C10
2171
A TECHNICAL REVIEW OF THE AIR-POWERED CAR
Caroline Baggott (cmb171) and Shawn McMullen (sjm95)
Abstract - This paper will investigate the feasibility of the
future use of air-powered cars as a means of greener
transportation. The mechanics behind the compressed air
powered pneumatic motor of this urban-based vehicle and
its environmental impacts will be evaluated compared to the
hybrid car, the electric-powered car, and the gasolinepowered car. Descriptions will cover how the efficiency,
fuel cost, and carbon footprint of the air-powered car
compares and contrasts to other environmentally friendly
cars, such as the hybrid and the electric car. This paper will
go into detail about how the technology behind the engine
makes the air-powered car ideal for urban transportation.
Emphasis will be put on how traffic patterns in Los Angeles
support the air-powered car as an urban vehicle, as well as
how the current market for air car production is focused in
overpopulated and underdeveloped cities in India. Overall,
the technology behind the air-powered car is feasible.
However, many issues related to its efficiency and
acceptance need to be addressed before it is available to the
general population. The significance of the air-powered car
is to decrease our reliance on and consumption of fossil
fuels and possibly eliminate their use in ground
transportation all together.
However, the current idea of using compressed air
technology in an air-powered car was created by former
Formula One engineer, Guy Nègre. While a number of
companies have done work with the design of an airpowered vehicle, Nègre’s company, Motor Development
International (MDI), has made the most progress in the
advancement of the air-powered car [3]. Indian car
manufacturing company, Tata Motors, has even signed a
deal with MDI to produce and distribute MDI’s air-powered
car [1]. However, personal air-powered cars are not yet seen
on any roads today.
The purpose of this paper, then, is to take a deeper look
into the air-powered car, analyzing the mechanics behind its
compressed air motor and its efficiency compared to other
alternative fuel vehicles, such as hybrid and electric cars
currently on the market as well as gasoline powered cars.
MECHANICS OF THE ENGINE
The air-powered car runs on a pneumatic motor that is
powered by compressed air stored onboard the vehicle.
Once compressed air is transferred into the onboard storage
tank, it is slowly released to power the car’s pistons. The
motor then converts the air power into mechanical power.
That power is then transferred to the wheels and becomes
the source of power for the car.
Under speeds of 35 mph, the air-powered car runs purely
on compressed air through the previously stated process.
Therefore it only emits cold air, making it emission free at
speeds less than 35 mph. However, once the air-powered
car accelerates beyond speeds of 35 mph, a small
conventional engine kicks in to heat the air. This heating
speeds the release of air to power the car’s pistons,
increasing the cars speeds [4]. Since this process requires
the use of a combustion engine and electricity to power the
onboard air compressor, the air-powered cars emissions
greater. This will be evaluated later in the paper.
The air-powered car is able to collect compressed air in
its onboard storage tank in two ways. One way is the car
can be electrically injected with compressed air directly into
its thermoplastic and carbon fiber tank. For this method to
be used, air stations similar to today’s gas stations will be
necessary. This process of refueling takes approximately
three minutes [4].
While there are obviously no air stations available in
today’s market for air-powered car fueling, Shiva Vencat,
Chief Executive of Zero Pollution Motor (ZPM), does not
see this as a downside. He claims that the economic
Invisible Hand will take care of that problem when the time
is right and air stations will be on the market when they are
needed [3].
Key Words – Air-Powered Car, Compressed Air Motor, Guy
and Cyril Negre, Tata Motors, Zero Emission Engine.
INTRODUCTION
In this time of immense fossil fuel dependency and
uncertainty of our environmental future, the exploration of
alternative, sustainable fuel sources becomes exceedingly
important, especially in the area of transportation. While
some examples of such vehicles can been seen on the road
now, such as the hybrid and electrics cars, greater innovation
is necessary. One such innovation that has been on the
drawing board for at least the past 20 years is the airpowered car.
The air-powered car is a vehicle that runs on compressed
air stored in an onboard, pressurized tank. While the use of
such a car may seem new, the idea for an air-powered car
has been around since the early 20th century when innovators
were working to come up with vehicle designs that could
compete with the popular horse and buggy [1]. Not only is
the idea of an air-powered vehicle dated, but also the
technology behind a compressed air car has been in use for
years. An example of this is stated in one article saying that,
“off-the-shelf technology already uses compressed air to
drive old-fashioned car engine pistons instead of combusting
gas or diesel fuel to create a burst of air” [2].
University of Pittsburgh
Twelfth Annual Freshman Conference
Swanson School of Engineering
April 14, 2012
1
Baggott
McMullen
The other method for refueling the air-powered car is by
plugging the car into a wall outlet. This allows the car’s
onboard air compressor to pressurize air surrounding the car.
This process takes approximately four hours [4].
Unlike gasoline, compressed air is not an energy source.
Compressed air is an energy storage medium similar to an
electric battery [1]. According to the authors of the article,
“Compressed Air Vehicles,” “Unlike other fuel types, which
store energy within the chemical bonds of the fuel,
compressed air derives its energy from the thermodynamic
work done by an expanding gas” [1]. The thermodynamic
work done by expanding gas in compressed air will be
explained later in the paper.
Where
XV, Xm = energy density per unit volume and mass,
respectively,
mT = tank mass;
R = universal gas constant;
T = temperature of gas;
M = molecular mass of gas [1].
Equations (2) and (3) show that in order to increase
volumetric energy density, an increase in tank pressure is
necessary. Similar to what was stated earlier, an increase in
tank pressure leads to greater inefficiencies in the expansion
process, limiting any benefits caused by the increase in
energy stored [1].
Energy Density of Compressed Air
Gas Expansion Losses
Compressed air has a very low energy density, especially
compared to the energy density of gasoline or electric
batteries. This means that a large volume onboard storage
tank is necessary to achieve a similar amount of energy
output compared to that of an average volume tank of
gasoline or an electric battery [5]. However, the small size
of the air-powered vehicle limits the amount of space
available for the onboard storage tank. This difficulty can be
addressed with the use of next-generation, high-pressure
tanks in air-powered cars. The current tanks used in air car
design are carbon fiber and can be pressurized to 5,100 psi.
These next-generation tanks can be pressurized to 10,000 psi
[1]. While this option of using modern tanks may seem
logical, higher tank pressure will lead to inefficiencies
caused by greater losses of energy due to gas expansion [1].
This will be explained in greater detail in the following
equations.
The energy that is contained by compressed air is in the
form of potential energy. This energy is equal to the amount
of work that can be produced when the air expands to
ambient pressure. The amount of energy can therefore be
found by (1) below, which shows the amount of energy
stored in the tank as a function of its volume and pressure.
ET = -pTVT ln (pA/pT)
As stated above, the thermodynamics of gas expansion
greatly reduces the available energy in compressed air. The
amount of energy lost through expansion depends on the
decompression of the air through one of two processes. The
first process, isothermal, achieves maximum efficiency of
100 percent when the temperature of the gas is held constant.
This process is recognizable through the very slow
expansion of the gas. The second process, adiabatic,
achieves minimum efficiency when no heat is transferred
within the system. This process is recognizable through the
rapid expansion of the gas [1]. As stated earlier, the airpowered car relies on the slow release of the compressed air
to power the car’s pistons. Therefore, the air-powered car’s
expansion process is isothermal when the car travels at
speeds under 35 miles per hour and does not rely on the
small combustion engine [6]. However, over speeds of 35
miles per hour when the air-powered car relies on a small
combustion engine to heat the compressed air and speed up
the release, the air-powered car’s expansion process is
adiabatic.
Equation (4) below is used to calculate the work done by
gas expansion. Based on (4) a gas expansion process is
isothermal when n=1. The process becomes closer to
adiabatic as the value of n increases until n=1.37, which
represents a perfectly adiabatic process.
(1)
Where
ET = tank energy,
VT = tank volume, and
PA, PT = ambient and tank pressures, respectively.
WE = pTVT (n/n-1) ((pA/pT)n-1/1 -1)
Where
WE = work done when gas expands,
pT = tank pressure,
VT = tank volume,
pA = ambient atmospheric pressure, and
n = the degree to which the expansion process is adiabatic
or isothermal [1].
However, “the energy embodied in compressed air itself can
be expressed independently of the storage tank, in the form
of energy density per unit volume or unit mass” [Papson,
Creutzig, Schipper]. This is shown in (2) and (3).
XV = (ET/VT) = pT ln (pT/ pA)
(2)
Xm = (ET/mT) = (RT/M) ln (pT/ pA)
(3)
(4)
Comparison to Other Alternative Fuel Cars
University of Pittsburgh
Twelfth Annual Freshman Conference
Swanson School of Engineering
April 14, 2012
2
Baggott
McMullen
While increasing the pressure of compressed air increases its
energy density, compressed air still does not carry as much
energy as gasoline or electric batteries. According to the
article “Compressed Air Vehicles,” “compressed air holds
only 0.5% of the energy in gasoline...” [1]. Electric batteries
used in electric cars, such as lead acid, nickel cadmium,
nickel metal hybride, and lithium ion, also have greater
energy densities than compressed air.
Even though
compressed air has greater energy by mass than electric
batteries, compressed air holds only 12 percent of the energy
in Lithium ion batteries [1].
Similarly, Mechanical engineering assistant professor at
Worcester Polytechnic Institute, James Van de Ven, said that
air compressors only recover 25 to 30 percent of the energy
used to compress the air, while the remainder of the energy
is lost [4]. This loss is attributed to heat, air leakage, and
other forms of waste. Van de Ven also said that the overall
efficiency of the air-powered car is nowhere near the 80
percent efficiency of hybrid-electric cars [4].
Therefore, one possibility for increasing the efficiency of
the air-powered car is by making it a hybrid vehicle that runs
on compressed air and some other energy source, such as
gasoline, diesel, or electricity.
FIGURE 1
“COMPARISON OF VEHICLE CARBON INTENSITY ACROSS ELECTRICITY
GENERATION SCENARIOS” [1].
This report from “Compress Air Vehicles” also showed
that the air-powered vehicle had the worst urban driving
range of the electrically powered Think City and gasolinepowered Volkswagen Fox. Because of the limited space on
the air-powered car and the low energy density of
compressed air, the air-powered car achieves only about 29
miles of travel on one tank of fuel. The gasoline-powered
Volkswagen Fox is able to travel about 408 miles on one
tank of fuel, and because of its efficiency, the electrically
powered Think City can travel about 127 miles on one
charge [1]. These results can be seen in Table 1.
Lastly, the report evaluated the air-powered car, the
Volkswagen Fox, and the Think City in terms of fuel cost
based on average 2007 prices.
Prices are based on 2007
prices because that was the time that the article was written
and the time that the designing of the air-powered car was at
its peak. At that time, the average cost of electricity was
$0.21/mi, and the average cost of gasoline was $2.80/gal.
This was equivalent to $0.09/mi for the Volkswagen Fox.
The results of this comparison can also be seen in Table 1.
This table shows that the cost of fueling the air-powered is
over twice as much as the cost of fueling a gasoline-powered
car such as the Volkswagen Fox. While gasoline is
obviously more expensive today, even if it costs $3.80/gal
today that would be equivalent to $0.12/mi for the
Volkswagen Fox. Therefore, even compared to today’s
prices, the fuel cost of the air-powered car is greater than the
gasoline-powered car [1].
ENVIRONMENTAL IMPACT
To evaluate the environmental impact of the air-powered
vehicle, one peer-reviewed article called “Compressed Air
Vehicles,” compared the air-powered vehicle to an urban
gasoline vehicle, the Volkswagen Fox, and an urban electric
vehicle, the Think City. The authors looked at each car’s
driving range, carbon footprint, and fuel cost. Since both the
air-powered car and the electric car rely on electricity, their
carbon emissions vary based on how the electricity used was
generated. However, the emissions of the gasoline-powered
car are constant at 11.3 kg CO2/gal [1].
The graph in Figure 1 shows the comparison of carbon
emission of all three vehicles, the air-powered car, the
electric car, and the gasoline powered-car, across different
electricity generating scenarios. The scenarios used in this
report were a low-carbon scenario of electricity generation
from natural gas, a high-carbon scenario of electricity
generation from coal, and an average scenario of electricity
generation based on a U.S. average fuel mix. Based on these
results, the air-powered car has the greatest carbon footprint
of all three vehicle types in any scenario of electricity
generation [1].
University of Pittsburgh
Twelfth Annual Freshman Conference
Swanson School of Engineering
April 14, 2012
3
Baggott
McMullen
TABLE 1
Figure 2 shows the typical velocity of cars for different
types of roadways [7]. Given this information, it is clear that
the air-powered car would be considered most
environmentally beneficial in local areas, such as cities,
because traffic patterns do not commonly break 35 miles per
hour.
Studies show that Los Angeles, California has the worse
traffic congestion of any other city in the entire nation. The
INRIX is a traffic services company that collects historical
and real-time traffic information. According to the INRIX,
commuters to Los Angeles, the second largest populated city
in the United States, waste eighty-six hours a year stuck in
traffic. During rush hour on the 110 North, the average
speed is only 6 miles per hour [8].
Figure 3 shows the speeds at which carbon dioxide
emissions are at their greatest. The graph shows that cars
release the most amounts of carbon dioxide emissions when
stuck in urban traffic and when exceeding speeds of 60 miles
per hour. This means that a single Los Angeles commuter
spends 86 hours a year releasing the highest amounts of
carbon dioxide possible from their car.
With the above facts in mind, the air-powered car seems
like an ideal choice for urban transportation because it would
be releasing nothing but clean air when stopped in urban
traffic. This being the case, it would be ideal for the airpowered car to be used in urban areas where the benefit of
zero emission release under thirty-five miles per hour can be
taken advantage of.
“PERFORMANCE CHARACTERISTICS OF CAVS VERSUS GASOLINE AND
ELECTRIC VEHICLES” [1].
URBAN-BASED VEHICLE
The main appeal of the air-powered car as an urban vehicle
is its 6-cylinder air-powered engine [4]. However, the airpowered car has the major drawback of running on pure air
power only at speeds up to 35 miles per hour, as mentioned
before. The car will then switch to a small conventional
engine that can run on various gases, such as gasoline,
diesel, or other fuels.
FIGURE 2
“TYPICAL VEHICLE VELOCITY PATTERNS FOR DIFFERENT ROADWAY TYPES
AND CONDITIONS” [7].
Current Market
Since the air-powered car’s engine is most beneficial to the
environment in urban areas, and it is still in early designing
stages, manufacturers have focused their production in
overpopulated, underdeveloped cities.
To date, the only automaker licensed to sell Nègre’s
technology is the India based, Tata Motors. Based on size
alone, Tata Motors is the eighteenth largest motor vehicle
manufacturing company in the world. As stated earlier in
this paper, the company bought the rights to the technology
in 2007 and made plans to mass-produce the air-powered
vehicles in Indian. Their plan was to later sell the
production rights to the United States for 15,000,000 dollars.
However, currently Tata focuses its sales in densely
populated and underdeveloped cities in India [2]. An
example of such a city is the Indian city of Mumbai.
Mumbai has the fourth largest population in the world, and it
is only surpassed in population density by other Indian
cities. Mumbai is also one of the most polluted cities in the
world.
As of August 2008, only 31 air-powered buses were
running in India as opposed to the 3812 diesel buses.
Considering the fact that air-powered transportation is a new
form of transportation, this may not be very surprising
information. However, 292 more diesel buses were put on
FIGURE 3
“EMISSION-SPEED PLOT OF INDIVIDUAL TRIPS OR TRIP SEGMENTS” [7].
University of Pittsburgh
Twelfth Annual Freshman Conference
Swanson School of Engineering
April 14, 2012
4
Baggott
McMullen
the road in a matter of seven months, while 6 air-powered
buses were taken off the road in the same time frame [9].
hybrid, and city and industrial transportation use slower
moving vehicles, the air-powered car could be beneficial if
assimilated into these areas.
Two companies that are currently looking into using the
air-powered car are Air France Industries and KLM
Engineering & Maintenance. These two companies are
trying to reduce their greenhouse gas emissions to meet AirFrance KLM Group’s environmental policy in order to
reduce ecosystem impacts [4].
The 2008 mayor of Paris, France considered the use of
the air-powered car for urban “rent-by-the-hour”
transportation. At this point, the mayor of Nice, France,
committed the city and its outlying regions to testing the airpowered car and possibly using them as car-rentals [11].
No major information on how the air-powered car has
been accepted in these two areas has been collected yet. If
the bus system in India is any indication of its growth, then it
probably did not progress very far.
In 2008, MDI developed the vehicle known as the
OneCAT. The basic three-seat model ended up costing the
consumer about 5000 dollars. The OneCat weighed 700
pounds or .35 tons, and had a zero-pollution urban range of
62 miles [12].
Even with environmentally friendly models, like the
OneCAT, the air-powered car has yet to become a wellestablished vehicle, and it continues to make up a small
portion of public transportation where it is found [13]. Since
the concept is not very deeply explored, it does not come as
a surprise that the air-powered car has just enough draw
backs to keep it on the side of the road and nearly out of
sight.
FEASIBILITY
With the reduction of air-powered public buses in India,
questions arise to whether or not the air-powered car will
ever become a feasible resolve to harmful fuel dependencies.
Are the vehicle’s mechanics and environmental impacts
enough to become a strong competitor with other
environmentally friendly cars, such as the hybrid and electric
car? Even if the air-powered car becomes a viable new form
of transportation, how well will it be incorporated into the
power craving style that is the American auto-industry?
Mechanics and Environmental Impacts
The main issue with the mechanics behind the air-powered
car is its efficiency. While the air-powered car emits no
harmful gases below speeds of 35 miles per hour, it can only
do this for 62 miles. This is because the energy density of air
is much less than that of fossil fuels and batteries.
Unfortunately, this problem cannot be solved by simply
increasing pressure, because this would only lead to
inefficiencies caused by greater losses of energy during gas
expansion [1]. Not only can the car not store as much energy
as a hybrid or electric car, but it also cannot recover as high
of a percent of the energy stored. The air-powered car can
only use 25 to 30 percent of the energy used to compress the
air, which is much less than the 80 percent efficiency of
hybrid-electric cars [4].
Tests run by KLM, a part of Air-France, also showed that
an air-powered car with a combustible fuel engine released
more greenhouse gases than an electric car. With batteries
being common in everyday life, research into making them
better is in high demand. Therefore, the electric car benefits
by having a larger scale of research being done on its fuel
source. However, thermodynamic technology has no real
push to better performance, so research behind the airpowered car rests solely on the designers of the air-powered
car [10].
Although the air-powered car is in fact feasible and could
one day compete with hybrid and electric cars as a method
of carbon footprint reduction, some major improvements
still need to be made. One method to improve the airpowered car would be to make it a hybrid with some other
fuel source. Even with these changes, it does not seem likely
that it will gain an advantage over either the hybrid or the
electric car [10].
American Market
While the market for the air-powered car seems to be
growing in popularity as an urban rental fuel saver, it has yet
to make an appearance on the roads in America.
According to an article by Motor Authority, the
American company Zero Pollution Motors (ZPM), which is
affiliated with MDI, planned to sell two models of the airpowered car in 2010. The CityCat and the OneCAT designs
were to go on sale, but seeing as they have not yet been on
the American market to date, something must have gone
wrong. It is possible that the air-powered car was viewed too
optimistically and recent information has stalled its
progression [13].
While the air-powered car has hit a wall in mass
production, it may hit an even bigger wall known as the
American consumer. Today American consumers want to be
“green” without having to give up the luxuries of their gaspowered vehicles and without paying an arm and a leg. With
a lighter design and large power loss compared to gasoline
powered engines and hybrids, it seems unlikely that the
current designs will be widely welcomed in America any
time soon. Considering it took the electric car almost 70
years after the first model was built to gain American
Urban Transportation
Since the air-powered car falls short to hybrids and electric
cars in efficiency, it would be better suited for urban or even
industrial areas. This is because speeds will remain low
enough for the car to release no harmful gases. Because the
buying price of the air-powered car is cheaper than any
University of Pittsburgh
Twelfth Annual Freshman Conference
Swanson School of Engineering
April 14, 2012
5
Baggott
McMullen
consumer attention, it is not likely that the air-powered car
will never make it in the American automobile market any
time in the near future [14].
[14] “Timeline: History of the Electric Car.” (2009, Oct. 30). PBS.org.
[Online]. Available: http://www.pbs.org/now/shows/223/electric-cartimeline.html
REFERENCES
[1]
Papson, Andrew, Felix Creutzig, and Lee Schipper (2010).
“Compressed Air Vehicles: Drive Cycle Analysis of Vehicle
Performance, Environmental Impacts, and Economic Costs.” Journal
of the Transportation Research Board. No. 2191. p. 67-74
[2]
“TATA Buys Rights to Make ‘Air-Powered Cars’ for Indian Market.”
(2008, Nov. 5). Asian News International. [Online Article]. Available:
http://www.lexisnexis.com/hottopics/lnacademic/?shr=t&csi=282802
&sr=HLEAD (TATA+BUYS+RIGHTS+TO+MAKE+%27AIRPOWERED+CARS%27+FOR+INDIAN+MARKET)+and+date+is+N
ovember,%202008
[3]
Ferguson, Wm. (2008, Apr. 20). “The Compressed-Air Car.” New
York Times Magazine. p. 71
[4]
Strumpf, Dan. (2009, May 31). “Entrepreneur believes air-powered
cars will fly Zero Pollution Motors weathers experts' criticism.” The
Houston Chronicle. p. 4 [Online Article]. Available:
http://galenet.galegroup.com/servlet/BCRC?srchtp=adv&c=1&ste=31
&tbst=tsVS&tab=2&aca=nwmg&bConts=2&RNN=CJ200969565&d
ocNum=CJ200969565&locID=upitt_main
[5]
Liu, Lin and Yu, Xiaoli. (2008). “Practicality Study on Air-Powered
Vehicle.” Higher Education Press and Springer-Verlag. [Online
Article]. Available:
http://www.springerlink.com/content/721r7419j51104m7/
[6]
Greenberg, Lisa. (2002, Dec.). “Compressed Air Becomes Latest
Alternative ‘Fuel’.” Automotive Body Repair News. vol. 41. p. 98
[7]
Barth, Matthew and Boriboonsomsin. (2009, Fall). “Traffic
Congestion and Greenhouse Gases.” ACCESS. p.2-9 [Online Article].
Available:
http://www.uctc.net/access/35/access35_Traffic_Congestion_and_Gre
nhouse_Gases.shtml
[8]
Gleeson, Gene. (2010, Feb. 23). “Study ranks L.A. as most congested
in U.S.” Los Angeles News. [Online Article]. Available:
http://abclocal.go.com/kabc/story?section=news/local/los_angeles&id
=7292591
[9]
“Mumbai Traffic Stats; Statistics for Reference on Transportation in
Mumbai.” (2009). Mumbai Environmental Social Network. [Online].
Available: http://www.mesn.org/mumbai%20traffic%20stats.html
ADDITIONAL SOURCES
“An Air-Powered Car by 2009? Don’t Hold Your Breath.” (2008, Feb. 27).
The New York Times. [Online]. Available:
http://wheels.blogs.nytimes.com/2008/02/27/an-air-powered-car-by-2009/
Clark, Amy. (2009 Apr. 14). “Voila! A Car Powered by Air.” CBS News.
[Online]. Available:
www.cbsnews.com/stories/2006/10/28/tech/main2135518.shtml
Ryan, Lisa and Turton, Hall. (2007). Sustainable Automobile Transport.
Northampton, MA: Edward Elgar Publishing, Inc. p. 23-52, 92-98, 227-253
Sperling, Daniel and Gordon, Deborah. (2009). Two Billion Cars: Driving
Toward Sustainability. New York, NY: Oxford University Press, Inc. p.
151-179
ACKNOWLEDGMENTS
We would like to give special thanks to our grader, Janine
Carlock, our Chair, Andrew Deao, our Co-Chair, Stephanie
O’Neill, and our advisor, Beth Newborg for their help with
this paper.
[10] “KLM Testing MDI AirPod Compressed Air Cars at Schiphol; UC
Berkeley Study Finds Compressed Air Cars Significantly Less
Efficient than Battery Electric Vehicles.” (2009, Dec. 13). Green Car
Congress. [Online Article]. Available:
http://www.greencarcongress.com/2009/12/klm-mdi-20091213.html
[11] Fairley, Peter. (2009, Nov.). “Deflating the Air Car.” IEEE Spectrum.
[Online Article]. Available:
http://spectrum.ieee.org/energy/environment/deflating-the-air-car/0
[12] “Air Car Models of the CATvolution.” AirCarCATvolution. [Online].
Available: http://aircarcatvolution.com/air-car-model/onecat-eng.php
[13] Ireson, Nelson. (2008, Feb. 21). “Tata-backed air-powered car in U.S.
by 2010.” Motor Authority. [Online Article]. Available:
http://www.motorauthority.com/news/1025098tata-backed-airpowered-car-in-u-s-by-2010
University of Pittsburgh
Twelfth Annual Freshman Conference
Swanson School of Engineering
April 14, 2012
6