Highway Departments Move Ahead with Performance Standards

Alexander Volokh
Privatization Watch, June 1996

Since the mid-19th century, state departments of transportation have followed a "materials and method specification" approach to highway construction. As states try to keep up with changing technology and improve the quality of their highways at minimum cost, more states are considering adopting performance- related standards for highway construction.

Traditionally, the highway agency specifies the exact materials and procedures for the contractor to follow. This approach, which ignores variability in material properties, construction techniques, and the contractor's skill and integrity, has its pitfalls. Most importantly, it impedes innovation. After World War II, contractors became more knowledgeable about roadway technology and frequently initiated innovations in construction methods. As method specifications were codified in written documents and often supported by deeply- ingrained attitudes, they often lagged behind and sometimes even delayed advances in construction technology.

As Darrell Harp, assistant commissioner of the New York DOT, puts it: "What is the most devastating aspect of [materials and methods specifications]? The contractor can't use his own initiative because he has little option when he is told precisely what he must do, what type of materials he must incorporate and exactly how it is to be put in place. Innovation is stymied. Another drawback is that the improvement of the product will be very slight and it is doubtful that you will see a reduction in overall cost. If we were to live forever with materials and methods specifications, I suppose we would still be driving around in Model 'Ts.'"

According to the National Cooperative Highway Research Program, true "performance-related standards":

• are based on properties of the finished product, not on the processes used to produce it;
• consider the variability inherent in the finished product and in the testing processes;
• are based on attributes that have been related to the actual performance of the product through validated quantitative models;
• incorporate sampling and testing procedures whose combined costs are consistent with the importance of the quality benefit being sought; and
• make the contractor's payment dependent on how close the product comes to the level of acceptable quality.

State highway departments are moving toward performance-related standards, but only New Jersey uses performance-related specifications, and only for portland cement concrete and portland cement concrete pavement. According to the NCHRP, "while the research community involved in the development of [performance- related specifications] is well versed in both its theory and practice, awareness within the highway construction community at large seems quite low. . . . [Performance-related specification] development to date has been advanced almost exclusively by a small number of university and industry consultants."

While highway agencies have been making progress, they still often don't rely on measures of performance. Some analysts note that specifying materials or methods may have been the best proxy for performance one could find in the past; when performance is difficult to measure, "doing it the way we've always done it" may have had some justification. Now, though, these analysts say governments should move toward performance standards and away from specifying materials.