From Tech Transfer Newsletter, Summer 2006 » printer-friendly

Getting In, Getting Out, and Staying Out

Accelerating Urban Highway Rehabilitation with Construction Analysis Software

Getting in, getting out, and staying out when performing road improvements just got easier. As transportation agencies 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. This software, CA4PRS (Construction Analysis for Pavement Rehabilitation Strategies), can also help regional, county, and city planners and engineers select economical rehabilitation strategies while minimizing disruption to drivers and the surrounding community.

CA4PRS can be used to identify optimal rehabilitation strategies that balance convenience and efficiency of construction for the agency, inconveniences created for 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.

Success Stories

Since 1999, Caltrans has used CA4PRS on high traffic volume rehabilitation projects in urban areas. In two recent scenarios, CA4PRS was used to develop a staging-construction plan for the I-710 project in Long Beach in 2003, an area with an average daily traffic (ADT) of approximately 160,000. Using the software, Caltrans reconstructed 26 lane-miles of long-life asphalt concrete over the span of eight 55-hour weekend closures. CA4PRS analysis warned that the contractor's initial construction staging-plan submitted to Caltrans, most likely triggered by the incentive/disincentive clause that compensated the contractor $100,000 per weekend closure, was overly optimistic. The contractor revised his production plan based on the production levels estimated by CA4PRS. Actual production performance monitored during construction was within 5 percent of those estimates.

As part of an overall "rapid rehab" strategy, CA4PRS was also used by Caltrans to plan for the reconstruction of a 2.8-mile stretch of concrete pavement on I-15 in Devore in 2004. The ADT for weekday commuter traffic is 140,000, and on weekends when Los Angeles-area residents use the corridor to travel to and from Las Vegas, the ADT is 120,000. CA4PRS helped Caltrans balance the competing concerns of construction schedule, traffic impacts, and agency costs. CA4PRS was used to analyze four closure scenarios: 72 hours on weekdays, 55 hours on a weekend, 10 hours at nighttime, and a 24/7 continuous closure of one roadbed. The software indicated that continuous closure would be the most economical and least disruptive scenario, resulting in a 25-percent cost reduction for construction and traffic control or $6 million in savings when compared with the more commonly used 10-hour nighttime closure schedule practice.

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, Chief of 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.

CA4PRS has also been used by the Minnesota Department of Transportation to develop the construction schedule for resurfacing projects on I-494 and I-393 and by the Washington State Department of Transportation 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, one of the highest traffic volume locations in Washington State.

About the Software

CA4PRS was developed by researchers at the Institute of Transportation Studies at the University of California Berkeley under a Federal Highway Administration (FHWA) pooled-fund study in cooperation with state Departments of Transportation in California, Minnesota, Texas, Florida, and Washington State. 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 user-friendly software is powerful and flexible, with a conventional look and feel. It has a multiple-document interface that allows numerous projects and analyses to be viewed and compared simultaneously.

How to Get the Software

CA4PRS was developed and is owned by the University of California. However, Caltrans holds an unlimited free license, so that Caltrans planners and engineers can download the software at any time. State DOTs in Minnesota, Texas, Florida, and Washington State hold unlimited free licenses as well.

For local agencies and state DOTs in states that did not participate in the original pooled-fund consortium, the software is available for a licensing fee: $1,000 for government agencies; $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
  University of California Berkeley
  Institute of Transportation Studies:
  510-665-3637
  eblee@berkeley.edu
• Michael Samadian
  Caltrans
  Division of Research and Innovation
  916-324-2048
  michael_samadian@dot.ca.gov

Information on the software is also available online at www.dot.ca.gov/research/roadway/ca4prs/index.htm.

Reprinted with permission from the Federal Highway Administration's June 2006 Focus, which is available online at www.tfhrc.gov/focus/june06/index.htm.

© 2008 Regents of the University of California