The Ministry of Transportation and Communications just completed its investigation into the highway landslide that took four lives last year, attributing the accident to natural causes rather than human errors. But the conclusion was soon challenged by the Control Yuan, which held various government agencies responsible for the tragedy.

Following a massive mudslide of Freeway No. 3 that buried four people last April, the Ministry of Transportation and Communications has since been investigating into the cause of the accident.

According to the latest report, experts found that the land of the slope was softened and damaged by underground water.

Also, the grouting construction method that failed to increase the anchoring force of ground anchor compounded the problem, and eventually caused the accident.

Experts believe that the construction contractor did follow the protocols in stabilizing the slope and in constructing the ground anchor.

However, it is difficult to evaluate the land changes underground, and it wasn't entirely the team's responsibility for not noticing that the ground anchor was not installed properly before they finished the construction.

To prevent similar tragedies from happening again, the Ministry has ordered officials to finish the review over 32 slopes on the country's freeway ground anchors by the end of June,

and the improvement projects of landslide-prone slopes are expected to be finished by 2013.