I am sorry. I cannot make sense with the section between Bishan
and Lavender Street. It is totally off, and it seems to duplicate
the route of bus service 13.
I agree that between Queenstown station and Lavender station,
bus service 51 duplicates the other bus services that also call at
Queenstown station. Nonetheless, this enables a direct bus
connection between Clementi area and the City area. If we skip this
section to reduce duplication, there would be a loss of direct bus
connection between Clementi and the City.
Clementi area has quite an ample services towards the city.
7 , 14 , 105, 106, 143, 175 --> Orchard/Suntec
7, 197, 175 --> Bugis
196 --> CBD
143, 147, 166, 197 --> Chinatown
Other wise, MRT is another alternative.
The cut off of 51 doesn't really duplicate much of 13, it
skipped Potong Pasir area and 13 do serves Bishan North and AMK
residents, different bus services serves different places, doesn't
mean that duplication will affect their demands.
For 110, even with duplications, 159 still serves their own
catchment areas, 110 is just for Sengkang West, AMK, Bishan,
Whampoa.
Duplicating 156 is not a problem, Thomson area has quite a low
demand during off peak, and different service serves different
areas, giving them alternatives is a good way too.