Value

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Introduction

A smooth, continuous asphalt surface adds to pavement longevity1 and requires less maintenance than rougher roads.2 Reports show that 44 percent of the nation's major roads are in poor or mediocre condition, costing motorists $130 billion a year in vehicle repairs and operating costs. Furthermore, 45 percent of our major urban interstates experience congestion during peak hours, which costs drivers $170 billion per year in wasted time and fuel costs.3 That not only hurts the national economy, it also deals a hefty blow to strained household budgets.

Thinlays

With asphalt pavements, efficiency can be quickly restored through simple maintenance or preservation methods such as Thinlays, which extend the life of an asphalt pavement and is an effective use of materials and money. Traffic congestion can be minimized by increasing travel lanes with quick-to-construct asphalt pavements. Staged construction allows for roads to be built to handle today’s traffic volumes and then upgraded over time to meet changing traffic patterns and loads.

 

Perpetual Pavements

Asphalt’s value is also demonstrated in its low life-cycle costs. It’s recently been shown that new asphalt pavements last 18 years on average without maintenance.4  In addition, the design and construction  Perpetual Asphalt Pavement account for the structural needs of the roadway in the future, allowing for routine maintenance to create a like-new pavement that never needs to be replaced.5 By contrast, when a concrete pavement reaches the end of its useful life, it must undergo expensive, time-consuming replacement from the base up.

Case Study

Asphalt Highways Are Less Expensive

A 1994 hallmark study of asphalt and concrete interstate pavements proved asphalt’s superior value.

Edited by Chuck MacDonald

Americans like getting their money’s worth, whether it’s with the houses they buy, the phones they use, or the cars they drive. It’s also true about the roads they drive on. A comprehensive studyrevealed that asphalt roads were more economical than concrete in Ohio, Kansas, and Iowa. The life cycle cost analysis (LCCA) in this study was based on actual costs of existing pavements over a given time using historical data from the road-building agency. In all cases, comparisons were made to the greatest extent possible of asphalt and concrete pavements carrying similar traffic and comparable age.

Comparing Nearby Pavements

The three studies were diverse in their approach to the question of which pavement type is more economical. 

  • The Ohio study included five locations on four interstate highways (I-71, I-75, I-475, and I-275) where asphalt and concrete pavements were constructed in close proximity and at approximately the same time. The costs were calculated per square yard of mainline pavement. Researchers used the present worth method of costs, wherein the costs during the analysis period of each project were discounted to the year of the original construction. 
  • The Kansas study examined approximately 218 miles of concrete pavement and 262 miles of asphalt pavement on rural interstate highways across the state. Comparative costs were calculated using the "four-lane mile of mainline pavement" as the unit of measure. 
  • The Iowa study examined three locations on one interstate route where asphalt and concrete pavements were constructed adjacent to each other at nearly the same time. The comparison of costs was made using the "two-lane mile" as the unit of measure. 

The Results

The Ohio results showed that in all cases the initial construction costs of asphalt pavements were about 10 to 25 percent less than the concrete pavements on the same route. The cost savings for the present worth values (or total discounted costs) of asphalt compared to concrete pavements were even more dramatic, ranging from 13 to 107 percent, with most of the savings in the 25 to 70 percent range. 

In the Kansas study, the compared pavements were not the same age, therefore equitable comparisons could not be made using the net present value (or worth) method. The comparisons were made using inflation adjusted dollars. An annual inflation rate of 3.5 percent was used, and all costs were carried forward to 2001 and referred to as "2001 dollars." A total of 218 miles of concrete pavement and 262 miles of asphalt pavement on three interstate highways were evaluated. The asphalt pavement on I-70 extends about 250 miles from the western border of the state to I-135 in central Kansas. The concrete pavement is in three locations: 95 miles on I-70 east of I-135; 68 miles on I-135 south of I-70; and 55 miles on I-35 in the eastern part of the state. 

The nine sections of asphalt on I-70, one each in nine counties and 249.7 miles in length, had an average life-cycle cost of $1.89 million per four-lane mile in 2001 dollars. The five sections of concrete on I-70, one in each of five counties and 95.1 miles in length, had an average life-cycle cost of $3.22 million per four-lane mile in 2001 dollars. See Figure 4 below6


The Iowa study determined total life-cycle costs by calculating the present worth of costs of selected pavements discounted back to 1957 dollars using a discount rate of four percent. Three sections each of concrete and asphalt pavement on I-80 in three counties between Des Moines and Iowa City were analyzed in the study. 

In Iowa County, the 4.58-mile concrete section had present worth costs of $272,000 per two-lane mile. The adjacent asphalt section, three miles long, had present worth costs of $157,528. The 4.64-mile section of concrete pavement in Jasper County showed total costs discounted to 1957 dollars of $290,151 per two-lane mile, while the adjacent 6.43 mile section of asphalt pavement had total costs of $179,136 per two-lane mile. 
The costs are shown in Table 4 below6.

Conclusions

The results of the studies show that asphalt pavement was overall more economical in both initial construction cost and life-cycle costs than comparable concrete pavement. In Ohio, all five of the areas compared showed lower initial construction costs and life-cycle costs for asphalt pavement. 

In Kansas, the 10 asphalt and 11 concrete pavement sections evaluated on three interstate routes showed that asphalt was substantially more economical over the life of the pavement. Initial construction costs of nine asphalt pavement sections in Kansas averaged less than those of five concrete pavement sections on I-70, but one asphalt pavement section on I-35 had a higher initial construction cost than the average of three concrete pavement sections on the same route. See Figure 5 below6:

In Iowa, two asphalt pavement sections were substantially more economical over the life of the pavements than the comparable concrete sections, and one concrete section was slightly more economical in life cycle costs than the comparable asphalt section.

  1. Pavement Lessons from the 50-Year-Old Interstate Highway System: California, Oregon, and Washington. Transportation Research Board. 2007.

  2.  Pavement Smoothness Index Relationships, Final Report. Federal Highway Administration. 2002.

  3. TRIP. Key Facts About America's Surface Transportation System and Federal Funding. September 2018. 

  4. Robbins, M.M., & N.H. Tran (2018). Review of Initial Service Life Determination in Life Cycle Cost analysis (LCCA) Procedures and in Practice (NCAT Report 18-02). National Center for Asphalt Technology, Auburn, Alabama.

  5. Pavement Interactive. "Perpetual Pavements", August 2007.

  6. APA. Pavement Life-Cycle Cost Studies Using Actual Cost Data: A Synthesis. February 2005.