The researcher is somewhat concerned about the results of the study described in Example 14.2, because he was certain that at least one of the paints would show some improvement over the currently used paint. He examines the road conditions and amount of traffic flow on the 16 sections used in the study and finds that the roadways had a very low traffic volume during the study period. He decides to redesign the study to improve the generalization of the results, and will include four different locations having different amounts of traffic volumes in the new study. Chapter 15 will describe how to conduct this experiment, in which we may have a second source of variability, location of the sections.