For services 139 and 155, cannot use the "In" and "Out" cards.
For example, service 139 passengers along Jln Bahagia, when they
see the "Out" card, they will be confused: Out to where? Toa Payoh?
Bt Merah? That's why the buses have an extra side desto at the
front to indicate where they are terminating, instead of using the
"In" and "Out" cards.
For services terminating at St. Michael's, beside the "In" and
"Out" cards, they also use red and white side destos.