You don't need to change route between Yishun and BPJ as that's
where it is unique... from Upp Bukit Timah onwards you get
alternatives.
171 at best can change from Beauty World onwards, as you still
may want to maintain direct link b/w Upp Bukit Timah and BPJ town.
No other service except 963 from Hillview onwards.
Another way is 171 terminates or loops at Petir/BPJ ring road
and 41 gets extended to loop at Petir/BPJ ring road as well... this
way 41 can be made more useful and cover for missing link of 171
between Upper Bukit Timah and BPJ town.
Svc 171
Yishun - Bukit Panjang (Loop)
via
Yishun Ave 5, Sembawang Rd, Mandai Rd, Woodlands Rd, Upp Bukit
Timah Rd, Bukit Panjang Rd, Jelebu Rd, Petir Rd, Pending Rd, Bukit
Panjang Rd, BKE, Mandai Rd, Sembawang Rd, Yishun Ave 5
Svc 41
Jurong East - Bukit Panjang (Loop)
via
Jurong Gateway Rd, Jurong East Ctrl, Toh Guan Rd, Toh Guan Rd East,
Toh Tuck Ave, Bukit Batok East Ave 3, Toh Tuck Rd, Jalan
Jurong Kechil, Upp Bukit Timah Rd, Bukit Panjang Rd, Jelebu Rd,
Petir Rd, Upp Bukit Timah Rd, Jalan Anak Bukit, Upp Bukit Timah Rd,
Jalan Jurong Kechil, Toh Tuck Rd, Bukit Batok East Ave 3,
Toh Tuck Ave, Toh Guan Rd East, Toh Guan Rd, Jurong East Ctrl,
Jurong Gateway Rd
Svc 973
Bukit Panjang - Marina Centre
via
Bukit Panjang Rd, Pending Rd, Petir Rd, Dairy Farm Rd, Upp Bukit
Timah Rd, Dunearn Rd, Scotts Rd, Orchard Rd, Bras Basah Rd,
Raffles Boulevard
Raffles Ave, Stamford Rd, Orchard Rd/Penang Rd/Somerset Rd,
Grange Rd, Orchard Link, Orchard Turn, Orchard
Boulevard, Scotts Rd, Bukit Timah Rd, Upp Bukit TImah Rd,
Dairy Farm Rd, Petir Rd, Pending Rd, Bukit Panjang Rd