Carbon Emissions Facts and Figures

Shorter material haul trips means…

CalTrans has prepared several estimates that demonstrate the benefits of using local material supplies. Based on CalTrans' work, if material haul trips can be reduced on average by 15 miles, then:

  • Material haul miles would be reduced by 282 million miles per year.
  • Diesel fuel consumption would be reduced by 44 million gallons.
  • The diesel fuel saved not only reduces air pollutants, but also removes over 400,000 metric tons of greenhouse gases.

Transporting from shorter distances saves money.
Most aggregates are transported by truck. The cost of trucking aggregates increases 15 cents per ton for every mile hauled. Given that even one mile of a six lane highway requires over 110,000 tons of aggregates, each mile of transport would add one-half million dollars to the base cost of the aggregates for such a project.

Transporting from shorter distances protects the environment and reduces traffic.
CalTrans estimates a current average hauling distance of 50 miles. If the trip length can be reduced by even 15 miles, then diesel fuel consumption can be reduced by 44 million gallons annually, and truck emissions by 835 tons per year. Traffic congestion would be reduced. And an estimated $705 million per year would be saved on material transportation costs.


The 335 metric tons of CO2 equivalent emissions produced from the average CalTrans road construction project that requires delivering construction materials 50 miles is equivalent to driving a Hummer H-1 more than nine times around the equator.

(Sources: Based upon assumed 10 miles per gallon for a Hummer H-1 and using the California Climate Action Registry CO2 emissions formula for diesel fuel.)

In 2005, California imported enough cement, mostly from Asia, to produce enough concrete to construct five Hoover Dams.

(Source for total concrete used to construct the Hoover Dam, completed in 1936: "Wonders of the world Databank," Public Broadcasting Service,

Cement imported to California from Asia—which accounts for 40 percent of the total cement used in this state—creates an estimated 25 percent more CO2 emissions, or greenhouse gases, than cement produced in California.

(Source: April 10, 2008 state Air Resources board workshop on implementation of AB 32, California's 2006 law seeking to curb greenhouse gases, "AB 32: the California Global Warming Solutions Act of 2006 Overview: AB 32 Implementation Status,"

The 1.3 million metric tons of CO2 from importing foreign cement accounts for about 10 percent of greenhouse emissions from all the international commercial jet travel in and out of California based on 2004 reporting, the most recent year for which data is available.

(Source: Based on California Air Resources Board-adopted greenhouse gas emissions inventory for the state from 1990 through 2004.)

Decreasing the distance aggregate is shipped by an average of 15 miles across the state, saving 44 million gallons of diesel fuel, would also reduce tail pipe emissions by 835.4 tons a year of pollutants regulated by the state Air Resources Board that are linked to incidents of cancer, asthma and other serious health problems.

(Sources: CalTrans analysis, based on the California Air Resources Board emission factors estimates and assuming an average 55 to 60 miles per hour speed and a reduction of 282 million miles of truck travel.)

In 2005, California imported enough cement to make nearly 24 million cubic yards of concrete. That's enough concrete to build a sidewalk four feet wide and three inches deep five times around the earth at the equator.

(Source: Calculated based on data from "Wonders of the world Databank," Public Broadcasting Service,

In 2005, California imported enough cement to build a sidewalk four feet wide and three inches deep halfway to the moon.

(Source: Based on the calculation of the estimated distance to the moon of 233,784 miles surface to surface.)

In 2005, California imported enough cement to produce concrete that would fill the Louisiana Superdome five times over.

(Source: U.S. Army Corps of Engineers April 4, 2006 "Weekly Brief" estimate of Superdome volume at 4.6 million cubic yards.)

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