U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3127

October 20X6

Materials in Use in U.S. Interstate Highways

Printed on recycled paper

Materials Usage

Natural aggregates (construction sand and gravel and 

crushed stone) make up the largest component of nonfuel 

mineral materials consumed in the United States (fig. 1). Most 

of these materials are used in construction activities, such as in 

buildings and roads. In highways, natural aggregates are incorporated into asphalt and concrete and are used as road base.

Roads and Highways

Comprising 9.6 million square kilometers (3.7 million 

square miles), the United States is the third largest country in the 

world. With a large, complex economy, the United States requires 

a vast system of roads and highways in order to move goods and 

supply services and for other travel purposes. Almost 3 trillion 

vehicle-miles (4.8 trillion vehicle-kilometers) were traveled in 

the United States in 2004 (Bureau of Transportation Statistics, 

2005). There is almost 4 million miles (6.5 million kilometers) 

of roads in the United States, with just over 45,000 miles [73,000 

kilometers (km)] composing the Interstate Highway System (fig. 

2) (Federal Highway Administration, 2004). The total distance 

of U.S. roads combined could circle the Earth at the equator 160 

times; the interstate highways, almost two times.

The Interstate Highway System, formally known as the 

Dwight D. Eisenhower National System of Interstate and Defense 

Highways, began to be constructed in the 1950s. Interstate highways were required to meet specific standards to ensure a long 

service life and provide safe travel. Standards included limited 

access, a design to accommodate vehicle speeds of 50 to 70 miles 

per hour (80 to 113 km per hour), a minimum of two travel lanes 

in each direction, 12-foot [3.7-meter (m)] lane widths, 10-foot (3-

m) paved right shoulder, and a 4-foot (1.2-m) paved left shoulder 

(Federal Highway Administration, 2006). A generalized cross 

section of an interstate highway is shown in figure 3.

Materials in Use

The materials used to construct interstate highways are in 

continuous use except for those replaced during maintenance 

and lost through wear and tear. Even during maintenance much 

of the concrete and asphalt that is removed is eventually placed 

back in the highway. A U.S. Geological Survey study showed 

that, in the Denver, Colo., area in 1996, 80 percent of asphalt 

pavement debris and 50 percent of cement concrete debris were 

reused in some capacity, thereby reducing the need for new 

material from mining opeartions (Wilburn and Goonan, 1998).

Figure 4 shows the total quantity as of 2006 of selected 

mineral materials estimated to be in use in the roadways composing the Interstate Highway System. The data that were used to 

Figure 2.  Map showing the National Highway System. Interstate

highways are drawn in blue. Map from Federal Highway

Administration (2006b).

Figure 3.  Cross section showing of a typical interstate highway

with concrete pavement. Data from Bob Bisgard, Asphalt Paving

Company, Golden, Colo., oral commun., 2005.

Concrete

11 inches

Natural

aggregates

21 inches

Compacted

soil

Figure 1.  Graph showing U.S. apparent consumption of raw

materials.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

APPARENT CONSUMPTION, IN MILLION METRIC TONS

YEAR

Natural aggregates

Industrial minerals

Recycled metals

Primary metals
develop figure 4 were extrapolated from published information 

giving the average quantities of material inputs per million dollars 

of construction for major highway construction (Federal Highway Administration, 2003). Estimates are based on a generalized 

model of the Interstate Highway System in which all roadways 

of the system have uniform characteristics. The materials used in 

this analysis were natural aggregates (used in asphalt, concrete, 

and as road base), asphalt (used as a binder with aggregates to 

produce asphalt pavement, or “blacktop”), cement (used as a 

binder with aggregates and water to produce concrete; excludes 

cement in concrete pipe), and steel (used as culvert pipe, reinforcements, and structural support). Bridge railing, clay pipe and 

tile, concrete pipe, corrugated aluminum culvert, guardrail, and 

lumber were not included in the analysis.

This analysis is based on a 42,500-mile (73,000-km) Interstate 

Highway System with four 12-foot (3.7-m) wide lanes. Sixty percent of the system is paved with concrete that is 11 inches (28 centimeters) thick. By volume, concrete is typically 60 to 75 percent 

aggregate, 15 to 20 percent water, 10 to 15 percent cement, and 5 to 

8 percent entrained air (Portland Cement Association, 2006). The 

weight-percent of cement in concrete is similar. For this analysis 

concrete was assumed to be 12.5 weight-percent cement.

The analysis shows that a total of approximately 1.5 billion 

metric tons (Gt) of aggregates, 35 million metric tons (Mt) of 

asphalt, 48 Mt of cement, and 6 Mt of steel is in place in interstate highways. These estimates illustrate the large quantities of 

these materials used in the Interstate Highway System.

The 1.5 Gt of aggregates estimated to be in interstate highways 

is more than 50 percent of the combined estimated sand and gravel 

and crushed stone used in construction in the United States in 2005. 

The 35 Mt of asphalt used in 2005 is slightly more than the total estimated asphalt and road oil used in the United States in 2000 (Kelly, 

2005). The 48 Mt of cement is equivalent to almost 40 percent of the 

cement used in the United States during 2005 (van Oss, 2006).

Summary

The vast system of roads and highways in United States 

provides a critical service to the country’s economy and people. 

The construction of these roads and highways has required and 

continues to require large quantities of materials, such as aggregates, asphalt, cement, and steel. The materials are providing 

services every time the road or highway is used.

References Cited

Bureau of Transportation Statistics, 2005, National transportation statistics 2005, Table 1-32—U.S. vehicle-miles: Bureau 

of Transportation Statistics Web site at http://www.bts.gov/

publications/national_transportation_statistics/html/

table_01_32.html. (Accessed May 26, 2006.)

Federal Highway Administration, 2003, Highway statistics, 

2003, Usage factors for major highway construction materials 

and labor: Federal Highway Administration Web site at 

http://www.fhwa.dot.gov/policy/ohim/hs03/htm/pt4.htm. 

(Accessed January 21, 2006.)

Federal Highway Administration, 2004, Highway statistics, 

2004, Section V—Roadway extent, characteristics and performance, Table HM-15: Federal Highway Administration 

Web site at http://www.fhwa.dot.gov/policy/ohim/hs04/htm/

hm15.htm. (Accessed January 21, 2006.)

Federal Highway Administration, 2006a, Dwight D. Eisenhower 

National System of Interstate and Defense Highways: Federal 

Highway Administration Web site at http://www.fhwa.dot.gov/

programadmin/interstate.html. (Accessed January 13, 2006.)

Federal Highway Administration, 2006b, National highway 

system (NHS): Federal Highway Administration Web site 

at http://www.fhwa.dot.gov/hep10/images/nhsjpg.jpg. 

(Accessed April 19, 2006.)

Kelly, T.D., 2005, Organics (nonrenewable), in Kelly, T.D., and 

Matos, G.R., comps., Historical statistics for mineral and 

material commodities in the United States (ver. 1.0): U.S. 

Geological Survey Data Series 140, available only online at 

http://minerals.usgs.gov/minerals/ds/2005/140/organics.pdf. 

(Accessed January 31, 2006.)

Portland Cement Association, 2006, Concrete basics, Portland 

Cement Association Web site at http://www.cement.org/

basics/concretebasics_concretebasics.asp. (Accessed February 9, 2006.)

van Oss, H.G., 2006, Cement: U.S. Geological Survey Mineral 

Commodity Summaries 2006, p. 44-45. (Also available online 

at http://minerals.er.usgs.gov/minerals/pubs/commodity/

cement/cemenmcs06.pdf.)

Wilburn, D.R., and Goonan, T.G., 1998, Aggregates from natural 

and recycled sources—Economic assessments for construction applications—A materials flow analysis: U.S. Geological 

Survey Circular 1176, available only online at http://pubs.usgs.

gov/circ/1998/c1176/c1176.pdf. (Accessed April 24, 2006.)

For more information, contact:

Daniel E. Sullivan

U.S. Geological Survey

Box 25046

Denver Federal Center, Mail Stop 750

Denver, CO 80225–0046

Telephone: (303) 236–8747 x267

E-mail: desulliv@usgs.gov

Figure 4.  Pie chart showing selected materials estimated to be in

use in the National Highway System. Data are in million metric tons.

Natural

aggregates, 

1,500

Cement,

48

Asphalt,

35

Steel, 6