Tag Archives: NCHRP

New Project: Guide for Converting Severely Distressed Paved Roads to Unpaved Roads

Local agencies are increasingly looking at converting low-trafficked paved roads to gravel at the end of their life span to make budgets stretch. However, agencies have few resources to guide them in this process.

The Minnesota Local Road Research Board recently approved funding for a guidebook on effective practices for converting severely distressed paved roads to unpaved roads. The document will help engineers select roads for conversion, safely conduct conversions and communicate the rationale to the public. No such published document currently exists.

Montana State University researchers has been hired to develop the guidebook based on needs the research team previously identified in the National Cooperative Highway Research Program’s Synthesis 485, “Converting Paved Roads to Unpaved. The guidebook, anticipated to be published in late 2019, will include flowcharts that guide practitioners through decision-making processes. A companion webinar is also planned.

The guidebook will be divided into chapters, which will cover:

  • Methods to determine if a road is a candidate for conversion and determine the existing road materials and condition.
  • Methods to convert a road from paved to unpaved.
  • Methods to assess the life-cycles cost of construction and maintenance of the unpaved road.
  • Tools to effectively inform and communicate with the public
  • Safety implications of converting a severely distressed paved road to an unpaved road.

Background
While low- volume roads are typically identified as having an annual average daily traffic (AADT) of less than 400, roads that are appropriate candidates for conversion will typically have an AADT of less than 150.

These roads are often used by agricultural and extraction industries or to access homes and recreational areas. The type of road users, traffic patterns and vehicle types are all factors that need to be considered in the decision to unpave a road. Other factors include road condition, safety, agency maintenance and maintenance capabilities, as well as a life-cycle cost comparison of maintenance options (continued maintenance of the deteriorating road, rehabilitation of the paved road or conversion to an unpaved surface).

According to the research team, very limited information is available about converted roads, and what information is available often comes in the form of newspaper articles and anecdotal accounts of road conversions.

The document will serve as a formal and peer-reviewed information source. The use of the guide and acceptance of the practice of converting from paved to unpaved surfaces (unpaving) where warranted will provide a case for the acceptance of road conversions as another low-volume road management strategy.

Watch for new developments on this project.  Other Minnesota research can be found at lrrb.org and MnDOT.gov/research

 

MnDOT leaders highlight TRB benefits at forum

As a graduate student 35 years ago, Bill Gardner attended his first Transportation Research Board Annual Meeting, and he still remembers the thrill.

“I felt like a kid in a candy shop,” recalled Gardner, who heads MnDOT’s Office of Freight and Commercial Vehicle Operations. “I was amazed at the diversity of topics… You could find people who have devoted their whole lives to the hazards of rural mailboxes.”

Gardner and other MnDOT leaders on Tuesday recounted their experiences from this year’s annual meeting — which drew more than 10,000 participants — and encouraged other MnDOT staff to get involved in the organization, which helps set national transportation guidelines, oversees collaborative research and facilitates the exchange of information.

“We’re heavily involved, but I think we could be more involved,” said Modal Planning and Program Management Director Tim Henkel, who has been part of the TRB for more than 20 years.

Henkel said TRB involvement benefits MnDOT in several ways, including access to national and international experts, the ability to keep tabs on hot-button issues and having a seat at the table in decision-making.

“It makes us a more enlightened and informed decision-making body,” Henkel said.

MnDOT has more than 60 staff serving on 114 TRB committees and contributes $125,000 annually to the TRB core program, gaining $127 in collaborative research for every $1 it contributes.

“It’s a very intense and very busy experience," said Chief MnDOT Engineer Deputy Commissioner and Chief Engineer Sue Mulvihill, who displayed the thick program book and other materials from this year’s Transportation Research Board Annual Meeting.
“It’s a very intense and very busy experience,” said MnDOT Deputy Commissioner and Chief Engineer Sue Mulvihill, who displayed the thick program book and other materials from this year’s Transportation Research Board Annual Meeting.

As part of a series of staff forums they will hold throughout the year, MnDOT leaders chose to highlight the TRB, which met in January. (MnDOT employees interested in attending next year or getting involved in the TRB should speak with their supervisor.)

State Bridge Engineer Nancy Daubenberger, who serves on a TRB subcommittee and gave a presentation at the recent conference, said it helps to hear about the challenges faced by agencies around the country.

Assistant Engineering Services Division Director Amr Jabr, who attended for the first time, said he used a smartphone app just to decide which of the approximately 3,500 sessions he wanted to attend.

“I thought it was an extremely good experience,” he said. “I picked up a lot of information and made a lot of new contacts.”