Software that Speeds Up Pavement Rehabilitation: program developed at PRC poised for national rollout
Replacement of outer lane of I-15 near Devore in 2004: a major freight corridor connecting Los Angeles to the Midwest that also serves many commuters between the high desert and the Los Angeles basin.
A Pavement Research Center (PRC) software program that saves time and money and cuts congestion by devising the optimal way to schedule and design highway rehabilitation projects is poised for a national rollout, with backing from the California Department of Transportation (Caltrans) and four partner state DOTs, the leading association of state highway agencies and the Federal Highway Administration (FHWA).
The software, Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS), was developed by PRC researcher E.B. Lee as Lee's Ph.D. project in the late 90s, with major support from Caltrans and the DOTs of Florida, Minnesota, Texas and Washington.
Caltrans designated CA4PRS as its formal design tool for highway rehabilitation projects three years ago, after using it successfully on three projects. In October 2006, CA4PRS received another strong endorsement from the American Association of State Highway and Transportation Officials (AASHTO)Technology Implementation Group, which promotes leading edge techniques. The Federal Highway Administration (FHWA) joined with AASHTO and is helping fund a nationwide promotion of the software as well as training sessions.
"The use of CA4PRS helped Caltrans reduce construction time and save several million dollars in agency costs while also significantly reducing road user costs," notes the Caltrans Web site.
The program allows engineers to work together to fashion the least disruptive and most efficient schedule for highway repairs. Additionally, it enables project planners to test different scenarios and present them to decision-makers and affected parties.
"This software allows the design engineer, the planning engineer, the traffic engineer and the construction engineer to talk to each other. It provides them with the same communication channel," Lee explained.
It does so by using computer models and simulations to rehearse 
different "what-if" situations
involving all the parameters for
a major highway reconstruction project. These include factors ranging from
the type of rehabilitation proposed (e.g., Portland Cement Concrete (PCC),
Crack-seat and AC Overlay (CSOL) or Full-Depth AC Replacement (FDAC)), to
the preferred time windows for projects. Other considerations include contractors'
access to and ability to use different kinds of materials, lane closure tactics,
the thickness of the new pavement, the type of base to be used, the traffic
control and scheduling met
hods, and the curing time and design of the pavement
mixes. All these elements interact in complex ways that are nearly impossible
to predict and control without the software and computer processing power. Additionally, the program can run different versions of the same
project and produce easy-to-understand, highly graphical representations
of the conditions that each choice would produce. This is useful for policy
makers to share their decision-making with the greater public and other participants.
The software program, which is under license by the UC Regents, is already freely available to Caltrans and the four DOTs. The FHWA is working to sponsor licensing for the remaining 45 states, a process that is expected to be completed soon. In addition, a number of universities have acquired an educational license for the CA4PRS software for teaching purposes. Some contractors have also purchased the commercial license to verify their construction staging plans for highway rehabilitation projects.
Caltrans awarded Lee and his team two 2005 Excellence in Transportation Awards for CA4PRS's deployment on the initial repaving project of I-15 in Devore (pictured above) in 2005.
A new version of the software is being rolled out, Lee said. In additional to the projects in Southern California where it has already been used, a major rehabilitation of freeways in and around Riverside County will be guided by the software.
Outside the state, in addition to the four partner DOTs, Michigan and Missouri are in the process of acquiring rights to the program. With the FHWA commitment, the software should be widely adopted in coming months.
Related Links
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" Accelerating Urban Highway Rehabilitation with Construction Analysis Software," FHWA's FOCUS magazine, June 2006.
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"Accelerated Reconstruction Of I-15 Devore Corridor," FHWA's Public Roads Magazine, Jan/Feb 2007.
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Caltrans District 8 Web site describing CA4PRS implementation in the second stage of the pavement rehabilitation project near the junction of I-15/I-215 in the Cajon Pass near Devore.