Many State Departments of Transportation (DOT's) often use a subjective evaluation program to assess the condition of their roadway assets. Because pavement markings are typically only a small part of these assessment programs and the subjective nature of visual assessment, the ratings may notalways be accurate in identifying roadways with inadequate markings. This research sought to evaluate the accuracy of visual assessments of pavement markings. The Texas Transportation Institute conducted two separate nighttime evaluations as a part of the Texas Department of Transportation (TxDOT) research project 0-5656. The first evaluation was conducted on openroads, and the second was conducted on a closed experimental course. Subjective rating data were collected on pavement markings by several department of transportation (DOT) evaluators. To analyze the data researchers compared the retroreflectivity measurements with the subjective ratings of the pavement markings. For the first night study the average subjective rating of each marking compared to the measured retroreflectivity resulted in a logarithmic R2 value of 0.818. The second night study resulted in a logarithmic R2 value of 0.821 before training and 0.809 after training. The data were also evaluated by marking color and evaluator experience level. Researchers found that the average subjective ratings show acceptable correlation with retroreflectivity measurements, but ratings can show large variations between individuals. The researchers recommended that subjective assessment be considered a viable option for evaluating pavement markings. The researchers also recommend that for any assessment the evaluator be well trained or multiple evaluators can be utilized, averaging the reported ratings in order to provide reliable results.
Samenvatting