1

DRAFT

COST-EFFECTIVENESS OF A 40% BODY AND CHASSIS 

WEIGHT-REDUCTION GOAL IN LIGHT-DUTY VEHICLES

Sujit Das

Energy and Transportation Science Division

Oak Ridge National Laboratory

Prepared for 

Lightweight Materials

Office of Vehicle Technologies

U. S. Department of Energy

June 2009

OAK RIDGE NATIONAL LABORATORY

Oak Ridge, Tennessee 37831

managed and operated by

UT-Battelle, LLC

for the

U.S. DEPARTMENT OF ENERGY

under contract No. DE-AC05-00OR22725
1

Cost-Effectiveness of a 40% Body and Chassis Weight-Reduction Goal 

in Light-Duty Vehicles

Oak Ridge National Laboratory

June 2009

1. Background

With the recent higher gasoline prices, new emission and fuel economy regulations that 

require by 2016 a 30% reduction in CO2 and other emissions and an average fuel 

economy of at least 35 mpg, the pressure to lightweight vehicles is stronger than ever 

before. The next few years will see considerable light-weighting across the automotive 

industry. Vehicle lightweighting represents one of several design approaches automakers 

are currently evaluating to improve fuel economy. Lightweighting is typically

accomplished by downsizing, integrating parts and functions, substituting materials, or by 

combining these methods. Lightweighting Materials’ (LM’s) component of the U.S. 

Department of Energy’s Vehicle Technologies program focuses on the development and 

validation of advanced materials and manufacturing technologies to significantly reduce 

automotive passenger vehicle body and chassis weight without compromising other 

attributes such as safety, performance, recyclability, and cost. The specific goals of LM

are to develop material and manufacturing technologies by 2010 that, if implemented in 

high volume, could cost-effectively reduce the weight of passenger-vehicle body and 

chassis systems by 50% with safety, performance, and recyclability comparable to 2002 

vehicles. In order to achieve this long-term weight-reduction goal, LM has set annual 

intermediate weight-reduction goals, starting with 10% in FY2007, and finally achieving 

50% by FY2010. This paper is a follow-on to an earlier study which focused on the 25% 

body and chassis weight-reduction goal of FY2008 (Das 2008). The present study

emphasizes the assessment of cost-effectiveness to achieve the desired goal of 40% body

and chassis weight reduction in FY2009.

To achieve its long-term weight-reduction goal, LM has prioritized its research areas in 

several lightweighting materials including advanced high-strength steel, aluminum, 

magnesium, titanium, and composites. Composites include metal-matrix materials and 

glass- and carbon-fiber reinforced thermosets and thermoplastics. Over the past several 

years, the LM R&D portfolio has included assessments of various lightweight body and 

front-end structures, such as those constructed of advanced high-strength steel, 

composite-intensive, and magnesium. These assessments, either completed or underway,

include, for example, one in which the goal is to design, analyze, and develop the 

technology for a composite-intensive, body-in-white structure that achieves a minimum 

of 60% weight savings over steel. Additionally, the latest LM multi-material vehicle 

(MMV) project aims to synthesize and demonstrate these various lightweight material 

component options in a single vehicle. Cost remains one of the major obstacles to

successful market penetration of these various lightweight materials. Complete vehicle 

system-level cost estimation is essential since it captures the cost reduction potential due 

to both part integration and mass de-compounding effect. Today OEMs remain more 

focused on the vehicle’s retail price rather than on vehicle life cycle cost.
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This paper provides an assessment of the cost-effectiveness of a 40% body and chassis 

weight-reduction goal for FY2009.The cost-effectiveness of the proposed weightreduction goal is determined based on the vehicle retail and life cycle cost analysis of a

potential lightweight material substitution scenario in various body and chassis 

components to achieve the desired weight-reduction goal. Cost methodology and 

potential data sources for the analysis are then discussed. Cost data collected for various 

vehicle components considered for achieving the weight reduction goal are then 

discussed, as are the assumptions and methodology used. A discussion of the results of 

the cost analysis of the proposed scenario is then presented, followed by conclusions.

2. Approach

2.1 Scenario Development 

Cost-effectiveness of a 40% body and chassis weight-reduction goal was demonstrated 

based on a scenario analysis by focusing on a specific lightweight material type 

substitution at a major vehicle-component level. A representative mid-size vehicle, i.e.

Honda Accord, was considered as the baseline against which the cost-effectiveness of 

weight reduction goal was determined. Due to a significantly higher weight reduction 

goal, carbon fiber-reinforced polymer-matrix composites (carbon-FRPMCs) and 

aluminum were primarily considered for body and chassis applications. These two 

materials have the potential to achieve the desired weight-reduction goal. Only carbonFRPMCs offer the potential for greater than 50% reduction in the weight of body and 

chassis components while providing strength five times greater than steel for structural 

parts. Most applications of this material have been in high-end vehicles and race cars. 

Aluminum use in today’s light-duty vehicles is limited to about 325 lbs/vehicle, mainly in 

castings for the powertrain (engine block, cylinder head and transmission cases) and 

wheels, but aluminum use could be significantly greater with the addition of wrought 

aluminum that has a weight reduction potential range of 30-50% compared to 

conventional steel.

Table 1 shows the 40% body and chassis weight-reduction scenario for a mid-size 

passenger car considered in the cost-effectiveness analysis. The scenario focuses on a 

plausible specific lightweight material option (i.e., mainly carbon-FRPMC or aluminum) 

at the broad component category level based on its near-term market potential to achieve 

the desired overall body and chassis weight reduction goal. This scenario approach 

allows determination of cost-effectiveness at a vehicle level, the context important for the 

actual implementation and commercialization of the lightweighting materials 

technologies in the market place. Specific components considered under body and chassis 

vehicle subsystems are highlighted in Table 1 (in bold type). The potential weight 

reduction for each part also is given. Since most lightweight component options 

considered here are yet to be commercialized, the percentage weight reduction assumed 

in each case is based on the best estimated value available in the literature today. The 

definitions of various vehicle components are based on the Automotive System Cost 

Model (ASCM, discussed below) and are provided in Appendix A. 
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Table 1. Mid-Size 40% Body& Chassis Weight Reduction Scenario1

SYSTEM

Baseline 40% Weight Reduction Scenario

Technology

Mass 

(kg) Technology

Mass 

(kg)

Powertrain

Engine

V-6 3.0L DOHC 

AL/AL 197 V-6 3.0L DOHC AL/AL 192

Energy Storage Lead-Acid, Standard 19 Lead-Acid, Standard 18

Fuel System Gasoline, 17 gal 83 Gasoline, 17 gal 83

Transmission Automatic (L5) 81 Automatic (L5) 79

P/T Thermal Generic (car) 29 Generic (car) 29

Driveshaft/Axle Generic 77 Generic 74

Differential Generic 25 Generic 25

Exhaust System Generic 48 Generic 48

Oil and Grease Generic 15 Generic 15

Powertrain Electronics Generic 10 Generic 10

Emission Control 

Electronics Generic 10 Generic 10

Body

Body-in-White Midsize steel unibody 320 Carbon Fiber Polymer Composites (55% wt redn.) 144

Panels Stamped Steel 60 Carbon Fiber Polymer Composites (55% wt redn.) 27

Front/Rear Bumpers Sheet Steel 10 TP/Carbon Fiber (60% wt reduction) 4

Glass Conventional, 4 mm 40 Polycarbonate (25% reduction) 30

Paint

Solventborne, avg 

color 12 Solventborne, avg color 12

Exterior Trim Generic 10 ULSAB (35% wt. reduction) 7

Body Hardware Generic 10 Generic 10

Body Sealers and 

Deadners Generic 2 Generic 2

Chassis

Cradle Generic 35 Aluminum (45% wt. reduction) 19

Corner Suspension Generic 47 Aluminum (35% wt. reduction) 31

Braking System ABS 48 Aluminum (5.5% wt reduction) 45

Wheels and Tires Aluminum 15” 71 Magnesium 15" (40% wt. reduction) 59

Steering System Generic 27 Aluminum (5.5% wt. reduction) 26

Interior

Instrument Panel Generic 26 Generic 26

Trim and Insulation Generic 24 Generic 24

Door Modules Generic 28 Generic 28

Seating and Restraints Generic 66 Generic 66

HVAC Generic 22 Generic 22

Electrical 33 33

Final Assembly 40 40

Total Body & Chassis 

Weight

(% less than baseline)

692 415

(40%)

Total Vehicle Weight 1525 1237

 

1All weights in the table denote values after primary weight savings only.
4

2.1.1 Carbon-FRPMC

Application of carbon-FRPMC in automobiles is quite limited and occurs only in lowvolume niche vehicles today such as Formula 1 race cars, Mercedes-Benz McLaren SLR 

supercar, Mazda’s RX-8, Honda’s Legend sedan, Mitsubishi’s Pajero SUV, and Nissan’s 

latest GT-R super sports car. General Motors is using the Corvette ZR1 to study the 

feasibility of high-volume carbon-FRPMC parts, whereas Toyota is planning to use a 

body frame made of this material in its 1/X concept car that will offer the same interior 

space as the Prius hybrid but only weigh one-third as much. Most carbon-FRPMC

applications include drive shafts, spoilers, A-pillars, underbody structures, and various 

body panels for high-performance, low-volume cars. Three Japanese companies, i.e., 

Toray Industries, Teijin, and Mitsubishi Rayon, which control 70% of the global carbon 

fiber market, are aiming to pioneer mass production of this material for widespread use in 

cars. For example, Teijin who is planning to start supplying carbon-resin composites to 

automotive parts makers as early as 2010 via its subsidiary Toho Tenax, is aiming to first 

make engine undercovers for high-range sports cars and then move towards mass market 

models. Toray Industries has invested in a German developer of carbon-FRPMC parts for 

cars and trucks, and is planning to expand its sales for automotive applications to 

approximately $510 million by 2015, including ultimately mass-produce carbon-fiber 

parts mainly for Toyota. Honda and Nissan have similarly joined with Toray and 

Mitsubishi Rayon to research new, less-expensive carbon fiber for cars.

To achieve a significantly higher body and chassis weight reduction goal, this analysis 

considers carbon-FRPMC for three major body components as shown in Table 1. These 

three body components, body-in-White (BIW), panels, and front/rear, have been 

considered as the most suitable components application of this lightweight material since 

these components contribute more than 25% of total vehicle weight. Potential percentage 

weight reduction assumed for these components has been in the mid range of 55-60%, 

although expected weight reduction has been reported to be 45-80% compared to mild 

steel depending on specific automotive part application. For example, Focal Project 3 of 

the Automotive Composites Consortium (ACC)—a collaborative, pre-competitive R&D 

partnership of the three big OEMs and DOE—predicted a 66% BIW weight reduction 

with a total number of parts less than 20 by demonstrating the potential on a carbon fiber 

B-pillar (Iobst et al. 2007). Similarly, niche vehicles such as X-Power sports vehicles 

have demonstrated 70% weight reduction potential in body panels compared with steel

(Marsh 2006). On the other hand, the structural composite underbody targeted to be a part 

of the United States Automotive Material Partnership (USAMP) Multi-Material Vehicle 

(MMV) project has obtained only 29% weight reduction using carbon fabric for floors.

The project’s objective, however, was to capitalize on the material’s strength to optimize 

the crash performance rather than to reduce weight (Berger and Jaranson 2009). In fact, 

carbon-FRPMC is currently not under further consideration in the MMV project and a 

new project on carbon-FRPMC body structure to optimize the weight savings potential 

has been under consideration for near-term funding. Use of carbon fibers in Formula 1 

cars such as Mercedes McLaren SLR in monocoque design is 50% lighter than steel 

components (Marsh 2006), and a 48% reduction in BIW mass without doors has been 
5

considered for a composite monocoque using various combinations of carbon and glass 

fibers in one of the earlier studies (Mascarin et al. 1995).

2.1.2 Aluminum 

To achieve the desired 40% body and chassis weight reduction goal, aluminum

substitution was considered in several vehicle chassis components, as shown in Table 1, 

including corner suspension, cradle, braking system, and steering system. Aluminum 

(forged or cast) is desirable in vehicle chassis components because it reduces un-sprung 

weight of the suspension, thereby improving overall handling performance and ride 

comfort. The cradle is the component assumed to have the most weight reduction—

45%—among the components considered here for aluminum substitution. Aluminum 

penetration has been relatively high in steering knuckles, and a weight reduction in the 

range of 35-45% can be achieved by integrating multiple parts into a single unit. 

Similarly, aluminum control arms, with a weight reduction potential of 20-30% compared 

to steel, have a 20% market share today. Aluminum corner suspension substitution 

assumes here both aluminum control arms and steering knuckles, with a combined weight 

reduction potential 35%.

Aluminum use has been considered for brake actuators and steering wheel column, with 

an estimated weight savings potential of 30.5% and 43%, respectively (EEA 2007). 

However, in both cases, the substitution of a single component in the system achieves a 

relatively small weight reduction at the system level compared to the weight reduction 

achieved in the single part. The weight reduction potential in each system is assumed to 

be 5.5%. Although the wheels segment has seen consistent growth in aluminum use, it is 

anticipated that the more aggressive weight reduction goal will produce a shift from cast 

aluminum wheels to cast magnesium wheels, the latter offering a 40% weight reduction 

potential compared to cast aluminum wheels (EEA 2007). Like other lightweight 

materials, high production-volume cost has been the limiting factor that historically

limited automotive growth. To date, an average vehicle contains 10-12 lbs of magnesium, 

mostly as castings in the instrument panel beam, transfer case, steering components, and 

radiator support. There is a great need for development of wrought magnesium products 

and manufacturing processes to provide improved mechanical and physical properties, 

crash performance, and corrosion resistance before magnesium’s use in more critical 

body and chassis applications can be expanded. To achieve the total savings goal of 40% 

of the primary body and chassis weight, a 35% reduction in exterior trim weight has been 

assumed. This weight savings are consistent with the target weight for the PNGV-Class 

vehicle which has a target weight of around 1000 kg vehicle curb mass (ULSAB-AVC 

1999).

2.1.3 Secondary Weight Savings

The objective for the selection of lightweighting material options for various vehicle 

components (as discussed above) was to achieve the primary 40% body and chassis 

weight-reduction goal. However, consideration of secondary weight savings in body and 

chassis components is important because it takes into account the effect of primary
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savings on the powertrain, chassis, and body components. The cost-effectiveness of 

lightweighting options depends considerably on the secondary savings since those 

savings helps to reduce the overall effect of higher lightweight material cost. Powertrain 

resizing in secondary weight savings calculations allows comparisons of functionally

equivalent vehicle designs—a reduced vehicle weight requires a less powerful engine to 

achieve equivalent performance (i.e., acceleration, range etc.). Secondary weight savings 

have been estimated by ASCM, and those savings related to the two scenarios considered 

here are presented in Table 2 along with other estimated major parameters in the costeffectiveness analysis. Total secondary weight savings are estimated to be 49% of 

primary savings and depend on the number of vehicle components considered. Most of 

the secondary weight savings occur in the powertrain system and depend on the extent of 

powertrain downsizing assumed. Since the ASCM includes secondary weight savings 

only of major vehicle components (i.e., all chassis components and a few major 

powertrain and body components), the percentage total weight savings in this case is 

somewhat lower than another recent estimate (Malen and Reddy 2007).

Note: % values within parenthesis indicate savings with respect to baseline steel

With the consideration of secondary weight savings, total body and chassis weight 

savings are estimated to be 45.3% as shown in Table 2. There will be a decrease in 

powertrain weight with powertrain resizing, where engine power is estimated to decrease 

by 24%. The resulting vehicle weight reduction has been estimated to 28%. Fuel 

economy estimates have been based on a reasonable rule of thumb that each one percent 

reduction in weight should give a 0.66 percent improvement in fuel economy, after a 

vehicle has been fully redesigned to account for the reduced power demands of a lower 

mass. Combined vehicle fuel economy would increase from the baseline value of 23 mpg 

to 27.2 mpg with the 40% body and chassis weight-reduction goal. 

Table 2. Major Parameters Considered in the Cost-Effectiveness 

Analysis of the 40% Body and Chassis Weight Reduction Goal

Parameter Baseline

40% Body and Chassis

Weight Reduction Scenario

Primary Body & Chassis 

Weight Savings

NA 277 kg (40%)

Secondary Weight Savings

Body & Chassis NA 37 kg (5.3%)

Powertrain NA 98 kg

Total NA 135 kg

Body & Chassis Weight 692 kg 378 kg (45%)

Powertrain Weight 594 kg 485 kg (18%)

Engine Power 122 kW 93 kW

Final Vehicle Weight 1524 kg 1102 kg (28%)

Combined Fuel Economy 23 mpg 27.2 mpg

Vehicle Lifetime Operation 120,000
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2.2 Cost Estimation Methodology

As with the earlier study (Das 2008), this analysis employs the Automotive System Cost 

Model (ASCM), developed jointly by Oak Ridge National Laboratory and Ibis 

Associates, Inc. in collaboration with Argonne National Laboratory, to estimate the costeffectiveness of the 40% body and chassis weight-reduction goal. ASCM estimates the 

vehicle-manufacturing cost at a level of five major vehicle subsystems (powertrain, 

chassis, body, interior, and electrical) consisting of more than thirty-five components 

(some components have been shown in aggregate form in Table 1 before) based on the 

aggregation of several components under the definition of Uniform Parts Grouping 

(UPG) generally used by the automotive industry (as listed and defined in Table 1 and

Appendix A). Each component represents a specific manufacturing technology. Vehicle 

retail price based on the sum of manufacturing cost (i.e., costs of components and

assembly), overhead, and selling is added to vehicle operation costs for the vehicle life 

cycle cost estimation. The interrelationships among vehicle subsystems and their effect 

on vehicle manufacturing cost are addressed, allowing inclusion of the impacts of 

secondary mass and cost savings as well. Functional interrelationships have been 

developed for major chassis components to estimate secondary mass savings based on 

first principles of physics, and using semi-empirical and empirical information available 

from the literature today. The powertrain sizing routine in this model is based on the 

algorithm used in the Argonne National Laboratory’s (ANL) hybrid vehicle cost model 

(HEVCOST), where the power and mass projections of various powertrain components 

are based on component-specific power and efficiency values, with the capability to 

evaluate alternative hybrid electric vehicle configurations and performance strategies 

(Plotkin et al. 2001). The main objective of this model is to facilitate estimation of 

vehicle-manufacturing and life-cycle costs using a uniform methodology to allow 

comparison of alternative advanced technologies being considered for vehicles today. 

This cost model has been integrated into the vehicle performance model PSAT 

(Powertrain System Analysis Toolkit) developed by Argonne National Laboratory,

thereby facilitating instantaneous vehicle cost estimation based on the detailed powertrain 

component sizing estimates by PSAT. This cost model has been used in several studies 

for a comparative cost assessment of different powertrain and body-in-white options for 

advanced technology vehicles (Das 2004 and 2005; Rousseau et al. 2005).

Two types of overhead, i.e., OEM and dealer margin are added to the vehicle 

manufacturing cost to estimate vehicle retail price. The former is assumed to be fixed, 

while the latter varied with the vehicle manufacturing cost. Vehicle operation cost 

categories considered in the vehicle life cycle cost estimation include financing, 

insurance, local fees, fuel, battery replacement, maintenance, repair, and disposal. 

Financing, insurance, and local fees costs are dictated by the vehicle retail price, while 

the fuel cost is dictated by the vehicle’s fuel economy (estimates are shown in Table 2) 

and a gasoline price of $1.90/gallon, based on near-term price trends (EIA 2009). With 

the exception of maintenance and repair, all other operation cost categories vary with the 

two lightweighting scenarios considered here based on estimated vehicle retail price and 

fuel economy. Total life cycle cost is estimated as the net present value assuming total 
8

vehicle lifetime miles are 120,000—based based on average 10,000 miles driven annually 

and a vehicle life of 12 years—and a discount rate of 10%.

2.3 Component Cost Data

Component technology cost data used in the analysis are mainly based on the latest 

estimates developed by Ibis Associates, Inc. using results of the recent studies developed 

for the industry (Ibis 2008 and Ibis 2009a). One such recent study stems from the 

USCAR-ACC composite structure programs that have been involved in the detailed cost 

analysis of carbon-FRPMC body structures. Even detailed cost analyses can have 

limitations—in this case the limitation is that the program never developed a complete 

design or high production-volume-scale cost analysis for a fully functional BIW 

structure. Cost data for other components—those for which the technology remained 

unchanged—were the same as those in the original model, since our objective in this 

analysis is to determine the relative cost-effectiveness of the plausible lightweight 

scenario to achieve the desired weight reduction goal and not the absolute total vehicle 

cost. Note that component technology costs in ASCM are based on OEM costs and 

represented in terms of functional relationships such as component mass and power, 

based on the detailed cost analyses available in the literature.

Several recent USCAR-ACC composite structure programs have been used in order to 

extrapolate to a full BIW structure and panel system functionally equivalent to the carbon 

fiber scenario considered previously in ASCM. The ACC programs contributing to this 

analysis include the FP2-composite truck box, FP3-carbon fiber structures, the Composite 

Underbody program, and a recent fiber, preforming, and molding technology tradeoff 

study (Ibis 2007, 2009b; Berger and Jaranson 2009 and Boeman and Johnson (2002)). 

The truck box study evaluated a high volume composite design and process study

employing P4 preforming and SRIM molding. Similarly, the carbon fiber structures 

program demonstrated a 60% mass savings over steel for a molded carbon fiber 

composite, although this was a large pillar type component and not a full vehicle 

structure. The Underbody program examined a broad range of concepts, including 

random and fabric glass, carbon, and high modulus polypropylene (HMPP) reinforcement 

through sheet molding compound (SMC) compression, long-fiber injection (LFI), and 

direct long-fiber thermoplastic (DLFT) molding processes. The most recent ACC tradeoff 

study compared glass, carbon, and natural fiber composites produced through SMC, 

structural reaction injection molding (SRIM), and resin transfer molding (RTM), and 

evaluated design based on equivalent strength and stiffness. Mass savings on individual 

components relative to steel ranged from 37% to 70% depending on the tensile or 

modulus equivalency. As noted earlier, a mass savings of 55% has been assumed in our 

case of carbon-FRPMC body structure, i.e., BIW and panels. The production economics 

are based here on the recent studies using high production rate P4 preforming and SRIM 

molding, achieving production rates of 15 parts per hour. The carbon material pricing is 

based on current volume pricing estimates of $30.80/kg ($14/lb), rather than the 

optimistic $22/kg ($10/lb) used in some of the earlier studies, and $4.24/kg for 

polyurethane systems.
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The entire body structure and carbon SMC panel systems were modeled using IBIS 

Technical Cost Models and the new regression analyses have been conducted to establish 

updated cost relationships sensitive to production volume, mass, material price, piece 

count, and part area. Figure 1 shows the estimated cost sensitivity to annual production 

volume of carbon-FRPMC body-in-white structures for a mid-size vehicle. Estimated 

costs are based on the baseline BIW and panel mass of 128 kg and 42 kg, respectively, 

representing a 49% reduction in mass compared to the baseline steel body structures. As 

one would expect, carbon-FRPMC body structure is quite insensitive to annual 

production volume since it is a low-volume process: total part cost varies less than 

$20/part and is relatively constant at around $2,960/part beyond production volume of 

50,000 parts/year.

The cost sensitivity to annual production volume for body-in-white structures of various 

materials is shown in Figure 2. The costs represented in Figure 2 include the assembly 

cost. Cost graphs shown here are based on the baseline weight for a mid-size vehicle 

considered in the model and not the actual weight used in the analysis here. For example, 

baseline masses of body-in-white structure considered for steel, aluminum, and 

thermoset/glass composites (TS/glass composites) are 250 kg, 143 kg, and 202 kg, 

respectively. Current material pricing is as follows: steel $0.77/kg; aluminum sheet 

$3.31/kg; aluminum casting $2.86/kg; vinyl ester compound $4.24/kg; glass fiber 

$1.50/kg; and carbon fiber $30.80/kg (reflecting a recent surge in demand for large 

commercial jet aircrafts). Based on these material prices and masses assumed, the carbonFRPMC structure is more expensive than all other lightweight material options 

considered here, except at annual production volume of 10,000 parts, when the aluminum 

unibody is more expensive than carbon-FRPMC. The crossover between these two 

materials is estimated to occur between production volumes of 10K-25K. Unlike the 

current estimate, most past studies indicate cost parity of carbon-FRPMC with 

conventional baseline steel structure at a production volume in the range of 5,000-35,000 

(Kang 1998 and Fuchs 2008). Their estimates of cost parity are mainly due to their 

assumption of lower carbon fiber prices of $11-$17.50/kg, compared to this analysis’ 

assumption of $30.80/kg. Fuchs (2008) estimated cross-over point of 35,000 for the costeffectiveness of traditional steel and carbon composites represents 45% of car models and 

10% of all cars produced in North America in 2005. The cost sensitivities of steel and 

aluminum structures are quite similar to each other in terms of the curve slope, but they

are offset by the material price difference and some increased processing costs. As also 

has been observed earlier, the cost sensitivity curves for composite body structures (i.e., 

for both glass-FRPMC and carbon-FRPMC) are relatively flat compared to other 

materials. For our analysis, the threshold production volume of cost-effectiveness is

240K parts/year for baseline steel and 50K parts/year for the lightweight vehicle.
10

0

500

1000

1500

2000

2500

3000

3500

4000

0 50 100 150 200 250 300

Annual Production Volume (K)

Carbon-FRPM

C

Body Structure Cost ($/part)

Structure

Assembly

Panels

Total

Figure 1. Carbon-FRPMC Body Structure Cost Sensitivity to

Annual Production Volume

0

500

1000

1500

2000

2500

3000

0 50 100 150 200 250 300

Annual Production Volume (K)

Body-in-White Structure Cost ($/part)

Steel Unibody

Aluminum Unibody

TS/Glass Composite

CF Composite

Figure 2. Lightweight Material Body-In-White Cost Sensitivity to

Annual Production Volume
11

0

100

200

300

400

500

600

0.5 1 1.5 2 2.5 3 3.5 4 4.5

Al Casting Price ($/kg)

Part Cost ($)

Brake System

Steering System

Cradle 

Corner Suspension 

Base Price $2.86/kg

Figure 3. Aluminum Chassis Component Cost Sensitivity to Material Price

Figure 3 shows the per-part cost sensitivity to aluminum casting price for four different 

aluminum chassis components considered under the carbon-FRPMC scenario based on 

part weight used in a mid-size vehicle. Note that the part cost estimates for the base price 

of $2.86/kg for aluminum casting is also shown. The cost estimates for the aluminum 

cradle includes not only casting cost, but also melting, scrap recovery, machining, and 

corrosion protection. Cost estimates of aluminum braking and steering systems were 

made by adding the estimated cost of replaced aluminum component (e.g., brake 

actuators and steering wheel column for braking and steering systems, respectively) to 

the unchanged original balance of system cost made of conventional steel. Cost data for

replaced aluminum components are based on recent available estimates (EEA 2007). Cost 

relationships consist of two components, i.e., material and processing. As Figure 3 shows,

the higher weight of the corner suspension causes its cost to be higher and more sensitive 

than the cradle is to aluminum ingot prices. The sensitivity of steering and braking 

system costs to aluminum ingot pricing is not significant since the aluminum components

contributes less than 10% of total system weight in each case. Cost of cast magnesium 

wheels are based on 15” wheels and reflects current material pricing and processing 

technology improvements and also includes tire costs. It has been assumed to have 20% 

price premium compared to cast aluminum wheels (EEA 2007 and Long et al. 2005).

3.0 Results

Figure 4 shows the estimated cost savings resulting from the 40% body and chassis 

weight savings of the carbon-FRPMC scenario compared to the baseline, by major 

vehicle systems, vehicle retail price, and life cycle cost. Only three major vehicle systems 
12

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

1

C

ost Savings ($/vehicle)

Pow ertrain

Body

Chassis

Vehicle Retail Price

Operation

Life Cycle Cost

Figure 4. Estimated Cost Savings of 40% Body and Chassis

Weight Reduction Scenario

are considered because the cost of other vehicle systems—interior, electrical, and final 

assembly—are assumed to be the same under all scenarios. There would be 

$1490/vehicle increase in retail price level and a $1100/vehicle increase in life cycle cost. 

The increase in vehicle retail price is mainly due to the body system cost increase of

about $2200, the result of the higher cost of carbon unibody structure. The cost savings 

due to the downsizing of the powertrain and chassis is not sufficient to lower the vehicle 

retail price. In addition, with the consideration of quite a few operation cost categories 

(e.g., financing, insurance, and local fees) as functions of vehicle retail price and the 

assumption of lower gasoline price of $1.90/gallon – a 40% weight reduction goal cannot 

be achieved even at the level of life cycle cost. It is estimated that if the price of 

aluminum used in chassis components is reduced from the baseline price of $2.86/kg to 

$2.20/kg and carbon fiber price is reduced from the baseline price of $30.40/kg to DOE’s

long-term target value of $6.60/kg, the cost-effectiveness at the life cycle cost level could 

be achieved, even at the assumed gasoline price of $1.90/gallon. As one would expect, 

the cost-effectiveness of carbon-FRPMC vehicle would improve with higher fuel price as 

also shown here in Figure 5. It is estimated that if the fuel price increased from a baseline 

price of $1.90/gallon to about $4.25/gallon, cost-effectiveness could be achieved at the 

level of vehicle life cycle cost without requiring any material price reductions. It is 

anticipated that a combination of material price decreases and a fuel price increase would 

be necessary to achieve the cost-effectiveness of carbon-FRPMC vehicle at the level of 

vehicle retail price.
13

40000

42000

44000

46000

48000

50000

52000

1 1.5 2 2.5 3 3.5 4 4.5 5

Fuel Price ($/gallon)

Life Cycle Cost ($/Vehicle)

Baseline Steel

Carbon-FRPMC

Figure 5. Vehicle Life Cycle Cost Sensitivity to Fuel Price

4.0 Conclusions

Cost-effectiveness of ALM’s 2009 body and chassis weight reduction goal of 40% in 

light-duty vehicles was assessed based on the use of lightweight material options for 

various body and chassis components under a plausible mid-size vehicle scenario. The 

weight reduction goal here is very similar to that of the Japanese government whose 

intention is to mass-produce a cost-effective, recyclable carbon fiber and use it to achieve 

a 40% reduction in cars by the middle of the next decade (Brooke 2009). The lightweight 

material substitution options considered here focused on carbon-FRPMC for body

systems and aluminum for chassis components. Among potential lightweighting 

materials, carbon-FRPMC has the greatest weight savings potential. The analysis also 

considers the effect of primary weight savings of 40% on other vehicle components that 

can be resized while maintaining the same level of vehicle performance with the reduced 

vehicle weight. This weight savings are known as secondary weight savings. Due to 

consideration of secondary weight savings, total body and chassis weight savings are

estimated to be 45%, whereas the final vehicle weight savings of 28%. Cost-effectiveness 

of 40% body and chassis weight reduction goal is estimated in terms of both vehicle retail 

price and life cycle cost using the detailed 35+ component level automotive system cost 

model developed by ORNL and Ibis Associates, Inc. Cost data of components considered 
14

for lightweight material substitution are collected from recent major studies, thereby 

reflecting the latest technology developments and material prices.

Even with the consideration of powertrain resizing and secondary body and chassis mass 

savings, carbon-FRPMC lightweight material vehicle option is not cost-effective in 

meeting the ALM 40% body and chassis weight savings goal from the life cycle cost 

perspective if the recent low gasoline price trend continues. The higher cost results 

mainly from using the carbon-FRPMC body system which is $2200 more expensive than 

the baseline system. The higher cost is not offset during the vehicle operation stage. The 

higher vehicle retail price also affects some of the operation cost categories such as 

financing, insurance, and local fees which are functions of vehicle retail price. The 

vehicle retail price is estimated to be $1492 higher than baseline. The life cycle cost is 

$1102 higher. From the life cycle cost perspective, either a change in material price or 

fuel price would be necessary to achieve the cost-effectiveness goal. Aluminum and 

carbon fiber prices need to be at $2.20/kg and $6.60/kg, respectively, whereas fuel price 

needs to be $4.25/gallon for the lightweight vehicle to be cost effective. It is likely that a 

combination of material and fuel prices would be necessary to achieve the costeffectiveness at the level of vehicle retail price, which is the primary consideration of

OEMs for determining the viability of any new vehicle technology. The extent of the

necessary price changes would depend on the extent of secondary mass savings 

considered, with this analysis employing a conservative estimate of secondary mass 

savings. In contrast to this conservative estimate, General Motors 1992 Ultralite carbon 

body structure weigh 191 kg (compared to the 171 kg body structure in this analysis) 

demonstrated a super-lean 635 kg curb weight concept car—considerably lower than our 

estimated curb weight of 1102 kg. 

Findings in this analysis are consistent with the earlier findings that carbon-FRPMC is 

too expensive for large scale application in light-duty vehicles today. Composite 

monocoque BIW designs considered in the past several studies indicate cost to be in the 

range of 41-73% higher than the steel unibody, depending on the type of tooling used 

(Mascarin et al. 1995). The technology is suited for mainly low annual production 

volume, and a reduction in carbon fiber price would help to a large extent in improving 

its viability. Vehicle platforming considerations which allow low annual production 

volumes would facilitate the competitiveness of carbon-FRPMC body structure (Fuchs et 

al. 2008). Lightweighting also improves the cost-effectiveness of advanced technology

vehicles by lowering the expensive powertrain cost while maintaining the performance 

(Aluminum Association 2008, Brooke 2009, and Das 2005). Consideration of powertrain 

resizing, secondary mass savings, and life cycle cost perspectives would therefore be 

important to maximize the fuel economy gains from a lightweight structure and eventual 

successful market penetration of lightweight vehicles in the future. With a higher 

lightweighting goal, reduced material cost become more critical because it is such a large 

share of the total part costs particularly in low production volume production 

manufacturing processes. Accordingly, a current focus of DOE’s lightweight materials 

program is the development low cost carbon fibers from alternative cheap renewable 

resources and high-volume processing of composites.
15

REFERENCES

Aluminum Association (2008). “Aluminum Vehicle Structure: Manufacturing and 

Lifecycle Cost Analysis: Hybrid Drive and Diesel Fuel Vehicles,” Research Report 

No. 2008-05, written by Ibis Associates, Inc. for the Aluminum Association.

Berger, L. and Jaranson, J. (2009). “Automotive Composites Consortium Focal Project 

4,” FY 2007 Progress Report for Lightweighting Materials, Vehicle Technologies 

Program, U.S. Department of Energy, Washington, DC, Available at: 

http://www1.eere.energy.gov/vehiclesandfuels/resources/vt_lm_fy07.html, accessed 

on 5/22.

Boeman, R. G. Johnson, N. L (2002). “Development of a Cost Competitive, Composite

Intensive, Body- In-White,” SAE Paper No. 2002-01-1905, the Society of 

Automotive Engineers, Warrendale, PA.

Brooke, L. (2009). “A Featherweight Future,” Automotive Engineering International, 

Vol. 117, No. 5, May, pp. 24-26

Das, S. (2004). “A Comparative Assessment of Alternative Powertrians and Body-inWhite Materials for Advanced Technology Vehicles,” SAE Paper No. 2004-01-0573, 

the Society of Automotive Engineers, Warrendale, PA.

Das, S. (2005). “Lightweight Opportunities for Fuel Cell Vehicles,” SAE paper no. 2005-

01-0007, the Society of Automotive Engineers, Warrendale, PA.

Das, S. (2008). “Cost-Effectiveness of a 25% Body and Chassis Weight-Reduction Goal 

in Light-Duty Vehicles,” draft report, Oak Ridge National Laboratory, Oak Ridge, 

TN, Aug.

Energy and Environmental Analysis, Inc. (EEA) (2007). “Analysis of Light-Duty Vehicle 

Weight Reduction Potential,” draft final report submitted to the U.S. Department of 

Energy, Office of Policy, Arlington, VA, July.

Energy Information Administration (EIA) (2009). “Annual Energy Outlook 2009 with 

Projections to 2030, Updated Annual Energy Outlook 2009 Reference Case with 

ARRA, http://www.eia.doe.gov/oiaf/servicerpt/stimulus/excel/aeostimtab_12.xls 

accessed on 5/28/09.

Fuchs, E. R. H. Field, F. R. Roth, R. and Kirchain, R. E. (2008). “Strategic Materials 

Selection in the Automobile Body: Economic Opportunities for Polymer Composite 

Design,” Composites Science and Technology, Vol. 68, pp. 1989-2002.

Ibis Associates, Inc. (Ibis) (2007). “Technical Cost Model Development for a Structural 

Composite Underbody: Supporting USCAR-ACC Composite Structures Program,” 

Waltham, MA.
16

Ibis Associates, Inc. (Ibis) (2008). “Data Document: ORNL Automotive System Cost 

Model,” Waltham, MA, July 1.

Ibis Associates, Inc. (Ibis) (2009a). “Data Document: ORNL Automotive System Cost 

Model,” Waltham, MA, April 9.

Ibis Associates, Inc. (Ibis) (2009b). “Technical Cost Analysis & Model Development: 

Fiber and Process Preforming Alternatives: Supporting USCAR-ACC Composite 

Structures Program,” Waltham, MA.

Iobst, S. Berger, L. Fernholz, K. Dahl, J. and Smith G. (2007). “Fabrication of the

Automotive Composites Consortium Carbon Fiber B-Pillar,”International SAMPE 

Symposium and Exhibition (Proceedings), v 52, SAMPE’07: M and P – From Coast 

to Coast and Around the World, Conference Proceedings, 2007, 11p.

Long, S. Xu, S. and Cao, H. (2005). “Technical Economic Considerations for Production 

and Application of Mg Castings in China,” Materials Science Forum, Vols. 488-489, 

pp. 909-914, June.

Malen, D. E. and Reddy, K. (2007). “Preliminary Vehicle Mass Estimation Using 

Empirical Subsystem Influence Coefficients,” report prepared for the FGPC Mass 

Compounding Project Team, Auto/Steel Partnership, Southfield, MI, May 9.

Marsh, G. (2006). “Composites Conquer with Carbon Supercars,” Reinforced Plastics,

Jan., pp. 20-24.

Mascarin, A. E., Dieffenbach, J. R. Brylawski, M. M. Cramer, D. R. and A. B. Lovins

(1995). “ Costing the Ultralight in Volume Production: Can Advanced Composite 

Bodies-In-White Be Affordable?,” paper presented at the 1995 International Body 

Engineering Conference & Exposition, held on Oct. in Detroit, MI.

Plotkin, S. et al. (2001). “Hybrid Vehicle Technology Assessment: Methodology, 

Analytical Issues, and Interim Results,” Argonne National Laboratory Report 

ANL/ESD/02-2, Argonne, IL.

Rousseau, A. Sharer, P. and Das, S. (2005). “Trade-off between Fuel Economy and Cost 

for Advanced Vehicle Configurations,” presented and published at EVS21conference, 

held in Monaco, Apr. 2-5.

Ultra light Steel Autobody – Advanced Vehicle Concepts (ULSAB-AVC) (1999). 

“Description of ULSAB-AVC Benchmarking and Target Setting,” Southfield, MI. 

Nov. 18.
17

Appendix A

ASCM Vehicle Component Definition

ASCM UPG ASCM Description

Group Name

Powertrain Engine 30A Base Engine In this model, 'engine' refers to conventional heat 

engines. In addition to basic powerplant and auxiliary 

systems and components, engine cooling systems, 

lubrication, fluid containers and pumps are also included.

30B Other Engine 

Components

Fuel Cell n/a Fuel Cell Power System

Generator n/a The APU or power converter for parallel and series 

hybrids.

Motor n/a The electric motor, including power cables.

Controller/

Inverter

n/a The power controller/phase inverter system

Energy 

Storage

36K01 High Voltage 

Battery

The primary electrical energy storage device or package. 

Maybe a single battery or module of linked cells.

Fuel System 36F Fuel Tank and 

Lines

Fuel tank, gauge, tank shield, access door, mounting 

straps, fuel pump.

37B Fuel 

Transmission 36E G Transmission In this model the transmission refers to the gearbox only. 

Note that in some literature, "transmission" refers to the 

clutch, gearbox, driveshaft, and differential. These are 

each treated as separate components/subsystems in this 

model.

36C Clutch and 

Controls

Supplied as a single assembly, a releasable coupling that 

transmits torque from the engine to gearbox.

Driveshaft/

Axle

31 Final Drive A single assembly that couples with the gearbox and 

differential

31 Final Drive An assembly of the axle shaft, housing, boots, and 

couplings to the wheels

Differential 31 Final Drive Transmits energy from driveshaft to axles and allows for 

differential speed of each wheel.

P/T Thermal Cooling module (radiator, fan assembly etc)

Exhaust 

System

36E

36O

Exhaust System

Catalytic 

Converter

All exhaust equipment after the manifold; pipe: catalytic 

converter, muffler.

Powertrain 

Electrical

30C Engine Electrical Engine control wiring, sensors and processors. The 

controller for electric motors for HEVs may be considered 

as part of the electric motor, or could be included here, if 

desired. Low voltage used for accessory power is also 

included here.

Emission 

Control 

Electronics 30C10

Engine Emission 

Controls

The sensors, processors, and engine feedback 

equipment that maintain emissions within specified 

parameters.

Oil and 

Grease

37B Oil and Grease Engine oil, transmission oil, miscellaneous lubricants
18

ASCM UPG ASCM Description

Group Name

Body BIW 11A-11B Body in White and 

closures

The Body-In-White is the primary vehicle structure, 

usually a single-body assembly, consisting of engine 

compartment, passenger cabin, and storage. Closure 

panels (including hinge mechanism) and hang-on panels 

(such as fenders) are included, even if non-structural. In 

this model, doors are included as well.

Front/Rear 

Bumper

36G Fenders

Glass 18 Glass Front and rear windshields, door window glazing

Paint

22 Paint and Coating Includes the cost and mass of the total painting operation; 

e-coat, priming, base coats, color coats, clear coats.

37A, C, D Paint

Exterior 

Trim

14, 20 Molding and 

Ornaments

Bumper cover, air deflectors, ground effects, side trim, 

mirror assemblies, nameplates

Body 

Hardware

Door window mechanism, wipe/wash, defog/deice, door 

latch mechanism

Body 

Sealers & 

Deadeners

Self-explanatory

Chassis Cradle 32 Frame A front sub frame that bolts to the BIW and supports the 

mounting of the engine

Corner 

Suspension

33 Suspension Upper and lower control arms, ball joints, spring, shock 

absorber, steering knuckle, stabilizer shaft

Braking 

System

35 35D Brakes Hub, disc, bearings, splash shield, and calipers.

Wheels and 

Tires

36A 36C Wheels, Tires, and 

Tools

Self explanatory. Tools determinant by type of tires 

featured.

Steering 

System

34 Steering A complex system from the steering wheel, column, 

joints, linkages, bushes, housings and potentially 

hydraulic or electric assist equipment.

Interior Instrument 

Panel

21 Trim and 

Insulation

The instrument panel module consists of an underlying 

panel structure, knee bolsters and brackets, the 

instrument cluster, exterior surface, wiring, console 

storage, glove box panels, glove box assembly and 

exterior, and a top cover.

Trim and 

Insulation

15,17,21 Headliner Headliner is actually the overhead system containing 

acoustical sound absorption, assist handles, coat hooks, 

modular headliner assemblies, overhead console 

assemblies, small item overhead storage, pillar trim, sun 

visors and retainer.

Center Console Emergency brake cover, switch panels, ash trays, arm 

rest, cup holders, sometimes grouped with seating.

Package Tray A molded or formed panel behind the rear seat, 

sometimes contains accessory brake light.

Carpeting/Flooring Acoustical sound absorption; padding and carpet, 

insulation and accessory mats sometimes flooring may be 

sold as part of a combined acoustic package, also 

involving other sound abatement components, such as 

wheel well liners and under hood insulation

Door 

Modules

19 Convenience 

Items

A door panel system containing door insulation, door trim 

assemblies/panels, map pocket trim, cup holders, ash 

trays, seatbelt retractor covers, speaker grills, armrests, 

switch panels and handles

Seatbelt & 

Restraints

16 Seats The seating system contains seat tracks, seat frames, 

foam, trim, map pockets, restraint anchors, head restraint, 
19

ASCM UPG ASCM Description

Group Name

and armrests.

81 Safety Equipment Seat belts, tensioners, clips, air bags and sensors 

assemblies

HVAC 80A, B Air Conditioning 

System

Condenser, heater, ducting, and controls, compressor 

and A/C hardware.

80H, J Heating System

80K, M, C Other Climate 

Control

Electrical Interior 

Electrical

12F-13, 79 Electrical 

Components

Wiring and controls for interior lighting, instrumentation, 

and power accessories, entertainment system.

85 Accessories 

Equipment

Chassis 

Electrical

36K Chassis Electrical ABS electrical system (wiring, sensors, processors), 

traction control

Exterior 

Electrical

14,20 Molding and 

Ornaments

Head lamps, fog lamps, turn signals, side markers, tail 

light assemblies

Final 

Assembly

Interior

Chassis

Powertrain

Electronics

Other 

Systems

Final assembly of vehicle components is represented at 

the level of five major vehicle subsystems under which 

components are grouped