Ideally, studies should also be conducted when the pavement is wet and during rain. The flawed methodology and data analysis of this field study led to conclusions that are not only highly questionable, but potentially dangerous. With the emphasis on restoring and rehabilitating existing facilities, both the driving public and construction crews are facing ever-increasing exposure to work zone activities. Potential for driver error is greatest in such areas of change in the normal environment, and safe negotiation requires clear path guidance. These last two points have a major impact in skewing the research results.
Drivers actually see pavement markings as a function of their contrast with the road surface.
New pavement overlays such as those in the test sites are generally very black, providing excellent contrast to the yellow marking tape. The retroreflective properties of the newly applied marking tape itself provide an extremely bright optical target. Experience and an ample body of evidence indicates improved driver performance in the presence of edgelines. With no indication of lane boundary and limited visual information at the edge of pavement in this study, drivers' focus on the centerline was even more acute. Data Interpretation With a wide expanse of blacktop in a nearly dark environment and a brilliant ribbon of yellow to follow as in this study, drivers should perform relatively consistently.