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A relatively common question people have is "How much do highways costs?"
This question does not have an easy answer. Each highway has unique characteristics such as the terrain it must cross (generally classified as level, rolling, or mountainous), the natural and manmade features on the terrain, type of soil, and other features. In addition, there may be some cost reduction conditions. For example portions of the right-of-way (ROW) might be donated or material excavated from one section of the construction project may be suitable for use as fill in another section of the project. On the other hand, there are sometimes conditions that result in increases in cost such as a requirement for hazardous material remediation, a complex interchange or a long tunnel or bridge. In addition the project may take many years to complete and thus the cost would be subject to considerable inflation. All this makes it essentially impossible to have a standard "highway cost". It also means that any cost estimates done without a detailed study are subject to rather large error bands.
However, to get an idea of the cost of constructing new highways in the 14th amendment highway corridor and the 3rd infantry division highway corridor, it is useful to look at the costs of some recently constructed rural freeways.
In all the cases below, the cost is in nominal rather than constant dollars. The preliminary engineering (PE) and other design activities generally include all cost of environmental impact study and documentation while the construction includes most of the cost of avoiding environmental and cultural resources, minimizing the impacti when unavoidable and mitigating the impact after minimization (the ROW also includes some of these costs). The planning related costs (e.g., related to the State long range plan or the State Transportation Improvement Program) are not included in the costs below but are small relative to the construction, PE or ROW costs.
One such freeway in North Carolinaii that was designated by Congress as a future interstate in 1995 is I-73/74. As noted previously on this site, about 25 miles of I-73/74 were opened to traffic and carrying an interstate sign as of September 2005. About 12 miles of this is signed as I-74, all in Surry County and extends from I-77 to U.S. 52. About 12 and a half miles of this is signed as both I-73 and I-74 and extends from U.S. 220 Alternate south of Steeds in Montgomery County to U.S. 220 Business south of Ulah in Randolph County.
The cost of both sections of I-73/74 freeway sums to about $129 million of which about $9 million was for preliminary engineering (PE) and about $9 million was for ROW (these are in nominal, not constant dollars). The entire portion of this freeway is on new alignment and in rolling terrain (as opposed to flat or mountainous terrain). Some of the cost was incurred prior to the 1995 designation.
Another such freeway in North Carolinaiii is the approximately 14-mile section of I-26 that was completed in 2004. This section, from about one mile south of the Madison and Buncombe County (NC) line to the Tennessee state line, cost about $298 million. Of this amount, about $14 million was for PE and about $19 million for ROW. This section of I-26 was entirely on new alignment. The high cost of this section relative to I-73/74 is mostly because this section is mountainous.
A freeway in Pennsylvaniaiv that was also designated by Congress as a future interstate in 1995 is I-99. As noted previously on this site about 53 miles of I-99 were opened to traffic and carrying an interstate sign as of September 2005. This section, from the Bedford, PA interchange to Tyrone, PA cost about $323 million. Of this, about $19 million was for route studies, PE and final design. The remainder was for ROW (about $36 million) utilities (about $8 million) and construction (about $260 million). About 16 miles of this section is mountainous and the remainder is rolling. All 53 miles are on new alignment.
There are substantial difficulties in estimating the environmental cost associated with highway projects. One reason is that it is not always clear what is and what is not an environmental cost. For example, suppose a noise wall is constructed on top of a retaining wall. Suppose the combination structure is one line item of a contract. Suppose also that placement of material near the retaining wall and the stabilization of the material is part of the overall line item for material acquisition, handling and disposal in the contract. Extracting the portion of the contract that is for the noise barrier (which is clearly an environmental cost as opposed to the retaining wall which may or may not be such a cost) may be a difficult and time consuming matter. More on this subject is available at the FHWA NEPA web site.
i In some cases avoiding an environmental resource or minimizing an impact reduces the construction or ROW cost but increases the cost to highway users or decreases the safety of users somewhat. An example would be where the width of the median and the width of the clear zone next to the traveled way are minimized to reduce impact to a critical habitat.
ii The North Carolina DOT, via email, kindly provided this information.
iii The North Carolina DOT, via email, kindly provided this information.
iv The Pennsylvania DOT, via email, kindly provided this information.
To provide Feedback, Suggestions or Comments for this page contact Stefan Natzke at stefan.natzke@dot.gov or 202-366-5010.
