Constructing highway on soft soil is very challenging because of the difficulty to carry out compaction of the soil. In order to construct a long lasting pavement, it is important for the soil layer to be strong to support heavy vehicles passing through the facility. One way of strengthening the soil or subgred is using Bakau, one of mangrove trees species. Mangrove trees grow where no tree has grown before and they can survive inundation by salt water twice a day, and in "soil" which is unstable.
In the following picture, Bakau trees is widely used in construction.
Instead of driving the Bakau vertically into the soil which is quite often for construction building foundation, Bakau is placed horizontally especially near man-made structure such as concrete drain to prevent differential in settlement once the highway is completed and open to traffic.