| dc.description.abstract | The networks of Provincial Highway and Expressway in Taiwan are almost completed, and new construction projects became few of a few by year. The Maintenance and Rehabilitation (M&R) of the networks is the most important issue for the Directorate General of Highways (DGH), MOTC, Taiwan. Keeping a specific international roughness Index (IRI) to meet the driver requirement is always a concerned by pavement engineers. The study was based on the above background to build up, and the objective of this study is to improve or keep the IRI of the Total line of Expressway No. 61. The K-mean analysis and regression analysis was adopted to analyze traffic volume, IRI, Capital budget from 2008 to 2019 in this study. Based on K-means, the heavier traffic volume sections were mostly located in the Second Maintenance Office, and only one was mostly located in the First Maintenance Office. The study was tried to discover the relationship between IRI and capital budget. Unfortunately, the relationship between IRI and capital budget in the same years was of no significance. The relationship between IRI and the Capital budget of the last year was better than above. The linear relationship between ΔIRI and the Capital budget of the last year in the Second Maintenance Office was the best model of this study, and the explanation coefficient was above 0.7. In addition, the capital budget of M&R should be larger than a specific amount, and it would be helpful to improve IRI. In other words, if the M&R is only focusing on a 3-5 cm thickness surface layer, it would be insufficient to improve IRI. Based on the above, DGH should make up an annual specific budget to M&R, and the IRI of expressway No. 61 would be improved or kept. | en_US |