. This involves two factors. The first is a seasonal adjustment from 

AAWDVMT to December average weekday VMT. 2004 NDOT continuous traffic counts 

are employed to calculate this factor (0.969). The summer seasonal adjustment factors 

are calculated using the average of June, July and August ADT. Table 22 shows the 

factors. There are no significant differences in seasonal traffic patterns across the 

various roadway functional classes, so the same factor is applied equally to all modeled 

VMT. The 2004 seasonal adjustment factor is also held constant for all future horizon 

years. 

Table 22. Seasonal Adjustment Factors 

Summer adjustment factor 1.021711371 

Winter adjustment factor 0.969123638 

Source: NDOT, Hourly Counts, 2004 RTP 2006-2030 

5.7. Vehicle Miles Traveled Outside Modeling Area But Inside Ozone Nonattainment Area 

A. Introduction 

The 8-hour Ozone Non-attainment Area is larger than Las Vegas Regional Travel 

Demand modeling domain. This section describes how the VMT is developed for the 

traffic outside the modeling boundary but within the Ozone Non-attainment Area. Two 

elements are involved in this development, one is the traffic on the corridors such as 

State Route or Interstate outside the modeling network but within the Ozone Nonattainment Area; the other element is traffics generated in small communities outside 

the modeling area but within the Ozone Non-attainment Area. The following will 

describe each of these separately. 

B. The VMT on the roadway corridors 

The VMT outside the modeling area are calculated using available NDOT traffic counts. 

First, the corridors inside the Ozone Non-attainment boundary but outside of the RTC 

TDF model boundary are identified. Table 23A presents a list of roadway corridors 

identified. This table includes corridor endpoints, length, total lanes, and posted speed. 

Note that due to the TAZ expansion in this RTP, the number of corridors or the lengths 

of some of the corridors have been updated (reduced) from the RTP 2006-2030. In 

Table 23A, the average speeds are listed, where the average speeds equals the posted 

speed if it is constant for the corridor, where the posted speed varies for a corridor, the 

speed monitoring data is not available, the average travel speeds have been estimated 

by the information from the NDOT’s Annual Speed Monitoring Report. This dataset 

assumes that the average travel speed will not change on a segment during the 2013 to 

2030 period. 
 42 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 23A. List of Roadway Corridors Outside Modeling Network 

Corridor Endpoints 

Length 

(mi) 

Lanes 

(both 

dir.) 

Posted 

Speed 

Average 

Speed 

I-15 North 

TDF Model Boundary and 

Moapa/Glendale 24 4 75 75 

US 95 South CA Stateline and US 93 Interchange 60 2 to 4 70 70 

US 93 North I-15 Interchange and Ozone Boundary 11 2 70 70 

US 93 South AZ Stateline and Boulder Beach 5 2 Varies 50 

US 93/95 

US 95/93 Interchange and TDF Model 

Boundary 2.5 4 65 65 

SR 160 

TDF Model Boundary and Ozone 

Boundary 12 2 70 70 

SR 159 SR 160 and TDF Model Boundary 14 2 Varies 55 

SR 157 

US 95 and end of road at Mt. 

Charleston 19 2 Varies 55 

SR 158 SR 157 and SR 156 7 2 Varies 45 

SR 156 

US 95 and end of road at Mt. 

Charleston 18 2 Varies 55 

SR 163 US 95 and AZ Stateline 26 2 to 4 Varies 55 

Casino Drive Needles Highway and SR 163 13 2 to 4 Varies 35 

Bruce Woodbury 

Drive Needles Highway and Casino Drive 8 2 Varies 40 

Davis Dam Road SR 163 and Davis Dam 7 2 Varies 45 

Needles Highway CA Stateline and SR 163 13 2 to 4 Varies 60 

SR 147 

TDF Model Boundary and Ozone 

Boundary 2 2 65 65 

SR 168 Ozone Boundary near Glendale 6 2 Varies 45 

Valley of Fire 

Road I-15 Interchange and Ozone Boundary 15 2 65 65 

SR 161 I-15 Interchange and Ozone Boundary 12 2 70 70 

SR 164 I-15 Interchange and Searchlight 20 2 70 70 

Source: Regional Transportation Commission staff 

Next, the future traffic volumes are projected for these corridors. Forecast for future 

AADTs are based on the data from two sources. The NDOT has projected the traffic 

volumes for the RTC modeling network external connectors (see Appendix B at the end 

of this document), Therefore the NDOT’s projections are used where the data is 

available. In Table 16B, the NDOT’s estimates are highlighted with yellow color. The 

traffic volume projects for the remaining corridors are developed by applying average 

annual growth from the historical NDOT’s traffic counts AADT at stations on these 

corridors. Table 23B also provides the estimated VMT that is calculated by multiplying 

the volume estimates and the corridor length. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 43 

Table 23B. Traffic Volume and VMT Estimates for the Outside Corridors 

Corridor 

2013 

Volume 

2020 

Volume 

2030 

Volume

2013 

VMT

2020 

VMT

2030 

VMT 

I-15 North 28,160 34,000 42,000 675,840 816,000 1,008,000 

US 95 South 14,800 19,000 24,000 888,000 1,140,000 1,440,000 

US 93 North 1,710 1,850 2,200 18,810 20,350 24,200 

US 93 South 19,200 22,000 25,000 96,000 110,000 125,000 

US 93/95 19,200 22,000 25,000 48,000 55,000 62,500 

SR 160 13,800 17,000 21,000 165,600 204,000 252,000 

SR 159 7,360 9,800 13,000 103,040 137,200 182,000 

SR 157 3,920 4,700 6,500 74,480 89,300 123,500 

SR 158 750 802 1,125 5,250 5,614 7,875 

SR 156 680 762 915 12,240 13,716 16,470 

SR 163 8,000 8,000 10,600 208,000 208,000 275,600 

Casino Drive 8,000 9,860 11,700 104,000 128,180 152,100 

Bruce 

Woodbury 

Drive 11,000 11,900 13,500 88,000 95,200 108,000 

Davis Dam 

Road 400 400 400 2,800 2,800 2,800 

Needles 

Highway 13,000 15,800 17,015 169,000 205,400 221,195 

SR 147 3,920 4,700 6,500 7,840 9,400 13,000 

SR 168 1,400 1,600 1,820 8,400 9,600 10,920 

Valley of Fire 

Road 760 870 1,060 11,400 13,050 15,900 

SR 161 3,200 3,640 4,470 38,400 43,680 53,640 

SR 164 1,100 1,300 1,560 22,000 26,000 31,200 

Source: Regional Transportation Commission 

C. The VMT on Minor Arterials, Collectors and Locals 

 In addition to the VMT and speed estimates for the roadways listed in the above two 

tables, estimates of VMT and speed were made for travel on minor arterials, collectors 

and local streets in the cities of Laughlin, Searchlight, Blue Diamond, Cal-Nev-Ari, and 

Goodsprings. Estimates were based on VMT per person. Using the same approach 

from the 2004 Urban Mobility Report (http://mobility.tamu.edu/ums) to assist in the 

development of VMT per person for the cities listed above. It was assumed that all 

travel on interstates, freeways, expressways, and major arterials was captured in the 

itemized estimates summarized in Table 16B. Therefore, the estimates summarized 

following only cover travel on roadways classified as minor arterials, collectors, and 

locals. Table 24A and 24B summarize the population forecasts and the VMT per capita 

estimates. 

According to Flexibility in Highway Design, Chapter 3, Functional Classification

(http://fhwa.dot.gov/environment/flex/ch03.htm), travel on minor arterials, collectors, and 
 44 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

local roads account for 46.7 percent of average daily travel on US roadways. These 

VMTs were then disaggregated to minor arterials, collectors, and locals using factors 

listed in Table 24C which were derived from Flexibility in Highway Design and the RTC 

TDF Model. The data in Table 24C was then used to develop the VMT by average 

speed values in Table 24D. 

Table 24A: Population Forecasts 

City 2006 2010 2015 2020 2025 2030 

Laughlin 8629 15084 25807 34295 50276 54773 

Searchlight 780 1459 1707 1987 1987 1987 

Blue Diamond 439 524 2129 3802 4070 5918 

Cal-Nev-Ari 248 316 316 350 350 350 

Goodsprings 257 257 296 476 476 476 

Source: Clark County Department of Comprehensive Planning and Regional Transportation Commission. 

(Year 2006 data came from CCDCP.) 

Table 24B: Estimate of VMT Per Capita 

 VMT City 

Per capita 2013 2020 2030 

Laughlin 5 100,234 160,660 252,750

Searchlight 2 2,740 3,288 3,324 

Blue Diamond 2 1,249 1,380 1,390 

Cal-Nev-Ari 2 597 648 650 

Goodsprings 2 561 956 966 

VMP Per Capita Index Source: Texas Transportation Institute, Urban Mobility Study 

Table 24C: Summary of Percent VMT and Average Speed for Minor Arterials, 

Collectors, and Local Roadways 

Roadway Type Percent VMT Speed (mph) 

Minor Arterial 39 35 

Collector 33 30 

Local 28 36 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 45 

Table 24D: Summary of Forecast VMT by Average Speed on Minor Arterials, 

Collectors, and Local Roadways

 VMT Place/Roadway Type 

2013 2020 2030 

Laughlin 

Minor Arterials (35 mph) 39,091 62,657 98,573

Collectors (30 mph) 33,077 53,018 83,408

Locals (25 mph) 28,066 44,985 70,770

Searchlight 

Minor Arterials (35 mph) 1,068 1,282 1,296

Collectors (30 mph) 904 1,085 1,097

Locals (25 mph) 767 921 931

Blue Diamond 

Minor Arterials (35 mph) 487 538 542

Collectors (30 mph) 412 455 459

Locals (25 mph) 350 386 389

Cal-Nev-Ari 

Minor Arterials (35 mph) 233 253 254

Collectors (30 mph) 197 214 215

Locals (25 mph) 167 181 182

Goodsprings 

Minor Arterials (35 mph) 219 373 377

Collectors (30 mph) 185 315 319

Locals (25 mph) 157 268 270

Total 

Minor Arterials (35 mph) 41,098 65,103 101,041

Collectors (30 mph) 34,776 55,088 85,496

Locals (25 mph) 29,507 46,741 72,542

Source: Regional Transportation Commission 

6. Carbon Monoxide Mobile Source Emissions Forecasts 

6.1. Introduction 

Mobile source emissions for CO are calculated by using emission factors developed 

through the Mobile6.2 emissions model. These emission factors are the average 

emissions per vehicle-mile for a particular speed of travel, as determined by the EPA. 

The settings used in the Mobile6.2 model were developed in cooperation with the Clark 

County Department of Air Quality Management, and are similar to those used in the 

development of the CO SIP. 

The Mobile6.2 model takes into consideration the effects of the different emissions from 

various vehicle types, such as passenger vehicle, light truck, heavy truck and 

motorcycle, as well as the effect of the mix of gasoline-powered and diesel-powered 

vehicles. 
 46 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Specific input settings define the following factors for each forecast horizon year: 

• Fleet mix composition, 

• Mileage accumulation rates by vehicle type and age, 

• Vehicle registration rates by vehicle type and age, 

• Impact of inspection/maintenance programs, 

• Impact of anti-tampering programs, 

• Impact of refueling controls, 

• Reid vapor pressure of fuel, 

• Daily minimum, maximum and ambient temperatures, 

• Oxygen content of fuel and 

• Vehicle speed. 

The basic calculation steps are: The link-specific emissions calculation is performed 

based on the procedure outlined in the 2005 CO SIP; Adjust the daily volumes to hourly 

volumes; Adjust the link speeds using the hourly volume to capacity ratio in the BPR 

curve; Calculate the hourly link VMT as the hourly volume times the link length; 

Calculate the link emissions as the link VMT times the MOBILE6.2 composite emission 

factor for the link roadway type, hour, and adjusted link speed; Adjust the emissions to 

average December day, by HPMS factor, count-to-model volume factor, growth factor 

and transit factor. The emissions for each facility type are then summed to give the 

modeled mobile source emissions for each year, as shown in Table 25. 

Table 25: 2010-2030 CO Emissions Summary 

 Total CO Emissions (tons/day) 

Facility Type 2007 2010 2013 2015 2020 2030 

External 2.15 2.08 2.01 2.01 2.01 2.35 

System-to-system Ramp 4.77 4.64 4.51 4.45 4.41 5.56 

Minor Arterial 45.03 47.25 49.47 52.78 57.75 65.02 

Major Arterial 122.77 118.89 115.00 114.15 113.59 118.28 

Ramp 14.34 13.68 13.02 13.17 13.40 13.89 

Interstate 92.26 88.96 85.65 89.77 95.96 114.16 

Freeway 37.72 41.35 44.99 47.85 52.14 59.51 

Expressway 5.62 2.81 0.01 0.01 0.01 9.76 

Collector 27.90 27.93 27.96 27.33 26.91 30.95 

Centroid 29.20 29.43 29.67 30.44 31.59 33.72 

Local 0.53 0.49 0.44 0.44 0.44 0.63 

HOV 0.00 0.95 1.90 2.00 2.16 9.30 

TOTAL 382 378 375 384 400 463 

Budgets 623 690 690 768 817 817 

Source: The budgets were from Clark County Carbon Monoxide Modeling and SIP, October, 2005, DAQEM, 

Emission Calculations are from the Regional Transportation Commission staff. 

The horizon analysis years for this RTP are 2013, 2020 and 2030. However, to meet 

the Transportation Conformity Rule, in addition to including the attainment year and the 

last year of the transportation plan, the analysis must include any years which the SIP 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 47 

establishes MVEB that are within the timeframe of the transportation plan. For CO, that 

means that the analysis years 2010 and 2015 must be included. Note that the 

emissions analysis, for comparison to the years when MVEBs are established, may be 

determined by interpolating between the years for which the full regional emissions 

analysis is performed. Therefore, if regional emissions were established by a full 

network run for 2013 and 2020, emissions for 2015 could be interpolated for 

comparison to the MVEB. In Table 25, the emissions for year 2010 were interpolated 

from the emissions between years 2007 and 2013, and the emissions for year 2015 

were interpolated from the emissions between years 2013 and 2020. 

Modeled mobile source CO emissions can be reduced through the application of credits 

for the various Transportation Control Measures as defined in the State Implementation 

Plan. The first of these measures - technician training - is related to the Vehicle 

Inspection and Maintenance Program, and the effect of this program is included in the 

emissions modeling process through the application of the relevant Mobile 6.2 input 

settings. The other TCM’s have the effect of reducing emissions below the level 

predicted through the modeling process. Based on the information supplied by the 

DAQEM, reduction factors are included in the CO input setup file for the Mobile 6.2 

modeling of the travel output from the RTC’ travel demand model. Table 26.shows that 

the net CO Emissions are the same as the Total emissions listed in Table 25. As the 

future CO Emissions are below the budgets with big margins, this analysis will not 

extend to extensive and detailed discussions about the control measures. 

Table 26. Net CO Emissions 

Emissions in Tons Per Day 

 2007 2010 2013* 2015 2020 2030 

Modeled CO Emissions 382 378 375 384 400 463 

TCM’s Credited in Model n/a n/a n/a n/a n/a n/a 

Net CO Emissions 382 378 375 384 400 463 

Source: Regional Transportation Commission staff 

7. PM10 Modeling Assumptions 

7.1. Transportation Activities Contribution to PM10 Emissions

According to the 2001 PM10 SIP, over 37 percent of the Las Vegas Valley’s dust 

emissions are related to transportation activities; 26 percent of the PM10 emissions are 

linked to travel on paved roads and 9 percent can be attributed to travel on unpaved 

roads. While the inventory process has correctly characterized the problem, it is 

beneficial to review the primary sources of PM10 to understand how control regulations 

for construction will reduce future emissions and help to demonstrate positive air quality 

conformity. 

The paved roadway network itself is not directly responsible for emissions. Rather, 

fugitive dust originating from construction activities and disturbed vacant land are the 

primary contributors. Wind and construction “track out” deposit dust on roads and the 
 48 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

movement of vehicles traveling over the pavement re-entrains the dust into the air, 

which contributes to the regional PM10 emission problem. Paved road emissions also 

include a category of streets where the paved surface does not exceed 28 feet in width 

and are classified as streets with “unpaved shoulders”. The idea is that, due to the 

narrow paved width, vehicles often travel onto the shoulders and track dust back onto 

the paved surface, contributing to the regional PM10 emissions. 

On the other hand, when vehicles travel over unpaved roads they directly disturb the 

surface and create PM10 emissions, which also contribute to the regional PM10 problem 

at a rate of about 9 percent of the total. By the end of June 2003, Clark County and 

other local governments had paved all unpaved roads in the PM10 nonattainment area 

with an ADT of 150 or more. By March 2004, the local governments had paved all 

unpaved roads with an ADT of 100 or more. This fully implements the road paving 

contingency measure set forth in Section 4.6.3 of the PM10 SIP. These actions were 

documented in the Clark County PM10 State Implementation Plan Milestone 

Achievement Report dated June 2007 and submitted to EPA Region 9 by the Nevada 

Division of Environmental Protection on October 3, 2007. In addition to PM10 emissions 

linked to travel on paved and unpaved roads, there are several other PM10 emission 

sources that must be accounted for within the transportation conformity process. These 

include: 

• Vehicular exhaust, 

• Vehicular brake wear, 

• Vehicular tire wear and 

• Road construction.2

 

Table 27. Roadway Silt Loading Factors 

Paved Roads 

Roadway Category 2006 

Ext. Connector 0.470 

Freeway Ramps 0.620 

Minor Arterial 0.470 

Major Arterial 0.490 

Ramps 0.620 

Interstate 0.020 

Freeway 0.020 

Expressway 0.020 

Collector 0.620 

Local 1.720 

Inter-Zonal Trips 1.720 

Public Transit 0.014 

 

2

 Note that road construction is treated the same way that general construction is treated - all applicable 

dust control regulations are applied to the site during construction activity to ensure emission reductions. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 49 

7.2. PM10 Emission Budgets for the Annual and the 24 Hour NAAQS 

and PM10 Emissions For Paved Roads 

The SIP budgets provide a stepped approach to achieving the NAAQS for PM10, with a 

2006 budget for the 24-hour standard. The reduction in the mobile source emission 

budget between the years 2003 and 2006 reflects the effectiveness of the control 

strategies for both construction activities and the stabilization of disturbed lands as 

defined within the 2001 PM10 SIP; see pages 5.33 - 5.36 of the 2001 PM10 SIP. Table 

27. identifies the PM10 roadway silt loading rates developed from the most recent silt 

sampling data. 

 

7.2.1. VMT and Silt Loading 

The silt loading factors in Table 27 are based on silt sampling that occurred in 2003, 

2004 and 2005 as part of Clark County’s 2001 SIP commitments. A number of silt 

sampling sites were kept constant during the 2000 through 2005 sampling periods. As 

a result, several of the sampling sites were impacted by construction activity track-out 

during the 2003 through 2005 sampling period. This data reflects current actual silt 

loadings on Las Vegas Valley roadways, including roads impacted by construction 

activity track-out. As shown in Table 27, there is a big difference between the dust 

emissions from the various roadway facility types, from 0.1 grams per vehicle-mile on 

Interstates to over 1 gram per vehicle-mile on local roads. However, there is no 

differentiation between the factors that apply in different parts of the valley. 

7.2.2. Unimproved Shoulder Calculation: SIP Control 

Implementation Schedule 

Calculations for roadways with unimproved shoulders come directly from data 

developed by Clark County in support of the PM10 SIP. Based on the programming of 

CMAQ funds to reduce/eliminate roadways with less than 28' of paving, the SIP 

roadway remediation schedule is as follows: 

• 50 percent in 2004 

• 25 percent in 2005 

• 25 percent in 2006 

It is assumed there will be no significant area of unpaved shoulders remaining 

after 2006.

7.3. PM10 Roadway Emissions Calculation 

Table 28 shows the calculation of PM10 emissions from paved roadways based on these 

current silt loading factors and average vehicle fleet weight. Clark County DAQEM 

conducted an assessment of average fleet vehicle weight using Nevada Department of 

Motor Vehicles data through 2005. Based on this assessment, it was determined that 

the 2006 average vehicle fleet weight for Clark County was 2.29 tons. The results were 

published in a report titled Average Vehicle Fleet Weight in Clark County, Nevada, 

dated January, 2006. The findings were presented to the Clark County Technical 

Advisory Committee for comment and reviewed by EPA Region 9 staff.
 50 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

7.4. PM10 Emissions from Vehicles 

The SIP emission rates for on-road mobile sources, including actual vehicle emission 

calculations for Vehicular Sulfate Particulate Matter, Tire Wear, Brake Wear and 

Exhaust Particles are set out in Table 29. 

For this conformity analysis, the DAQEM advises that, in view of the minimal difference 

between the rates for the various facility types, it is acceptable to use a single rate for all 

VMT in each horizon year analysis. The rate for 2006 is 0.072 grams per vehicle-mile. 

The rate for 2006 is used for all subsequent years, as shown in Table 30. 

7.5. Roadway Construction PM10 Emissions 

A series of PM10 inventories were conducted during the 1999-2000 period in support of 

the SIP development. The following identifies the assumptions for the purpose of 

estimating PM10 from highway construction. 

7.6. Roadway Construction PM10 Emissions 

A series of PM10 inventories were conducted during the 1999-2000 period in support of 

the SIP development. The following identifies the assumptions for the purpose of 

estimating PM10 from highway construction. 

CONSTRUCTION: Highway Construction PM10 Emission Rates 

• Calculate total number of months for analysis period 

• Convert the Lane Miles of Project to Acres 

5280 x 12 (average lane width) = 63,360 square feet in a lane mile 

63,360/43,560 (number of square feet in an acre) = 1.45 acres per lane mile 

Factor: 1.45 x total project lane mile = number of acres under construction

• Apply SIP emission factor = .42 tons/month = 840 pounds/acre/month 

• Apply Best Management Practice reduction factor to total acres under 

construction = Product - (product x .68) 

• Convert to Average Day Emissions: divide by 30.5 (annual average days in 

month) and divided by total number of month for analysis period 

WIND EROSION: Highway Construction Emission Calculations for PM10

• Define Project Acres

Obtain acre calculation for analysis period from Step 1 of Highway Construction. 

• Apply PM10 Wind Erosion Rates Per Day to Acre Calculation

35% of Acres x 7.60 x 10-4 tons 

65% of acres x 1.98 x 10-2 tons 

• Define Total Daily Wind Erosion

Add products from Step 2 

• Apply Sections 90 through 94 Regulations

Reduce by 71% 

These rates are applied to the estimated acreage covered by highway construction 

projects, and the results are set out in Table 30. For the years 2003 through 2005, 

acreages have been calculated based on projects identified in the TIP. The average of 

these three years is used as a basis for 2006 and subsequent years 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 51 

Table 28. PM10 Roadway Analysis for Horizon Years 

2006 2013 2020 2030

Facility Type

Adjusted 

2013 

AAWDVMT

Adjusted 

2020 

AAWDVMT

Adjusted 

2030 

AAWDVMT

PM10 

Emission 

Factors 

(g/v-m)

Paved 

Road 

Emissions 

(kg/day)

Paved 

Road 

Emissions 

(kg/day)

Paved 

Road 

Emissions 

(kg/day)

External connectors 290,372 343,717 426,371 1.85 537 636 789

System Ramps 484,480 552,264 749,713 2.215 1,073 1,223 1,661

Minor Arterials 6,913,064 9,483,163 11,243,333 1.85 12,789 17,544 20,800

Major Arterials 16,158,628 18,868,310 20,686,624 1.901 30,718 35,869 39,325

Ramps 1,399,312 1,674,907 1,873,418 2.215 3,099 3,710 4,150

Interstates 11,098,518 14,559,764 18,038,688 0.238 2,641 3,465 4,293

Freeways 5,869,720 7,934,791 9,404,817 0.238 1,397 1,888 2,238

Beltway 759 1,824 1,484,200 0.238 0 0 353

Collectors 3,985,159 4,539,278 5,426,105 2.215 8,827 10,055 12,019

Centroid connectors 3,888,323 4,788,550 5,326,531 1.901 7,392 9,103 10,126

Other Local Roads 58,200 66,316 98,544 4.299 250 285 424

HOV Lanes 297,116 393,743 1,833,031 0.238 71 94 436

Public Transit Bus 56,686 68,023 68,023 4.299 244 292 292

Intra-zonal 185,167 189,624 216,687 4.299 796 815 932

DAILY TOTALS 50,685,502 63,464,276 76,876,086 69,835 84,980 97,838

Convert to US tons per day 0.001102 0.001102 0.001102

PM10 Emissions (Tons per day) 77.0 93.6 107.8

2006 Mobile Source PM10 Emissions Budgets for the Las Vegas Valley 141.41 141.41 141.41

AAWDVMT=Average Annual Week Day Vehicle Miles Traveled. Transit Daily Miles was provided by the RTC Transit Department 8-

13-2008. Source: Regional Transportation Commission staff

Table 29. Mobile Source PM10 Emission Factors 

(Grams per Vehicle-Mile) 

Roadway Category 2013 2020 2030 

Ext. Connector 0.0275 0.026 0.0257 

Freeway Ramps 0.0275 0.026 0.0257 

Minor Arterial 0.0275 0.026 0.0257 

Major Arterial 0.0275 0.026 0.0257 

Ramps 0.0275 0.026 0.0257 

Interstate 0.0275 0.026 0.0257 

Freeway 0.0275 0.026 0.0257 

Expressway 0.0275 0.026 0.0257 

Collector 0.0275 0.026 0.0257 

Local 0.0275 0.026 0.0257 

Inter-Zonal Trips 0.0275 0.026 0.0257 

Public Transit 0.0275 0.026 0.0257 

Source: DAQEM 

Table 30. PM10 Vehicle Emissions 

 2013 2020 2030 

AAWDVMT 44,793,987 56,020,120 67,921,978 

Vehicle Emissions Factor (gm/v-m) 0.0275 0.026 0.0257 

PM10 Vehicle Emissions (kg/day) 1,232 1,457 1,746 

PM10 Vehicle Emissions (tons/day) 1.36 1.61 1.92 

Source: DAQEM 
 52 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 30. PM10 Emissions from Highway Construction and Wind Erosion 

2013 2020 2030

SOURCE Link Lane Link Lane Link Lane 

CONSTRUCTION

Construction Miles 110.9 679.4 122.2 786.1 296.8 1105.0

Horizon Year Total Projects 144 104 58

Number of months in Horizon Year 60 84 24

Estimated Acreage 985 1140 1602

Emissions Factors (tons/acre/mon) 0.42 0.42 0.42

PM10 Vehicle Emission (tons/day) 0.2261 0.1869 0.9193

Best Practices Reduction (%) 68% 68% 68%

Net PM 10 Emissions (tons/day) 0.07235 0.0598 0.2942

WIND EROSION

Estimated Acreage 985 1140 1602

Erosion Rate (tons/acre/day) 35% of site 0.00076 0.0008 0.0008

65% of site 0.0198 0.0198 0.0198

PM10 Emissions (tons/day) 0.27 0.31 0.4544

Sections 90-94 Reduction (%) 71% 71% 71%

Net PM 10 Emissions (tons/day) 0.19097 0.2193 0.3226

Source: Regional Transportation Commission staff. 

7.6.1. More about Particulate Matter (PM10) Analysis Methodology 

Year 2007 serves as the “base” and form the basis for each later scenario, The horizon 

years 2013 and 2020, serve as intermediate analysis points. The long-range horizon 

year of the transportation plan's forecast period, the year 2030, shall be the final 

emissions analysis year. 

The PM10 emissions predicted by the horizon year scenarios, defined in above, shall be 

less than the mobile source emission budget established in the 2001 PM10 SIP. The 

approved PM10 mobile source emissions budget is 141.41 tons per day for 2006 and 

successive planning horizon years. 

The Table 31 summarizes the calculation of total PM10 mobile source emissions for 

each of the horizon analysis years. 

Table 31. Total PM10 Mobile Source Emissions Per Day for Horizon Years 

SOURCE 2013 2020 2030 

Paved Road Dust 76.96 93.65 107.82

Vehicle Emissions 1.53 1.81 2.17

Highway Construction 0.07 0.06 0.29

Windblown Construction Dust 0.19 0.22 0.32

PM10 Mobile Source Emissions 78.75 95.74 110.60

BUDGET 141.4 141.4 141.4

Source: Regional Transportation Commission staff. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 53 

8. Ozone Modeling Assumptions 

Currently, there is no Ozone O3 budget for the RTC modeling area. The EPA gave nonattainment areas until 2008 to develop a new SIP and mobile source budget for O3. In 

the absence of an emission budget, the RTC will compare the “Action” scenario versus 

the “No Build” scenario as defined in 40 CFR Part 93. The regulatory prescribed 

comparison is structured as follows. 

Travel demand (VMT) and the associated emission estimates are generated for future 

travel under two scenarios. For the “Action” scenario all travel is loaded onto the 

“anticipated” built network as defined in the project listing that comprises the 2013-2030 

project list in the RTP. The emission estimates are calculated for the “Action” scenario 

by required horizon years, i.e., 2013, 2020 and 2030. The emission output for the 

“Action” scenario is compared against the “No Build” scenario for each of the horizon 

years. If the “Action” scenario emission estimates are less than the “No Build” for each 

of the horizon years, the region is determined to be in positive transportation conformity 

for O3. 

The “No Build” scenario is defined as: 1) the in-place roadway network as of RTP’s start 

year of 2009, 2) assumption of the continuation of all ongoing travel demand 

management and/or transportation system management activities, 3) the continued 

application of any SIP mandated control measures, and 4) inclusion and assumption of 

completion for all “ongoing” roadway construction projects. Except for the model 

networks are coded as No Build or Action scenarios, the same travel demand input files 

based on the same land use information were applied into the model for the “Action” 

scenario and the “No Build” scenario for each of the horizon years. 

8.1. Estimating Regional Travel for Ozone Conformity 

The RTC estimates travel by horizon years for CO and PM10 utilizing the regional travel 

demand model, which encompasses the Las Vegas urban area. The non-attainment 

area for O3 is larger than the extent of the travel model domain the RTC maintains. 

Therefore, the RTC estimates regional travel for the roadway network outside of the 

urban area. Working with NDOT, RTC estimated VMT and travel speeds for the 

roadway network outside of the urban area. This included segments of I-15, US 93, US 

95, State Route (SR) 157, SR 158, SR 159, SR 160, SR 161, SR 163, SR 164, SR 167, 

SR 168 and roadways in Laughlin. VMT estimates were based on regression analysis 

data provided by NDOT. Travel speed estimates were based on data published in 

NDOT’s Annual Speed Monitoring Report Details.

8.2. Ozone Roadway Emissions Calculation 

Tables 32A through 32C display the results of air quality modeling for O3. The modeling 

process uses levels of nitrous oxides (NOx) and volatile organic compounds (VOC), 

precursors of O3, to forecast the effectiveness of the RTP/TIP on levels of O3. Mobile 
 54 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

6.2 was run to obtain the NOx and VOC emission factors for urbanized areas and these 

factors were applied to the corrected, adjusted and modeled VMT. 

Mobile 6.2 was run separately to obtain the emission parameters for Rural Areas and 

these emission factors were applied to the VMT outside the modeling areas. As Tables 

33 – 34 show that emissions from outside modeling areas are constant for the same 

horizon years regardless of Build or No Build. The Total NOx and VOC emissions should 

include all emissions outside the modeling area but within the Ozone Non – attainment 

boundary, but this inclusion does not change the results of the Build versus No-Build 

tests for the analysis on Ozone pollutants. Table 35 shows the total NOx and VOC 

emissions including the emissions within the modeling area, and the areas outside 

modeling area but within the boundaries of the Ozone Nonattainment Areas for all 

horizon years. 

Table 32A. 2013 Horizon Year VOC and NOx Emissions for TDF Modeling Area 

NOx (tons/day) VOC (tons/day) Build vs. No Build 

ROAD TYPE 

Build No 

Build

Build No 

Build

NOx VOC 

External 0.14 0.14 0.17 0.17 0.00 0.00 

System-to-system Ramp 0.24 0.25 0.27 0.28 -0.01 -0.01 

Minor Arterial 3.47 3.47 4.75 4.80 -0.01 -0.06 

Major Arterial 8.68 8.69 13.51 13.61 -0.01 -0.10 

Ramp 0.69 0.69 0.78 0.79 0.00 -0.01 

Interstate 5.91 6.01 8.52 9.33 -0.10 -0.81 

Freeway 2.90 2.91 3.40 3.48 0.00 -0.08 

Expressway 0.00 0.00 0.00 0.00 0.00 0.00 

Collector 2.01 2.01 2.87 2.90 0.00 -0.03 

Centroid 2.13 2.13 3.59 3.59 0.00 0.00 

Local 0.03 0.03 0.05 0.05 0.00 0.00 

HOV 0.12 0.12 0.12 0.12 0.00 0.00 

TOTAL EMISSIONS 26.30 26.44 38.04 39.13 -0.14 -1.09 

Source: Regional Transportation Commission staff. Same for Tables 32B and 32C. 

 

Table 32B. 2020 Horizon Year VOC and NOx Emissions for TDF Modeling Area 

NOx (tons/day) VOC (tons/day) Build vs. No Build 

ROAD TYPE 

Build No 

Build

Build No 

Build

NOx VOC 

External 0.08 0.08 0.13 0.13 0.00 0.00 

System-to-system Ramp 0.14 0.14 0.19 0.19 0.00 0.00 

Minor Arterial 2.49 2.49 4.52 4.50 0.00 0.02 

Major Arterial 5.39 5.39 10.74 10.69 0.00 0.05 

Ramp 0.42 0.42 0.57 0.57 0.00 0.00 

Interstate 4.12 4.13 8.36 8.46 -0.01 -0.10 

Freeway 2.02 2.05 3.11 3.26 -0.03 -0.15 

Expressway 0.00 0.00 0.00 0.00 0.00 0.00 

Collector 1.17 1.18 2.08 2.11 -0.01 -0.03 

Centroid 1.35 1.35 2.88 2.88 0.00 0.00 

Local 0.02 0.02 0.04 0.04 0.00 0.00 

HOV 0.08 0.07 0.11 0.10 0.01 0.01 

TOTAL EMISSIONS 17.27 17.31 32.73 32.92 -0.04 -0.18 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 55 

 

 

Table 32C. 2030 Horizon Year VOC and NOx Emissions for TDF Modeling Area 

NOx (tons/day) VOC (tons/day) Build vs. No Build 

ROAD TYPE 

Build No 

Build

Build No 

Build

NOx VOC 

External 0.07 0.07 0.13 0.13 0.00 0.00 

System-to-system Ramp 0.13 0.11 0.20 0.17 0.02 0.03 

Minor Arterial 2.14 2.33 4.52 5.13 -0.19 -0.61 

Major Arterial 4.43 4.72 10.75 11.91 -0.29 -1.16 

Ramp 0.34 0.33 0.50 0.49 0.01 0.01 

Interstate 3.76 3.73 10.43 11.69 0.03 -1.25 

Freeway 1.74 1.68 3.37 3.14 0.06 0.23 

Expressway 0.59 0.58 3.72 3.65 0.01 0.06 

Collector 1.01 1.11 2.18 2.33 -0.10 -0.15 

Centroid 1.07 1.08 2.72 2.73 0.00 -0.01 

Local 0.02 0.02 0.05 0.05 0.00 0.00 

HOV 0.27 0.08 0.48 0.12 0.19 0.35 

TOTAL EMISSIONS 15.57 15.84 39.05 41.55 -0.26 -2.49 

Table 33A. Interstate and Major Road NOx Emissions Outside TDF Modeling Area VMT 

and Emission Factors 

Outside Corridor Horizon Year VMT Emission Factors 

 VMT Ave 2013 2020 2030 

2013 2020 2030 Speed NOX VOC NOX VOC NOX VOC 

104,000 128,180 152,100 35 0.849 0.538 0.42 0.38 0.292 0.318 

88,000 95,200 108,000 40 0.864 0.517 0.43 0.36 0.296 0.303 

5,250 5,614 7,875 45 0.897 0.5 0.44 0.35 0.304 0.29 

2,800 2,800 2,800 45 0.897 0.5 0.44 0.35 0.304 0.29 

8,400 9,600 10,920 45 0.897 0.5 0.44 0.35 0.304 0.29 

96,000 110,000 125,000 50 0.951 0.486 0.46 0.34 0.316 0.28 

103,040 137,200 182,000 55 1.031 0.474 0.49 0.33 0.334 0.273 

74,480 89,300 123,500 55 1.031 0.474 0.49 0.33 0.334 0.273 

12,240 13,716 16,470 55 1.031 0.474 0.49 0.33 0.334 0.273 

208,000 208,000 275,600 55 1.031 0.474 0.49 0.33 0.334 0.273 

169,000 205,400 221,195 60 2.055 0.432 0.83 0.31 0.488 0.263 

48,000 55,000 62,500 65 2.102 0.432 0.851 0.309 0.497 0.263 

7,840 9,400 13,000 65 2.102 0.432 0.851 0.309 0.497 0.263 

11,400 13,050 15,900 65 2.102 0.432 0.851 0.309 0.497 0.263 

888,000 1,140,000 1,440,000 70 2.102 0.432 0.851 0.309 0.497 0.263 

18,810 20,350 24,200 70 2.102 0.432 0.851 0.309 0.497 0.263 

165,600 204,000 252,000 70 2.102 0.432 0.851 0.309 0.497 0.263 

38,400 43,680 53,640 70 2.102 0.432 0.851 0.309 0.497 0.263 

22,000 26,000 31,200 70 2.102 0.432 0.851 0.309 0.497 0.263 

675,840 816,000 1,008,000 75 2.102 0.432 0.851 0.309 0.497 0.263 

Source: Emission factors from Mobile 6 Rural Run results. VMT from Regional Transportation Commission staff. See tables in 

previous section. 
 56 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 33B. NOX and VOC Emissions From Interstate, Highways and Major Arterials 

Outside Modeling Area

Outside Corridor VMT 2013 Emissions 2020 Emissions 2030 Emissions

2013 VMT 2020 VMT 2030 VMT NOX VOC NOX VOC NOX VOC

104,000 128,180 152,100 88,296 55,952 53,707 48,068 44,413 48,368

88,000 95,200 108,000 76,032 45,496 40,460 34,177 31,968 32,724

5,250 5,614 7,875 4,709 2,625 2,465 1,942 2,394 2,284

2,800 2,800 2,800 2,512 1,400 1,229 969 851 812

8,400 9,600 10,920 7,535 4,200 4,214 3,322 3,320 3,167

96,000 110,000 125,000 91,296 46,656 50,710 36,850 39,500 35,000

103,040 137,200 182,000 106,234 48,841 67,640 45,002 60,788 49,686

74,480 89,300 123,500 76,789 35,304 44,025 29,290 41,249 33,716

12,240 13,716 16,470 12,619 5,802 6,762 4,499 5,501 4,496

208,000 208,000 275,600 214,448 98,592 102,544 68,224 92,050 75,239

169,000 205,400 221,195 347,295 73,008 171,304 63,469 107,943 58,174

48,000 55,000 62,500 100,896 20,736 46,805 16,995 31,063 16,438

7,840 9,400 13,000 16,480 3,387 7,999 2,905 6,461 3,419

11,400 13,050 15,900 23,963 4,925 11,106 4,032 7,902 4,182

888,000 1,140,000 1,440,000 1,866,576 383,616 970,140 352,260 715,680 378,720

18,810 20,350 24,200 39,539 8,126 17,318 6,288 12,027 6,365

165,600 204,000 252,000 348,091 71,539 173,604 63,036 125,244 66,276

38,400 43,680 53,640 80,717 16,589 37,172 13,497 26,659 14,107

22,000 26,000 31,200 46,244 9,504 22,126 8,034 15,506 8,206

675,840 816,000 1,008,000 1,420,616 291,963 694,416 252,144 500,976 265,104

Convert to US Tons Per Day (Kg/day by /1000, tons by * 0.001102) 0.00000110

TOTAL 

2,747,100 3,332,490 4,125,900 5.48 1.35 2.78 1.16 2.06 1.22

Source: Regional Transportation Commission staff. 

Table 34A. 2013 Minor VOC Emissions Outside TDF Modeling Area 

Speed

VOC 

emission 

factor

NOX 

emission 

factor Total VMT

VOC 

emissions 

NOX 

emissions 

Minor Arterials 35 0.538 0.849 41,098 22,111 34,893

Collectors 30 0.57 0.862 34,776 19,822 29,977

Other Local Roads 25 0.898 0.61 29,507 26,497 17,999

Convert to US Tons Per Day (Kg/day by /1000, tons by * 0.001102) 0.00000110

TOTAL 105,380 0.08 0.09

Source: Regional Transportation Commission staff. 

Table 34B. 2020 Minor Year NOx Emissions Outside TDF Modeling Area 

Speed

VOC 

emission 

factor

NOX 

emission 

factor Total VMT

VOC 

emissions 

NOX 

emissions 

Minor Arterials 35 0.375 0.419 65,103 24,414 27,278

Collectors 30 0.399 0.427 55,088 21,980 23,522

Other Local Roads 25 0.447 0.43 46,741 20,893 20,099

Convert to US Tons Per Day (Kg/day by /1000, tons by * 0.001102) 0.00000110

TOTAL 166,932 0.07 0.08

Source: Regional Transportation Commission staff. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 57 

Table 34C. 2030 Minor VOC Emissions Outside TDF Modeling Area 

Speed

VOC 

emission 

factor

NOX 

emission 

factor Total VMT

VOC 

emissions 

NOX 

emissions 

Minor Arterials 35 0.318 0.292 101,041 32,131 29,504

Collectors 30 0.341 0.299 85,496 29,154 25,563

Other Local Roads 25 0.37 0.314 72,542 26,841 22,778

Convert to US Tons Per Day (Kg/day by /1000, tons by * 0.001102) 0.00000110

TOTAL 259,080 0.10 0.09

Source: Regional Transportation Commission staff. 

Table 35. TOTAL NOx and VOC Emissions for Horizon Years 

2013 2020 2030

TYPE

Build No 

Build

Build No 

Build

Build No 

Build

Build No 

Build

Build No 

Build

Build No 

Build

Modeled Emission 26.30 26.44 38.04 39.13 17.27 17.31 32.73 32.92 15.57 15.84 39.05 41.55

Highway Emission

Outside Model Area 5.48 5.48 1.35 1.35 2.78 2.78 1.16 1.16 2.06 2.06 1.22 1.22

Local Emission

Outside Model Area 0.08 0.08 0.09 0.09 0.07 0.07 0.08 0.08 0.10 0.10 0.09 0.09

TOTAL 31.85 31.99 39.49 40.58 20.13 20.17 33.97 34.16 17.73 18.00 40.36 42.85

NOx 

(tons/day)

VOC 

(tons/day)

NOx 

(tons/day)

VOC 

(tons/day)

NOx 

(tons/day)

VOC 

(tons/day)

Source: Regional Transportation Commission staff. 

9. Finding of Conformity 

It is a requirement of Federal and State Conformity Regulations that the projected 

mobile source emissions for the Non-attainment Area for the pollutants should be lower 

than the Budgets contained in the State Implementation Plans. 

For CO, the projected net mobile source emissions are compared with the Mobile 

Source Emissions Budgets set out in the September 6, 2006 amendment to the “Carbon 

Monoxide State Implementation Plan for the Las Vegas Valley Nonattainment Area” 

Clark County Board of Commissioners, August 2000. For PM10, the projected 

emissions resulting from the process described in Section 5.6 are compared with the 

Mobile Source Emissions Budgets set out the “PM10 State Implementation Plan for 

Clark County, Nevada”. For O3, the projected emissions resulting from the process 

described in Section 8 are compared with the “No Build” scenario as defined in 40 CFR 

Part 93. 

As shown in Table 36, these tests of conformity are satisfied for all pollutants. 
 58 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 36. Conformity Test Summary 

CO (tons/day) PM10 (tons/day) 

Year Emissions 

Emissions 

Budget 

Conformity 

Requirement Emissions

Emissions 

Budget 

Conformity 

Requirement 

2010 378 690 Satisfied 

2013 375 690 Satisfied 78.75 141.44 Satisfied 

2015 384 768 Satisfied 

2020 400 817 Satisfied 95.74 141.44 Satisfied 

2030 463 817 Satisfied 110.60 141.44 Satisfied 

NOx (tons/day) VOC (tons/day) 

Year Build No Build 

Conformity 

Requirement Build No Build 

Conformity 

Requirement 

2013 31.85 31.99 Satisfied 39.49 40.58 Satisfied 

2020 20.13 20.17 Satisfied 33.97 34.16 Satisfied 

2030 17.73 18.00 Satisfied 40.36 42.85 Satisfied 

Based on the foregoing analysis, the projects and programs contained in the 

Regional Transportation Plan FY 2009-2030 found to be in conformity with the 

requirements of the Clean Air Act Amendments of 1990, the relevant sections of 

the Final Conformity Rule 40 CFR Part 93 and the procedures set forth in the 

Clark County Transportation Conformity Plan. 

9.1. Transportation Control Measures 

A second component of conformity determination is an assessment of the progress in 

implementing TCMs. These measures are intended to reduce emissions or 

concentrations of pollutants from transportation sources by reducing vehicle use or 

otherwise reducing vehicle emissions. 

As part of the conformity process, the RTC must certify that TCMs identified in the SIPs 

are either programmed or are being implemented on schedule and that no Federal 

funds are being diverted from these projects in such a way as to delay their timely 

implementation. Due to the length of the text and the level of detail associated with the 

control measures discussion for both CO and PM10, this analysis will not extend further 

discussion here. 

9.1.1. Statement of TCM Progress 

As required by 23 CFR, Part 450.324, n(3), in non-attainment areas, the TIP must 

describe the progress in implementing any required TCMs, including any reasons for 

significant delays in the planned implementation and strategies for ensuring their 

advancement at the earliest possible time. The following table provides the existing 

status of TCMs from both the CO and PM10 SIPs. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 59 

9.1.2. Transportation Control Measure Certification 

The RTC of Southern Nevada certifies that TCMs identified in the both the 2000 CO SIP 

and the 2001 PM10 SIP are being implemented on schedule and that no Federal funds 

are being diverted from these projects in such a way as to delay their timely 

implementation. Table 37 lists some of the adopted mobile source TCMs. 

Table 37. Status of Adopted Mobile Source Transportation Control Measures 

Carbon Monoxide 

Control Measures from 

2000 CO SIP 

Emission 

Reduction Status 

Voluntary Transportation 

Control Measure/TDM 0.08% Ongoing; the RTC's TDM program is described in detail in Section 4 

Alternative Fuels Program for 

Government Fleets 0.12% Ongoing; local government committed to alternative fuels program 

Previously Adopted 

Enforceable Control 

Measure 

Adoption 

Date Status 

Motor Vehicle Inspection & 

Maintenance Program 1978 Ongoing 

Fleet Over 1967 Ongoing 

Particulate Matter 10 Microns or Less (PM10) 

Control Measures from 

2001 PM10 SIP Status 

Paving of Unpaved Roads Ongoing contracts with member entities for paving; funds 

programmed into the TIP. 

Stabilize Narrow Roadway 

Shoulders Approved and programmed into the TIP. 

Transportation Construction - 

Rules 90-94 

Ongoing; all transportation construction projects must 

conform. All transportation construction contracts, 

regardless of funds source, include the requirement to 

conform to Rules 90-94. 

 
 60 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 61 

APPENDIX 4-A: 

RTC 2004 Regional Travel Demand 

Model Package 2 for 2009-2030 RTP 

Travel Demand Model 

Transit Processing and Mode Choice Modeling 

Capabilities 

Prepared for: 

Regional Transportation Commission 

of Southern Nevada 
 62 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

2009-2030 RTP Travel Demand Model - RTC 2004 

Regional Travel Demand Model Package 2 

Transit Processing and Mode Choice Modeling Capabilities - 

Basic Procedures

Introduction 

The RTC 2004 Regional Travel Demand Model Package 2 A (hereafter short for The 

RTC 2004 Model Pack 2) will be used for the 2009-2030 RTP. The RTC 2004 Model 

Pack 2 adds transit processing and mode choice modeling capabilities to the RTC 2004 

Regional Travel Demand Model (hereafter short for The RTC 2004 Model) that was 

used in the 2006-2030 RTP. 

The RTC 2004 Model represents an evolution of travel forecasting models and model 

components specifically developed for the Las Vegas Valley portion of Clark County. 

Model components for trip generation, trip distribution, and auto occupancy models 

were re-estimated based on the 1996 regional travel survey. In addition, 2000 Census 

data were used to update socioeconomic sub-models for trip generation and to reexpand the 1996 travel survey data. (for model details, refer to RTC 2004 Regional 

Travel Demand Model). The RTC 2004 Model has been updated to the RTC 2004 

Model Pack 2 by including additional and optional transit processing and mode Choice 

modeling capabilities. This document provides a description of the basic procedures 

included in the RTC 2004 Model Pack 2: 

• Transit network coding procedures 

• Transit path-building and skimming procedures 

• Mode choice procedures 

• Transit assignment procedures 

The simplified mode split procedure in the RTC 2004 Model continues to be used for 

forecasts not requiring detailed mode choice processing. Results from the detailed 

procedures described in this document can be aggregated and summarized at the 

district level to provide input for the simplified mode split procedures. If the proposed 

changes are sufficiently large (e.g. the widening of an interstate freeway), it might be 

reasonable to use the simplified mode split for initial planning forecasts and then use 

the detailed transit modeling and mode choice procedures described in this chapter for 

final alternative testing. 

Transit Network Description 

For the base year or currently, the Citizens Area Transit (CAT) provided public 

transportation services for the Las Vegas Valley. Fixed-route local bus service provide 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 63 

the bulk of the existing transit system with limited stop service and express service 

being. Most bus routes provided 30 minute headways throughout the day; several 

routes offered 24-hour service but with 45 minute or 60 minute headways during the 

“owl” service. In 2004, the monorail serving the Las Vegas Strip and the MAX bus rapid 

transit (BRT) demonstration project on North Las Vegas Boulevard were opened. The 

transit routes, including local bus, limited bus, express bus and premium services for the 

base year and future years were coded into the TransCAD network for the model. The 

following Figure1 shows the transit system that existed in 2002-2003 as an example. 

YEAR 2000 - TRANSIT ROUTES

Figure 1: 2002-2003 CAT Bus Routes

Para-transit services are also provided in the region. CAT provides a several fixed 

routes that serve retirement communities, shopping areas, and establishments which 

provide services to seniors. The routes offer limited services two days each week. 

These routes are not considered part of the modeled transportation system. 

While all current transit services provide relatively balanced services throughout the 

day, both peak and off-peak transit networks are coded for the modeling process. This 
 64 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

approach provides the capability to analyze future alternatives that vary service by timeof-day. 

Transit speeds have been coded to reflect the schedule nature of transit service but 

also taking into consideration prevailing roadway speeds for mixed flow operations. 

Scheduled time points for the transit service were recorded on the coded transit network 

for the morning peak, afternoon peak, and off-peak periods. The travel times on links 

between time points were estimated by prorating the scheduled travel times over those 

links on a route-by-route basis. The resulting average speeds on links were 

summarized by facility type, area type, and time-of-day for each route. Modeled 

congested speeds are updated within the modeling process by running several 

iterations of the entire modeling process until final assigned roadway speeds reasonably 

match the roadway network speeds used for trip distribution and mode choice. 

Transit speeds for premium transit services will be estimated for each alternative based 

on the operating characteristics of the alternative, station spacing, and station dwell 

times. In general, transit speeds for premium transit services will be unaffected by 

changes in modeled congested speeds on roadways. 

Transit Access Coding 

Walk Access 

Substantial effort was expended to determine appropriate walk access coding 

conventions for the RTC 2004 Pack 2. Since walk access distance data were not 

recorded for the 2002 on-board survey, the “best” walk access coding distance was 

determined through multiple assignments of the observed trip tables derived from the 

2002 survey data to the 2002 network. The resulting modeled boardings by line were 

compared to observed boardings by line. This effort was part of the determination of 

transit path-building parameters. 

The best results were obtained when walk access was coded to all transit within 1.25 

miles of a TAZ. 

Walk access distances were varied by trip purpose and income group being modeled. 

The variation in walk access distances reflect the fact that lower income groups are 

more likely to be captive and, thus, more likely to walk longer distances to access transit 

than higher income groups. About 80 percent of the linked transit trips summarized 

from the 2002 CAT on-board survey were made by travelers reporting low or lowermiddle incomes. The walk access distances also reflect that residents do not walk long 

distances to transit for non-home-based trips and, likewise, that visitors do not walk long 

distances to transit. 

Two different transit networks (peak and off-peak) are each used for path-building. 

Value-of-time is also varied for the path-building process. Two different value-of-time 

assumptions are used for the visitor paths. In total, five different sets of walk access to 

transit skims are built. Table 1 shows the walk distances for transit path-building for 

different trip purposes and different income groups. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 65 

Table 1: Walk Distances for Transit Path-Building 

Trip Purpose Income Group Network 

Used 

Maximum 

Walk 

Access 

Distance 

(Miles) 

Maximum 

Walk 

Transfer 

Distance 

(Miles) 

Walk 

Speed 

(MPH) 

Home-Based Work Low & Lower Middle Peak 1.25 0.25 3 

Home-Based Work Upper-Middle & High Peak 0.5 0.25 3 

Home-Based Non-Work All Off-Peak 0.5 0.25 3 

Non-Home-Based All Off-Peak 0.5 0.25 3 

All Visitor All Off-Peak 0.5 0.25 3 

Walk access is allowed to occur over the coded roadway network provided the network 

link is not part of a limited access facility (interstate, freeway, expressway, system ramp 

or ramp). In all cases, transfer walk times are limited to one-quarter mile (five minutes). 

All walk access and walk transfer are assumed to occur at a three mile per hour 

average walking speed. 

Drive Access 

While there is very little formal park-and-ride facilities and existing auto access to transit 

in the Valley, park-and-ride might be a very important component of future alternatives. 

The recently opened (2003/2004) South Strip Transit Terminal provides parking along 

with facilitating transfers between CAT fixed routes and bus lines. For future 

alternatives, drive access will be allowed to premium transit stations with proposed 

formal park-and-ride lots. Bicycle, drop off and other access will also be considered as 

“walk” access. 

Transit Path-Building 

Impedances for path-building consider fares and weighted travel times. Since 

relationships between fares, in-vehicle time, wait-time, and walk time vary by trip 

purpose (and income group for home-based work trips), maintaining complete

consistency between path-building and mode choice parameters would require runs of 

transit path-builder for trip purpose and income group for which the mode choice model 

has been calibrated. This would imply building 13 different sets of transit paths for walk 

access to bus, alone. For the RTC 2004 Pack 2, some simplification has been 

assumed so that only five sets of walk access to bus transit paths need to be built. 

Since transit path-building considers transit fares paid, the current CAT system fare 

policy must be understood. That fare policy (as obtained from the RTC web-site) is as 

follows: 

Full Fare, Reduced Fare, Full and Reduced Passes, and Transfers. 

Based on an analysis of 2003 revenue and boarding information, the average fare for 

local bus service taking into account of discounts and passes was calculated; the 
 66 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

average fare paid for express buses were calculated too. The modeled fares are 

probably more consistent with the auto operating costs represented to the model. The 

“full fare” method has been used for path-building and modeling purposes. For 

the mode choice model application, fares are expressed in 1995 dollars. 

Value-of-time can be determined from the mode choice model. Again, for simplification, 

values-of-time have been combined for a number of trip purposes. All weighted time 

values were converted to monetary terms and combined with fares for path-building 

purposes. 

Improved model results were obtained if the added transfer penalties were also included 

in the mode choice models. Through calibrations, an added transfer penalty of seven 

minutes per transfer was found to produce reasonable results. 

The path-building weights will be used for transit path-building and transit assignment 

along with the trip purposes that will be modeled using each set of transit impedances. 

The transit assignments show that there is a high correlation between the modeled 

boardings by line and the observed boardings by line. See Table 2 as an example. 

Table 2: 2002 Transit Assignment Summary 

Measure Observed (Summarized from 

2002 CAT On-Board Survey) 

Assigned Observed 

Trip Tables 

Number of Linked Trips 109,282 109,282 

Total Boardings 142,744 150,360 

Boardings per Linked Trip 1.31 1.38 

Boardings by Type of Service 

 Local Bus 139,836 147,412 

 Limited Bus 2,320 2,642 

 Express Bus 588 306 

Coefficient of Determination (R2

) 0.96 

Root Mean Squared Error on Boardings 837 

Percent Root Mean Squared Error 26% 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 67 

0

5,000

10,000

15,000

20,000

25,000

0 5,000 10,000 15,000 20,000 25,000

Observed Boardings

Modeled Boardings

Local

Limited

Express

Figure 2: Assignment of Observed 2002 Linked Trips vs. 

Observed Boardings by Route

Mode Choice

Resident Trip Purposes 

Resources were not available for the full development of mode choice models for the 

Las Vegas Valley. Thus, the decision was made to transfer a model to the region and 

update the model constants to reproduce observed transit ridership for the region. 

Several donor models were considered. The Las Vegas Travel Demand Model was 

prepared by PBQ&D in 2001. This mode choice model was estimated based on the 

spring 1996 household survey supplemented with data from an on-board transit 

passenger travel survey performed in October and November 1995. Since the PBQ&D 

model offers the benefit of being estimated using local data, the use of the PBQ&D 

mode choice model as the donor model was reasonable. Figure 3 shows the structure 

of the PBQ&D model. 

The following changes were made to the PBQ&D model structure shown in Figure 3: 

• The 2004 RTC Model is a trip-based model that models all trips made in motorized 

vehicles. Trips made using non-motorized modes are not modeled. 

• Premium transit services such as the monorail and MAX BRT system are being 

planned and implemented in the Las Vegas region. Some of the service will offer 

multiple transit options within a corridor. For example, both the monorail and buses 

provide transit service on the Strip. Thus, a local / premium nest under the walk to 

transit access mode has been added to the mode choice model. Since park-and-
 68 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

ride lots are normally associated with premium transit services offered to outlying 

areas, there is little need to provide a local / premium nest under the drive access 

mode. 

Choice

Motorized

Auto Transit

Drive Alone Shared Ride

2 Person 3+ Person

Walk Access Drive Access

Local Bus Park-andRide

Kiss-andRide

Walk/Bike

Figure 3: PBQ&D Mode Choice Model Structure

The analysis of toll roads is an increasing requirement in many regions, especially in 

fast growing areas like Las Vegas. A nesting structure for the testing of toll road 

alternatives could be added to the model under the drive alone, shared ride 2, and 

share ride 3+ nests. The toll road nest would need to be adapted from work performed 

elsewhere (e.g. Southern California). 

Since the average wage rates for each income group were known, the coefficients of 

cost for the home-based work mode choice model could be varied by income group to 

be more consistent with FTA guidelines. It’s interesting to note that the $6.12 per hour 

rate is within the FTA guidelines. Several changes were made to the original PBQ&D 

mode choice models for consistency with FTA guidelines or to enhance consistency 

with transit path-building procedures. Figure 4 shows the general mode choice model 

structure used for the 2004 RTC Park 2. The structure shown in Figure 4 is used for all 

resident trip purposes. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 69 

Choice

Auto Transit

Drive Alone Shared Ride Walk Access Drive Access

2 Persons 3+ Persons Local

Service

Premium

Service Drive Alone Drive Access

 

Figure 4 : 2004 RTC Mode Choice Model Structure

Visitor Trip Purposes 

The PBQ&D visitor models were adapted for use with the 2004 RTC Pack 2 with Mode 

Choice Analysis. The mode choice model structures and parameters for the three 

general types of visitor models were transferred for the 2004 RTC Pack 2. The generic 

multinomial mode choice structures for the three types of visitor models (multi-day 

visitors, single day visitors, and airport related trips) are shown in Figure 5 and Figure 6. 

Unlike, the models for residents of the region, the visitor models forecast all person 

trips, not just person trips made in motorized vehicles. Thus, walk skims are required 

for the mode choice model implementation. The walk skims are built over the coded 

roadway network links except freeway or ramp links. Several other “exotic” modes are 

included in the visitor mode choice models: taxi, shuttle bus, and tour bus. And, private 

auto must consider both autos privately owned by visitors and those rented by visitors. 

Choice

Walk Taxi Public Bus Shuttle Bus Premium Transit Private Auto

 Figure 5: 2004 RTC Pack 2 Mode Choice Model Structure – Multi-day & Single 

Day Visitor Trips
 70 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Choice

Private Auto Taxi Public Bus Shuttle Bus Tour Bus Premium Transit

 Figure 6: 2004 RTC Pack 2 Mode Choice Model Structure – Airport Trips

The originally transferred visitor models included 12 trip purposes. Several of the trip 

purposes were combined for mode choice modeling purposes. However, efforts were 

made to combine only those purposes that were relatively similar both in terms of the 

type of trip being modeled and in terms of model coefficients. Table 3 shows the 

original trip purposes and the combined purposes. 

As with the resident-based mode choice models, a coefficient on the number of 

transfers was added to the visitor and airport models. The coefficient for each transfer 

was set to be equivalent to seven minutes of in-vehicle travel time. 

Mode choice model parameters and mode specific constants for the visitor and airport 

models are shown in Table 4. Note that the taxi base fare is fixed and could effectively 

be incorporated into the taxi mode constant. However, incorporating the fixed values as 

input constants allows for the consideration of policy changes such as a cutting the 

frequency of shuttle service if fixed guideway transit to the airport is provided or 

changing the “drop fare” for taxi service. 

Table 3: Combination of Visitor Trip Purposes for Mode Choice

Original Trip Purpose Combined Trip Purpose 

Hotel-Based Convention 

Hotel-Based Business Hotel-Based Convention / Business 

Hotel-Based Gaming Hotel-Based Gaming 

Hotel-Based Other Hotel-Based Other 

Non-Hotel-Based Gaming 

Non-Hotel-Based Other 

Single-Day Non-Airport-Based Business 

Single-Day Non-Airport-Based Other 

Non-Hotel-Based 

Resident Airport Resident Airport 

Visitor Airport 

Airport-Based Business 

Airport-Based Other 

Vistor Airport 

Two distinct types of visitor travel or travelers can be identified based on the values-oftime: travelers with very high values-of-time and travelers with “normal” values-of-time. 

The low value-of-time suggests that the trips are made at a more leisurely pace with 

travelers being less willing to substitute higher cost and fast modes for lower cost and 

slower mode. The airport trips are also associated with low values-of-time for several 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 71 

reasons, such as the value-of-time for airport trips is in the range for noted for residentbased trips. 

Mode Choice and Transit Assignment Validation Results

Table 4 summarizes the observed and modeled linked transit trips and transit mode 

shares by trip purpose. The observed linked transit trips by purpose were estimated 

from the expanded 2001/2002 on-board transit travel survey data. Table 4 simply 

shows that the calibration process was successful in reproducing the observed targets. 

Table 5 summarizes the observed and modeled boardings by the path-building 

techniques defined previously. The modeled boardings per linked trip are higher than 

the observed boardings per linked trip. As discussed in the section describing pathbuilding parameters, the boardings per linked trip could be reduced by increasing the 

maximum walk access distances. When new on-board survey data are collected for the 

Las Vegas region, a concerted effort should be made to obtain good data on walk 

access and egress distances since reliable observed data could lead to improvements 

to the modeling process. 

Table 4: 2002 Observed and Modeled Transit Trips by Purpose

Trips Mode Shares Trip Purpose Observed Modeled Observed Modeled 

Home-Based Work 

 Low Income 17,920 17,896 29.8% 29.8% 

 Lower Middle Income 12,377 12,376 16.9% 16.9% 

 Upper Middle Income 5,303 5,303 2.9% 2.9% 

 High Income 3,599 3,599 0.8% 0.8% 

 Total Home-Based Work 39,199 39,174 5.2% 5.2% 

Home-Based School 2,471 2,464 0.7% 0.7% 

Home-Based Shop 9,304 9,275 2.1% 2.1% 

Home-Based Other 33,820 33,810 1.8% 1.8% 

Non-Home-Based 11,558 11,486 0.9% 0.9% 

Total Resident Trips 96,352 96,209 2.1% 2.1% 

Hotel-Based Convention / Business 257 257 0.4% 0.4% 

Hotel-Based Gaming 5,994 5,948 4.1% 4.1% 

Hotel-Based Other 3,343 3,338 2.2% 2.2% 

Non-Hotel-Based 3,308 3,302 1.9% 1.9% 

Airport-Based Resident 0 51 0% 0.4% 

Airport-Based Visitor 85 85 0.1% 0.1% 

Total Visitor Trips1 12,987 12,981 2.1% 2.1% 

Total Trips 109,339 109,190 2.1% 2.1% 

1

 Includes resident-based airport trips. 
 72 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Table 5: 2002 Observed and Modeled Transit Boardings by Path Set

Boardings Boardings / Trip Trip Purposes Path-Set

Observed Modeled Observed Modeled 

Home-Based Work 

 Low & Lower Middle Income 1 41,833 51,300 1.39 1.69 

 Upper Middle & High Income 2 11,673 16,521 1.32 1.86 

Home-Based Non-Work1 3 59,331 71,336 1.31 1.57 

Non-Home-Based & 

Visitor – Low Value-of-Time2 4 18,608 23,344 1.25 1.56 

Visitor – High Value-of-Time3 5 11,299 13,692 1.19 1.43 

Total Boardings 142,744 176,194 1.31 1.61 

1

 Includes home-based school, home-based shop, and home-based, other trips. 

2

 Includes hotel-based other, airport-based resident and airport-based visitor trips. 

3

 Includes hotel-based convention/business, hotel-based gaming, and non-hotel-based 

trips. 

.

0

5,000

10,000

15,000

20,000

25,000

30,000

0 5,000 10,000 15,000 20,000 25,000 30,000

Observed Boardings

Modeled Boardings

Local

Limited

Express

Figure 7: Assignment of Modeled 2002 Transit Trips vs. Observed Boardings by 

Route
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 73 

0

5,000

10,000

15,000

20,000

25,000

30,000

0 5,000 10,000 15,000 20,000 25,000 30,000

Boardings from Assigned Observed Trips

Modeled Boardings

Local

Limited

Express

Figure 8: Assignment of Modeled 2002 Linked Trips vs. Assignment of Observed 

2002 Linked Trips by Route 

Figures 7 and 8 compare the modeled and observed boardings on a route-by-route 

basis. Figure 7 compares the assignment of the modeled trip tables with the observed 

boarding counts from 2002. Figure 8 compares the assignments of the modeled trip 

tables to the assigned observed trip tables summarized from the 2002 on-board survey. 

The information in the above tables and the following figures suggest that the modeling 

process is reasonably reproducing observed travel 

Table 6 summarizes assignment statistics comparing the observed boardings with the 

assignment of the observed trip tables summarized from the 2002 on-board survey and 

the assignment of the modeled trip tables. 

Table 6: Transit Assignment Summary 

Trip Tables Assigned Measure Observed 

Boardings Observed Modeled 

Number of Linked Trips 109,339 109,339 109,190 

Total Boardings 142,744 150,360 176,194 

Boardings per Linked Trip 1.31 1.38 1.61 

Boardings by Type of Service 

 Local Bus 139,836 147,412 170,743 

 Limited Bus 2,320 2,642 3,878 

 Express Bus 588 306 1,572 
 74 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

MODELING PREMIUM TRANSIT AND DRIVE ACCESS TO 

TRANSIT

Premium Service Descriptions

Two new transit services were initiated in the Las Vegas region in 2004: The MAX 

service connecting the Downtown Transit Center with Nellis Air Force Base via North 

Las Vegas Boulevard was opened on June 30, 2004. The Strip Monorail service was 

opened between the MGM Grand Hotel and Casino on Tropicana and the Sahara Hotel 

and Casino on July 15, 2004. These two new services provided a unique opportunity to 

test the ability of the transit processing procedures and calibrated mode choice models 

to properly model new transit services. 

Premium Service Calibration Process

Since detailed transit trip purpose or origin-destination data were not available for the 

services, the specification of the correct nesting structure and alternative specific 

constant was developed by running the following tests and comparing the resulting 

boardings to observed boardings for the late-2004 through early-2005 time period: 

• Both services were coded and modeled as local transit services with no special 

treatment other than correctly specifying speeds, headways, and fares. 

• Both services were coded as above but were modeled as premium transit services, 

including separate transit path-building and mode choice; the “local service” 

alternative specific constants were used. 

• Both services were coded as above but were modeled as premium transit services, 

including separate transit path-building and mode choice; “premium service” 

alternative specific constants were specified via trial and error to best match 

boardings. 

Premium Service Path-Building and Modeling Procedures

The same basic path-building parameters for local transit paths were used. Fare 

weights for local bus use were used when premium paths were built. Fares for local 

buses were set as $5.00 boarding fares with additional $5.00 transfer fares between 

local buses. In contrast, boarding fares for premium transit modes were set to the 

proper values (i.e. $0.99 in 1995 dollars for the MAX and $2.39 in 1995 dollars for the 

monorail). Transfers to or from premium transit routes were free. Premium transit fares 

were also adjusted after the premium path-building to remove the artificially high local 

bus boarding and transfer fees. 

Also, the skims from the premium-only paths are compared to the skims using premium 

and local service and the “best” impedances are used for mode choice. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 75 

Premium Service Calibration Results

The modeling of MAX and monorail as premium transit services was determined to be 

the desirable approach. A number of iterations of the calibration process were made 

with different values for the premium alternative specific constants and with the pathbuilding procedures. A reasonable calibration was obtained for the MAX boardings with 

no difference between the values of the constants used for local and premium service. 

The alternative specific constants for walk to local and walk to premium transit show 

that there is no difference between the local and premium constants for each trip 

purpose. 

Figure 9 and Table 7 compare the modeled and observed boardings on a route-by-route 

basis for 2004/2005. The validation to the 2004/2005 provides two benefits: 

• Validation of the premium transit modeling 

• Validation for a year other than the year used for model calibration 

Figure 9 can be compared to Figure 7 for a qualitative comparison of the match 

between modeled and observed transit boardings by route for the original 2002 and the 

2004/2005 validations. With the exception of the underestimation of the Monorail, the 

two figures show similar patterns for the modeled versus observed trips. 

0

5,000

10,000

15,000

20,000

25,000

30,000

0 5,000 10,000 15,000 20,000 25,000 30,000

Observed 2005 Boardings

Modeled Boardings

Local

Limited

Express

Premium

Figure 9: Assignment of Modeled 2004/2005 Transit Trips vs. Observed Boardings 

by Route 
 76 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

The match between the modeled and observed ridership in two corridors is important in 

the determination of the validity of the models. Specifically, the reproduction of the 

transit ridership in the North Las Vegas Boulevard corridor demonstrates the ability of 

the model to estimate ridership on premium services while the reproduction of transit 

ridership in the Strip Corridor is crucial in showing the reproduction of ridership resulting 

from the visitor market. In total, observed transit ridership in the corridor is quite 

reasonably reproduced. 

In December 2005, ridership on the Deuce was just under 50,000 boardings per day 

and stabilized around 35,000 to 40,000 per day in early 2006. The ridership on the 

Deuce demonstrates the volatility of transit ridership in the Strip corridor. The model 

results suggest the need for a premium transit alternative specific constant representing 

substantial travel time savings. 

The results obtained for the MAX, the Strip Corridor, and the Monorail were all 

considered in making decisions regarding the final “validated” model for the region. 

While the MAX ridership was overestimated with no equivalent travel time savings for 

premium transit, ridership on the Monorail was substantially underestimated. It is very 

unlikely that Monorail will be considered in any of the alternatives to be considered for 

New Starts so the estimation of Monorail ridership becomes less important. 

Table 7 summarizes assignment statistics comparing the observed and modeled 

boardings. Results from the 2002 validation are also shown for a direct comparison of 

the model validation results for the two years. Table 8 summarizes the modeled transit 

trips and transit mode shares for 2002 and 2004/2005. The results shown in Table 8 

coupled with the validation results summarized in Table 7 suggest that the model is 

reasonably sensitive to changes in socioeconomic characteristics and transportation 

supply. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 77 

Table 7: 2004/2005 Transit Assignment Summary

2004/5 Results 2002 Results3 

Measure Observed Modeled Observed Modeled 

Number of Linked Trips1,2 112,791 112,791 109,339 109,190 

Total Boardings1,2 154,902 183,309 142,744 176,194 

Boardings per Linked Trip1,2 1.37 1.62 1.31 1.61 

Boardings by Type of Service 

 Local Bus 142,503 170,676 139,836 170,743 

 Limited Bus 6,139 5,443 2,320 3,878 

 Express Bus 600 1,597 588 1,572 

 MAX 5,660 5,593 – – 

 Strip Monorail 22,000 2,285 – – 

Coefficient of Determination (R2

)

 2 0.89 0.96 

Root Mean Squared Error on 

Boardings2 2,170 1,671 

Percent Root Mean Squared Error2 62% 50% 

1

 Actual number of linked transit trips for 2004/2005 is unknown. The modeled number of 

transit trips was assumed to be correct. 2

 The value excludes 2,285 assumed monorail trips (one trip per Monorail boarding) 

since Monorail ridership was estimated from information included in a press release 

rather than being based on actual passenger counts. The Monorail Company does not 

publish actual ridership data. 3

 Source: Table 10-18. 

Table 8: 2002 and 2004/2005 Modeled Transit Trips by Purpose

Modeled Trips Mode Shares Trip Purpose 2002 2004/2005 2002 2004/2005 

Home-Based Work 

 Low Income 17,896 18,519 29.8% 28.6% 

 Lower Middle Income 12,376 12,448 16.9% 15.8% 

 Upper Middle Income 5,303 5,026 2.9% 2.5% 

 High Income 3,599 3,271 0.8% 0.7% 

 Total Home-Based Work 39,174 39,264 5.2% 4.9% 

Home-Based School 2,464 2,477 0.7% 0.6% 

Home-Based Shop 9,275 9,631 2.1% 1.9% 

Home-Based Other 33,810 35,886 1.8% 1.7% 

Non-Home-Based 11,486 11,993 0.9% 0.8% 

Total Resident Trips 96,209 99,250 2.1% 1.9% 

Hotel-Based Convention / Business 257 461 0.4% 0.7% 

Hotel-Based Gaming 5,948 6,925 4.1% 4.2% 

Hotel-Based Other 3,338 4,116 2.2% 2.4% 

Non-Hotel-Based 3,302 4,054 1.9% 2.1% 

Airport-Based Resident 51 108 0.4% 0.8% 

Airport-Based Visitor 85 163 0.1% 0.2% 

Total Visitor Trips1 12,981 15,826 2.1% 2.3% 

Total Trips 109,190 115,076 2.1% 1.9% 

1

 Includes resident-based airport trips. 

Drive Access to Transit

Since there has been very little use of the facility for park-and-ride access to transit, as 

for the 2002 calibration year, drive access to transit could not be calibrated based on 

2004-2005 model results. Nevertheless, since future transit alternatives might make 
 78 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

use of park-and-ride access to attract choice riders, modeling procedures must be 

specified. 

The following summarizes modeling assumptions regarding the coding and modeling of 

drive access to transit: 

• Drive access will be coded only to formal park-and-ride lots. 

• Maximum drive access distances will be five miles to all park-and-ride lots except for 

end-of-line stations; at end-of-line stations, drive access of up to fifteen miles will be 

allowed. 

• Drive access distances and times will be determined from the coded roadway 

network. 

• For mode choice, drive access cost will be determined using the same cost per mile 

as for the auto mode. 

• Drive access will be modeled for all home-based trip purposes using the nesting 

structure shown in Figure 10-5; drive access will not be forecast for non-home-based 

trips. 

• Drive access to transit will not be forecast for non-resident trip purposes. 

• Drive access time will be considered as out-of-vehicle travel time for mode choice; 

for the home-based work purposes, the out-of-vehicle time coefficient is 2.0 times 

the in-vehicle time coefficient and for the home-based non-work trip purposes, the 

out-of-vehicle time coefficient is 3.0 times the in-vehicle time coefficient. 

The drive access to transit alternative specific constants have been estimated. The 

proposed regional fixed guideway system, including park-and-ride lots, was coded for 

the 2005 network. Two sets of forecasts were made: 

• A forecast allowing only walk access to transit was performed to provide estimates 

of transit ridership without park-and-ride. 

• A second set of forecasts allowing park-and-ride was performed. Park-and-ride 

constants were varied so that approximately 15 to 30 percent of the total premium 

transit ridership for each purpose was by auto access. 

Table 9 shows the target percentages of auto access by trip purpose along with the 

“calibrated” constants to achieve those percentages in the 2005 sensitivity test. The 

percentages shown in Table 9 should result in about 25 percent of all premium transit 

home-based work trips and about 15 percent of all premium transit home-based nonwork trips being made by auto access. In comparison, in the Denver region which has a 

very well developed park-and-ride system, approximately 45 percent of the total 

systemwide home-based work trips are made using auto access and about 30 percent 

of the home-based non-work trips are made by auto access. 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 79 

Table 9: Target Drive Access Percentages by Trip Purpose

Trip Purpose 

Target Drive 

Access 

Percent 

“Calibrated” 

Constant 

Equivalent Minutes of In-Vehicle 

Travel Time (Compared to Walk 

Access to Transit) 

Home-Based Work 

 Low Income 15% -0.65066 -104.4 

 Lower Middle Income 20% -1.15773 -97.7 

 Upper Middle Income 25% -2.55443 -89.6 

 High Income 30% -3.38720 -85.1 

Home-Based School 10% -4.05754 -153.1 

Home-Based Shop 15% -2.40336 -140.1 

Home-Based Other 15% -2.17282 -127.0 

MODELING HIGH-OCCUPANCY VEHICLE LANES

Modeling Issues

By design, the mode choice model includes the capability to estimate shared ride auto 

use by group size. Model constants were calibrated to reproduce observed two-person 

and three or more person shared ride auto use by trip purpose for 2002. The estimates 

of the observed two-person and three or more person shared ride auto use were based 

on the 1996 household survey data. 

Future highway alternatives might include the provision of high-occupancy vehicle 

(HOV) lanes. Experience elsewhere has shown that HOV lane users value the travel 

time saved through the use of HOV lanes more highly than the simple difference 

between travel time on the HOV lanes and on general purpose lanes. If HOV lane 

traffic volumes increase to the point where HOV lanes are experiencing congestion, 

modification of the minimum carpool size allowed to use the HOV lanes can be made to 

reduce the HOV lane delay caused by congestion. 

The original mode choice model included coefficients for HOV travel time savings. The 

HOV time savings variable, as specified, is applied to any HOV time savings in excess 

of five minutes. But the coefficients could not be rigorously calibrated since HOV lanes 

were non-existent in the region in 1996 (when the data were collected). As a result, the 

model coefficients were specified based on models developed in other regions. 

The problem with forecasting HOV lane use is similar to that encountered with 

forecasting drive access to transit. The FTA suggested that sensitivity testing of results 

is important whenever drive access to transit is modeled. The same advice is 

applicable to the forecasting of HOV lane use. Table 10 summarizes the results of such 

testing for the region. The travel model was used to forecast HOV shares and HOV 

lane use for 2030 for the following scenarios: 

• A no-build scenario where no HOV lanes were assumed to exist in the region. 

• The build scenario where an extensive HOV lane system was implemented for the 

region. 
 80 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

• The build scenario was modeled as above with the exception that the HOV time 

savings coefficient was applied to all increments of time saved, not just the 

increment in excess of five minutes. This was the most generous modeling 

approach for forecasting HOV travel. 

• The build scenario was modeled as above with the exception that the HOV time 

savings coefficient not used. This was the most restrictive modeling approach for 

forecasting HOV travel. 

The results summarized in Table 10 provide an idea of the sensitivity of the travel model 

to the HOV time savings coefficient. Since the coefficient cannot be rigorously 

calibrated, the sensitivity analysis as outlined above should be considered whenever 

planning and analysis of HOV lane alternatives is performed. In cases where HOV 

lanes are assumed to be in existence and an unrelated transit or roadway alternative is 

being analyzed, the model coefficient can be used as specified in Table 10. 

Table 10: HOV Time Savings Coefficient Sensitivity Testing

TRIPS BY MODE NOBUILD BUILD DIFFERENCE % CHANGE 

drive alone 5,197,452 5,197,383 (69) 0.0% 

shared ride 2 3,140,653 3,142,550 1,897 0.1% 

shared ride 3+ 2,754,531 2,755,983 1,452 0.1% 

walk to local transit 211,198 208,097 (3,100) -1.5% 

walk to premium transit 31,348 31,490 142 0.5% 

drive to transit 4,704 4,382 (322) -6.8% 

Total 11,339,885 11,339,885 (0) 0% 

T:\BETH\RTP 09-30\DOC\Model Methodology-Mode Choice Sections 2006-05-05 Pk2_v1.doc 

 
 APPENDIX 4 to the REGIONAL TRANSPORTATION PLAN 81 

APPENDIX 4- B 

NDOT TRAFFIC PROJECTIONS FOR THE RTC MODEL 

EXTERNAL TAZS 

Clark County External AADT's 2000-2030 

Source: NDOT Staff 

TAZ 

# Description 

2000 

AADT 

(total) 

2005 

AADT 

(total) 

2006 

AADT 

(total) 

2010 

AADT 

(total) 

2015 

AADT 

(total) 

2020 

AADT 

(total) 

2025 

AADT 

(total) 

2030 

AADT 

(total) 

 

1 US95, 5.9 mi N of SR156 (0030374) 5,200 5,450 5,550 6,250 7,000 7,700 8,500 9,300

 

2 US93, at MP LN-25 S 

of Alamo (0170001) 1,600 1,500 1,550 1,650 1,750 1,850 2,000 2,200

 

3 IR15, 2 mi S of Valley 

of Fire Intch (0030730) 17,000 21,700 22,100 25,400 30,000 34,000 38,000 42,000

 

4 SR157, .2 mi W of 

US95 (0030368) 2,750 2,700 2,750 3,500 4,200 4,700 5,800 6,500

 

5 SR147, .4 mi E of Los 

Feliz St (0030734) 3,000 2,600 2,750 3,500 4,200 4,700 5,800 6,500

 

6 

SR159, .1 mi E of rd to 

Red Rock Canyon 

(0030358) 2,850 4,550 5,300 6,400 8,000 9,800 11,500 13,000

 

7 

SR564, 1.7 mi E of Las 

Vegas Pkwy 

(0033200) 3,200 2,900 2,900 3,700 4,400 4,900 6,000 6,500

 

8 SR160, E of SR159 

(0030361) 8,750 9,550 9,750 12,000 15,000 17,000 19,000 21,000

 

9 

US93, .3 mi E of 

Boulder Beach Hwy 

(0035220) 12,900 13,000 13,000 18,000 20,000 22,000 23,500 25,000

 

10 US95, .1 mi S of RxR 

Pass Intch (0031014) 7,600 12,300 12,700 13,000 16,000 19,000 21,000 24,000

 

11 IR15, at the NV/CA 

line (0031110) 35,000 39,500 40,500 45,000 50,000 55,000 60,000 66,000
 82 REGIONAL TRANSPORTATION COMMISSION OF SOUTHERN NEVADA 

Source: Regional Transportation Commission Staff