Mode 3, the motorway will be closed to traffic. Full bore of the tunnel will be
used to mitigate the stormwater. Once the FDS system confirm the need to
activate the mode 3 operation. Sufficient time will be allocated to allow the
closure of tunnel from traffic, evacuate all passenger vehicles before the
automated water gates are activated to occupy the flood water. The anticipated
duration of switching to from mode 2 to mode 3 is estimated to be about one
hour. After the flood recede, the targeted duration for tunnel reopening is
minimum of two days to enable for flood dewatering, cleaning and
reinstatement the TMCS