PROJECT GOALS

Natural gas is a domestically available resource. The U.S. 

Department of Energy (DOE) supports natural gas vehicle and 

infrastructure research, development, and deployment through 

its FreedomCAR and Vehicle Technologies Program to help 

the United States reduce its dependence on imported petroleum and to pave the way to a future transportation 

network based on hydrogen. Natural gas vehicles can also 

reduce emissions of regulated pollutants compared with 

vehicles powered by conventional fuels such as gasoline 

and diesel. The goal of the Natural Gas Transit Users Group 

(TUG) is to facilitate the deployment of natural gas vehicle 

and infrastructure technology in transit fleets. 

NATURAL GAS TRANSIT BUSES

Transit buses are a key niche market for natural gas vehicles 

(Figure 1). Transit buses typically operate in heavily populated 

areas where pollution is a problem and residents are supportive 

of clean vehicle solutions. Transit vehicles are ideally suited to 

natural gas use for many reasons:

• Centrally located, fueled, and maintained 

• Serviced by a team of technicians who can be 

trained consistently 

• High fuel use, creating favorable economies of scale 

• Fixed routes with fixed schedules 

• Federally subsidized capital costs 

• High visibility and high impact. 

According to the American Public Transit Association (APTA), 

approximately 12% of transit buses were powered by natural 

gas as of 2004 (Figure 2). This proportion is expected to grow 

as more transit agencies switch to natural gas in response to air 

quality and energy security concerns. Approximately 25% of 

bus orders in 2004 were for natural gas vehicles, according 

to APTA.

THE NATURAL GAS TRANSIT USERS GROUP 

The TUG provides information and technical assistance to 

help transit agencies deploy and operate natural gas buses 

and infrastructure. Participation is intended for transit agency 

Assisting Transit Agencies with Natural Gas Bus Technologies

PROJECT IMPACT

Transit buses are a key niche market for natural gas vehicles.

Increasingly, transit agencies have been choosing natural gas 

buses as a way to cut air pollution and boost energy security. 

The Natural Gas Transit Users Group provides information 

and assistance to transit agencies that are operating or 

considering acquisition of natural gas transit buses. It is 

anticipated that this will lead to increased use of natural gas 

buses, resulting in reduced U.S. petroleum consumption. 

Figure 1. Liquefied Natural Gas Bus Operated by Arizona’s Valley Metro 

NREL/PIX 12534

Figure 2. Proportion of U.S. Transit Buses Powered by Natural Gas

Source: American Public Transportation Association
maintenance and operations staff, government agencies, and 

technology experts who provide specialized natural gas vehicle 

and infrastructure technical assistance. The TUG is led by 

DOE’s FreedomCAR and Vehicle Technologies Program, the 

National Renewable Energy Laboratory, and the Clean Vehicle 

Education Foundation.

The TUG typically meets once per year. The most recent 

meeting took place in November 2004 in Anaheim, California 

in conjunction with APTA’s Bus Equipment & Maintenance/

Procurement & Materials Management Workshop. Presentations covered the following topics:

• New Flyer natural gas transit buses

• FAB Industries natural gas bus fuel systems

• Bus idling practices

• Compressed natural gas cylinder inspection 

requirements

• Pressure relief device training tool

• Natural gas bus incidents

• Fuel supply in time of disaster

• Cummins Westport natural gas bus engines 

• John Deere natural gas bus engines.

By design, vendors and suppliers to the transit industry are 

admitted by special invitation only, during times when their 

technology or service is addressed by the group. There are no 

fees to attend TUG meetings (members pay their own travel 

expenses), and meeting proceedings are sent to members free 

of charge. 

SPECIALIZED SUPPORT 

TUG members can enlist the help of DOE’s Clean Cities 

Technical Assistance Teams (Tiger Teams) to solve specific 

problems (Figure 3). Handpicked by DOE and the National 

Renewable Energy Laboratory, this group of experts provides 

assistance related to the following problems: 

• Vehicle operations: vehicle performance or drivability, 

safety, maintenance, driver acceptance, specialized 

training needs, and implementation of alternative fuel 

vehicles at specific sites.

• Infrastructure operations: fueling station design, interaction with alternative fuel providers and fire safety code 

officials, fueling station performance and maintenance 

requirements, and operator training. 

Before asking for specialized help, requesting agencies 

typically must demonstrate that all appropriate efforts have 

been made at the local or regional level to solve the problems. 

DOE is especially interested in problems that suggest patterns 

of equipment failures or chronic service issues, because these 

may indicate industry-wide problems. For more information 

on Tiger Teams, visit www.eere.energy.gov/cleancities/

technical_assistance.html. Agencies requesting Tiger Team 

assistance must complete the same process identified for 

Clean Cities coordinators on this website.

CONTACTS AND RELATED WEBSITES

To join the TUG, or for more information, contact Hank 

Seiff at the Clean Vehicle Education Foundation, 

hseiff@cleanvehicle.org. TUG members receive e-mail 

updates and newsletters as well as access to TUG meeting 

proceedings. Also see the Clean Vehicle Education Foundation 

website at www.cleanvehicle.org. The TUG is affiliated with 

DOE’s Natural Gas Vehicle Technology Forum. For more 

information, visit www.nrel.gov/vehiclesandfuels/ngvtf. 

Send Questions or Comments to

Richard Parish

National Renewable Energy Laboratory

1617 Cole Blvd., MS 1633

Golden, CO 80401

Phone: 303-275-4453

Fax: 303-275-4415

E-mail: richard_parish@nrel.gov

Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific 

commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States 

government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.

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Operated by Midwest Research Institute • Battelle

DOE/GO-102005-2118 ■ April 2005

For more information contact:

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1-877-EERE-INF (1-877-337-3463)

www.eere.energy.gov 

A Strong Energy Portfolio for a Strong America

Energy efficiency and clean, renewable energy will mean a stronger economy,

a cleaner environment, and greater energy independence for America.

Working with a wide array of state, community, industry, and university 

partners, the U.S. Department of Energy’s Office of Energy Efficiency and 

Renewable Energy invests in a diverse portfolio of energy technologies. Printed with a renewable-source ink on paper containing at least 

50% wastepaper, including 20% postconsumer waste.

Figure 3. Tiger Teams Have Assisted the Washington Metropolitan Area 

Transit Authority with Natural Gas Bus and Infrastructure Challenges 

NREL/PIX 12293