New Guidelines Announced for Evaluating Unpaved Road Design Research

A first of its kind report to help engineers interpret research studies for better design decisions


A first of its kind report will help educate the construction and engineering community on how best to conduct and evaluate field test research in subgrade stabilization and how to apply this vital information to make the best unpaved-road design decisions.

Tensar, a supplier of geogrid products for construction and roadway applications, has invested in extensive third party research and testing with major test institutes in the North America and Europe throughout the evolution of geogrid technology. Tensar is now offering the report, titled “Evaluating Road Design Research,” at no cost from its website. 

This report features a collection of thought leading articles as well as a newly published review of recent field research. It provides a list of 10 questions to ask to ensure the reliability of data derived from unpaved road design studies. 

The research review is from industry experts, Timothy Stark and Robert Swan (Stark Consultants, Inc.), whose report, “Evaluation of Geosynthetic Subgrade Stabilization Field Tests,” reviews the unpaved road study conducted by the Western Transportation Institute (WTI) in 2014, which is referred to as the Montana Study. 

The Montana Study provides a prime example of the challenges that exist in deciphering results from full-scale comparative field experiments. Stark and Swan point out numerous flaws in the planning and implementation of this study that serve as cautionary lessons for future researchers and the consumers of such research. 

They note that the significant variance in the results of the Montana Study to those of other unpaved road studies and nationally recognized unpaved road design procedures that have gone through significant peer review, calibration and validation, should be of concern.

Tensar recognizes that today’s vast proliferation of information makes it increasingly difficult to distinguish between research that is valid, reliable and unbiased from that which is not,” says Mike Lawrence, CEO of Tensar. “It is the hope of Tensar that this report will provide guidance to those who undertake unpaved road design and geosynthetics research as well as to those who rely on such research for critical engineering and construction decisions,” he added.

Download “Evaluating Unpaved Road Research” at no cost from Tensar’s website.