Transportation Deployment Casebook/The Life Cycle of the Interstate Highway System

The Interstate Highway System is an interregional network of high-speed roads authorized under Dwight D. Eisenhower on June 29, 1956.[1] The network connected metropolitan areas, landmarks, and industrial areas, as well as provided mobility for the national defense system.[2] The Interstate Highway Network has provided efficient routes for shipping, travel, and defense. It has lead to decreases in travel time and freight costs. With this connectedness, the United States has become a leader in super-highways with over 47,000 miles of road.

S-Curve Modeling the Birth, Growth, and Maturity of the Interstate Highway System

The S-Curve is used to model the life cycle of transportation modes. It depicts the birth, growth, and maturity of the mode.

The Life Cycle of the Interstate Highway System

The S-Curve model depicted below shows the mileage of the Interstate Highway System. It begins at a point greater than zero, because paved interregional roads existed before 1956. With the Federal-Aid Highway Act of 1956, the Interstate designation was implemented. This designation was given to many existing roads. The existing interregional road mileage cannot be extracted from the road data in a meaningful way.

Methodology

The S-Curve model follows the formula S(t) = K/[1+exp(-b(t-t0)] where

• K= point of saturation
• b= a constant
• t= year
• t0= inflection point representing 1/2 K

Using this method, the S-Curve was shown to be a good fit, with an R^2 of 0.91. The R^2 is an indicator of the goodness of fit for the regression used to estimate this curve. K was estimated to be only slightly higher than the existing network, 48,500 miles, due to the slowing growth of roads and a shifted focus to maintenance by the Federal government. T0, the point where mileage was 24,250, was determined to be 1922, following the growth patterns backward. Because the data begins after t0, only the top of the S curve is shown.
Data was collected from the Highway Statistics publication provided by the Federal Highway Administration [3]

Before The Interstate Highway System

World War I Era

Long distance freight in the early 20th century was relegated shipped via railroads.[4] World War I increased demand of American goods in Europe. As railroads reached maximum capacity, merchandisers turned to semi freight to get their goods to port. As heavy loads were brought across America’s roads, they quickly deteriorated. With this deterioration, President Woodrow Wilson signed the Federal-Aid Highway Act of 1916. This increased federal funding for highways, provided money for rural post roads, and dedicated monies for roads through public lands.[5]

The Great Depression and World War II

Economy

From 1950 to 1989, 25% of the nation's productivity increase is attributable to highways (the Interstate System plus all other urban and rural highways).[1] The larger network provided more mobility of people and goods, expanding the market and competition. With the improved road network semi freight became competitive with railroads. Prior to the interstate system, the market for semi freight was primarily local deliveries. Freight costs decreased with the increase in road quality. With the decreased freight costs, semi freight was now competitive with rails. This lead to lower cost freight and increased reliability with deliveries.

Maturation of the Interstate System

The physical and economic landscape of America has permanently changed with the construction of the Interstate Highway System. The federal and state governments have shifted their focus from expansion to maintenance and from road expenditures to mass transit programs. Even further, some local governments, with the support of the federal government have begun to tear down certain elements to "correct" the social maladies that occurred during construction.

Problems with the System

The Highway Trust Fund is no longer funding highways exclusively. After 1973, these funds have been used to support light rail, mass transit, bus and bike lanes, among other alternative transportation modes.[9] This may reflect the increased advocacy for a public transit system that more closely resembles international ones.
In 1998 the Transportation Equity Act for the 21st Century added reconstruction to the authorized activities in the Interstate Maintenance Program. Previously the only federally funded activities were resurfacing, restoration, and rehabilitation.[2] The interstate system solved many problems in the 20th century, but since falling into disrepair, has many problems it now needs solved. Most of the infrastructure has surpassed its life expectancy. In 1997, over five percent of bridges on the Interstate Highway System have been deemed structurally deficient.[10]
Congestion in major urban areas is a serious concern. It has been estimated that Americans spend 4.2 billion hours stuck in traffic, to the toll of \$78.2billion. And it's only getting worse; the average daily vehicle miles traveled during congestion has grown from 25.9% in 1995 to 31.6% in 2004 with some regions exceeding that.[11]
The construction of the Interstate Highway System was highly contested. For many reasons, including environmental and racial and social inequality in the construction process, the highway was rarely popular in the neighborhoods it dissected. Many years later, cities have proposed the destruction of these interstates. The Park East Freeway in Milwaukee, Wisconsin was removed after Mayor John Norquist campaigned heavily for the removal and a return to the street grid.[9] But Milwaukee is not alone in the desire to remove urban highways. New York, Boston, and others have already replaced their highway systems with tunnels or boulevards and cities like Nashville, Cleveland, Philadelphia, and St. Louis have discussed and planned the removal of their urban highways, with the support of the Federal Government.[9]

Reference List

1. Cox, Wendell & Love, Jean. (June 1996). The Best Investment A Nation Ever Made. Retrieved from http://www.publicpurpose.com/freewaypdf.pdf
2. a b c Federal Highway Adminstration. (Updated 2012). Dwight D. Eisenhower National System of Interstate and Defense Highways. Retrieved from http://www.fhwa.dot.gov/programadmin/interstate.cfm on November 4, 2012.
3. Office of Highway Policy Information. (n.d.). Highway Statistics Series. Retrieved from http://www.fhwa.dot.gov/policyinformation/statistics.cfm on November 4, 2012.
4. a b Federal Highway Administration. (n.d.). Moving the Goods: As the Interstate Era Beings. Retrieved from (http://www.fhwa.dot.gov/interstate/freight.htm) on November 4, 2012.
5. a b John Williamson. (2012). Federal Aid to Roads and Highways Since the 18th Century: A Legislative History. Retrieved from http://www.fas.org/sgp/crs/misc/R42140.pdf on November 4, 2012.
6. a b Petrsoki, Henry. (2006). Engineering: On the Road. American Scientist, 94(5), 396-399.
7. Garrison, William L. & Levinson, David M. (2006). The Transportation Experience. New York: Oxford University Express.
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9. a b c Mohl, R. A., & Rose, M. H. (2012). The Post-Interstate Era: Planning, Politics, and Policy since the 1970s. Journal Of Planning History, 11(1), 3-7
10. Committee on Transportation and Infrastructure. (2007). Highway Bridge Conditions in the United States. Retrieved from https://apps.asce.org/reportcard/pdf/NHS%20Bridge%20Reconstruction%20Initiative.pdf on November 4, 2012.
11. American Society of Civil Engineers. (2009). Infrastructure Fact Sheet. Retrieved from http://www.infrastructurereportcard.org/sites/default/files/RC2009_roads.pdf on November 4, 2012.