Why not shorten Svc 76 to Serangoon Int? Withdraw it? 
Ang Mo Kio got 268 to serve. But transfering many
buses to go to a place is quite troublesome. Passengers that wanted
to go Marine Parade can take 76 and transfer 43, then 76 terminates
at Serangoon Int. Although Serangoon and YCK Rd has 70 to serve but
70 makes a different route, it goes to Yio Chu Kang Ter via Yio Chu
Kang Rd, not AMK Ave 3. Then if 43 always get overcrowded, SBST can
always put some Double Deck buses. 
Route susggestion for 76: YCK Ter, remains on the same route until
AMK Ave 3 (Blk 554), then maybe turn into:
1) S'goon North Ave 1 and back to Yio Chu Kang Rd for a faster
journey to Serangoon Int, but this may drop the demand for 315, it
have to make a round then it will reach S'goon Int.
2) Withdraw 315 and 76 ply to Serangoon via S'goon North Ave 4,
then AMK Ave 3, then Ave 1 then continue with the rest of 315's
journey.
3) Loops at Yio Chu Kang Rd.
4) Serve to the former Hougang South Int then loops.
Svc 43 can continue the rest of 76's journey. 76 can ply to other
places other than Marine Parade. But Serangoon North's
transportation is good enough, they can take 70, 147 to the city,
43 to Marine Parade, any bus along AMK Ave 3 to AMK except 74e, 73
to Toa Payoh etc.
Bus services available:
Lower part, Yio Chu Kang Rd, 43, 70, 73, 76, 109, 147, 156,
317,
Aft Hougang Ave 2, AMK Ave 3, its 25, 55, 73, 74, 76, 132,
165.
Advantages: This may be able to make better links between Yio Chu
Kang & Serangoon, esp AMK MRT, elderly do not have to walk very
far just to take bus. Those who live near AMK Ave 3, upper part of
S'goon Nth Ave 1 and the middle, lower part do not have to walk all
the way to Yio Chu Kang Rd. This can make direct link between NSL
and NEL.
Disadvantages: AMK residents will not have a direct link between
Marine Parade and Yio Chu Kang.
If anyone had other susggestions, you may want to post it here. For
the 76 route changes, it could be changed anytime, do not have to
wait until CCL opens. If SBST is going to work this out and suscess
(I hope won't, at least can shorten the waiting time), SBS 352,
3860, 9181 etc may be gone, esp the DD buses.
