Analysis of the Clearance Time of Roadblock Events Caused by Geohazards in Bhutan

The importance of providing precise Real Time Information (RTI) to road users has become one of the key roles for the concerned government agencies in Bhutan to ensure the safety of road commuters and also regulate the smooth flow of goods and people in the country. However, to date, the essence of RTI is usually compromised, owing to several unforeseen factors and a lack of sufficient resources at the site. Thus, this research studied and analyzed factors governing the clearance time of roadblock events caused by road geohazard such as landslide, rockfall, flood, etc. Statistical and Geospatial analyses were carried out on the roadblock data (2020) obtained from the Department of Roads. A Theissen Polygon technique in the GIS platform was constructed to obtain the rainfall intensity that was recorded during and after roadblock clearance time. Locations of pre-deployed machinery were also included to investigate the relationship between these two variables and the clearance time. Overall, it took an average of 12.2 h to clear the roadblocks that were recorded, with the longest and shortest times recorded in the Phuentsholing and Trongsa region, i.e., 360.2 h and 0.2 h, respectively. Concurrently, the locations that took the longest were those that did not have machinery on-site. The average time for clearing a block with and without machinery was 10.4 h and 13 h, respectively. Concerning the rainfall data, the clearance time was directly proportional to the accumulated rainfall intensity from the occurrence time to the clearance time. Thus, knowing such relationships and patterns can assist agencies in prioritizing locations and allocating necessary resources, as well as improving the predictability of tentative clearance times to reduce errors in sharing RTI with commuters so that they are not misinformed.