Use of State-of-the-Practice Tool for Designing Roadways Reduces Costs by $15 Million

By Rebecca Tate, Process Improvement Intern

April 14, 2016

The use of state-of-the-art software has improved a key process at the Colorado Department of Transportation (CDOT) and, in turn, has dramatically improved the quality of our roads, and saved Colorado taxpayers roughly $15 million in material costs. 

All highway pavement is not created equal. Factors such as expected load and geographic location influence the thickness and design of the pavement used on a construction project. Until recently, CDOT's pavement designs were based on findings from road tests conducted in the late 1950s. During this time, the main industry group for state transportation agencies—now known as the American Association of State Highway and Transportation Officials, or AASHTO—built a track in Ottawa, Ill., with varying pavement structures. This track was subjected to moving loads to determine the durability of pavement over time. 

Pavement design guides were then developed that were used across the country. These design guides were updated periodically to include more variables that could impact the effectiveness of the pavement. The most recent update, from 1998, includes 20 inputs that can be modified based on the unique situation of a project to determine the appropriate pavement design.

State-of-the-Practice
Highway

This all changed in 2014 when CDOT pavement designers began using a new software called AASHTOWare Pavement – ME Design. The ME stands for "Mechanistic-Empirical." This means that verifiable observations of the material are collected and analyzed to best determine the pavement needed for a project. This software allows CDOT pavement designers, and consultants working on CDOT projects, to better calibrate pavement design for the unique conditions of the project.

While the old method of designing pavement included 20 unique factors, this new system includes 20,000 inputs that can be modified to help design a more effective, longer-lasting pavement. The enhanced functionality allows our pavement designers to design a pavement that is specific to the conditions of Colorado, including our unique climate and soil conditions.

This software has dramatically improved the quality of our roads and saved Colorado taxpayers roughly $15 million in material costs. According to Jay Goldbaum, CDOT pavement design program manager, "Before this software, we tended to over-design our roads. Now that we have a better understanding of the design, given the unique situation of the project, we can design our roads more efficiently and have a better understanding of the maintenance needs of our roads."

When it comes to pavement design, CDOT is leading the pack. Twenty-eight transportation agencies are licensed to use this AASHTO software across the United States and Canada. Of those 28, CDOT is one of only five transportation agencies that have calibrated and validated the hot-mix asphalt and Portland cement concrete pavement models in the software. This is just one of the ways that CDOT is using technology to ensure the safety of our roads as we continue on our way to becoming the best DOT in the country.