U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
|Accelerating Infrastructure Innovations|
Publication Number: FHWA-HRT-06-026
Date: June 2006
Getting in, getting out, and staying out just got easier. As transportation departments increasingly turn their focus from new construction to rehabilitating and reconstructing existing highways, accelerating construction is key to reducing problems with congestion, safety, and user delays, particularly in heavily traveled urban areas. As part of its overall traffic management plan, the California Department of Transportation (Caltrans) is using a new software tool aimed at reducing highway construction time and the resulting impact on traffic. CA4PRS (Construction Analysis for Pavement Rehabilitation Strategies) is designed to help planners and engineers select economical rehabilitation strategies while minimizing disruption to drivers and the surrounding community.
CA4PRS was developed by the Institute of Transportation Studies at the University of California at Berkeley under a Federal Highway Administration (FHWA) pooled-fund study. California, Minnesota, Texas, and Washington State participated in the study. The software was recently selected as a priority technology for 2006 by the American Association of State Highway and Transportation Officials' Technology Implementation Group.
|The CA4PRS software can be used to identify optimal rehabilitation strategies that balance the construction schedule with inconvenience to drivers and transportation agency costs.|
CA4PRS can be used to identify optimal rehabilitation strategies that balance the construction schedule with inconvenience to drivers and transportation agency costs. The program considers the "what if" scenarios for such variables as rehabilitation strategy; construction window (i.e., nighttime, weekend, or continuous closures); number of lanes to be closed for rehabilitation; material selection; pavement base type; and the contractor's logistics, including access to the site and production rates. The CA4PRS results can also be integrated with traffic simulation tools to estimate road user delay costs arising from construction. The software aids in establishing schedules, developing staging-construction plans, estimating cost (A) + schedule (B) contracts, and calculating incentive and disincentive specifications for contracts.
"CA4PRS gives you the tools to analyze the best options to minimize costs and delays to the public," says Randell Iwasaki, Chief Deputy Director of Caltrans. Since 1999, Caltrans has used the software on high traffic volume rehabilitation projects in urban areas. On I-10 in Pomona, for example, which has an average daily traffic of 200,000, CA4PRS was used to analyze a 2.8 lane-km (1.8 lane-mi) concrete truck lane replacement that employed fast-setting hydraulic cement concrete. The project was completed in a 55-hour weekend closure of one 4-lane roadbed in 2000. CA4PRS was also used to develop a staging-construction plan for the I-710 project in Long Beach in 2003, where 26 lane-km (16 lane-mi) of asphalt concrete was reconstructed over the span of eight 55-hour weekend closures. This project was completed two weekends ahead of schedule.
As part of an overall "rapid rehab" strategy, Caltrans used CA4PRS to plan for the reconstruction of a 4.5-km (2.8-mi) stretch of concrete pavement on I-15 in Devore in 2004. This eight-lane corridor has a high volume of weekday commuter traffic and an even higher average daily traffic of 120,000 on weekends, when Los Angeles area residents use the corridor to travel to and from Las Vegas. Using CA4PRS as part of its preconstruction analysis, Caltrans sought to integrate the competing concerns of construction schedule, traffic impacts, and agency costs. Four construction roadway closure scenarios were compared: 72 hours on weekdays, 55 hours on a weekend, 10 hours at nighttime, and a 24/7 continuous closure of one roadbed. Caltrans concluded that the continuous closure would be the most economical and least disruptive scenario. Compared to the commonly used 10-hour nighttime closure, the continuous closure would result in a 25-percent reduction in agency costs for construction and traffic control, for a total of $6 million in savings.
|Caltrans used CA4PRS to plan for the reconstruction of a 4.5-km (2.8-mi) section of I-15 in Devore, CA|
|CA4PRS was used to develop a staging-construction plan for the I-710 project in Long Beach, CA. This project was completed in eight 55-hour weekend closures.|
The I-15 project was completed in two continuous closures of each roadbed in one direction for about 9 days per roadbed, using round-the-clock operations. The project would have taken 10 months using traditional nighttime closures. In addition to speeding up the project, "we were able to achieve better quality using continuous closures versus the nighttime closures," says Larry Orcutt, Division Chief for Caltrans' Division of Research and Innovation. Feedback from the public was also very positive, notes Orcutt. The northbound lanes were closed for construction first, with traffic switched to the southbound side using median crossovers at the ends of the work zone. Separated by Quickchange® Moveable Barriers, the two directions of traffic shared the southbound lanes as counter-flow traffic during construction. This process was then repeated for the reconstruction of the southbound lanes.
The Minnesota Department of Transportation has also used CA4PRS for resurfacing projects on I-494 and I-393. The Washington State Department of Transportation, meanwhile, has used it to analyze rapid rehabilitation strategies for two projects on I-5 in Seattle, including the reconstruction of a portion of I-5 that runs underneath the Convention Center, which is one of the highest traffic volume locations in Washington State.
CA4PRS will be upgraded over the next 2 years. "We are going to enhance the software by adding more rehabilitation scenarios," says Michael Samadian, Pavement Research Branch Chief for Caltrans' Division of Research and Innovation. New features to be added will include modules for analyzing continuously reinforced concrete pavement, strategies for highway widening projects, and interchange improvements. The long-term plan also includes adding a pavement performance prediction module, so that the software can be used for life-cycle analysis.
The user-friendly software runs on Microsoft Windows® 95 or higher operating systems. It has a multiple-document interface that allows numerous projects and analyses to be viewed and compared simultaneously.
For State transportation departments that did not participate in the original pooled-fund consortium, the software is available for a licensing fee of $1,000 ($3,000 for industry users and $750 for academia). Two-day training workshops are also available. For more information on licensing the software or holding training workshops, contact E.B. Lee at the University of California at Berkeley's Institute of Transportation Studies, 510-665-3637 (email: firstname.lastname@example.org), or Michael Samadian at Caltrans, 916-324-2048 (email: email@example.com). Information on the software is also available online at www.dot.ca.gov/research/roadway/ca4prs/index.htm.