It does makes sense for 170 to be controlled by HGDEP as Queen
St is only 10.3 km away from HGDEP, 13 minutes drive via Upper
Serangoon.
To ARBP is 11.8km and 15 minutes drive. To BBDEP is 13,6 km, 19
minutes drive. To AMDEP is is 13.6km , 15 minutes drive
too.
For those coming out from JB, AMDEP will be a better option. So
i think 170 should be controlled by HGDEP and AMDEP.
Actually,HGDEP and BBDEP can both control 170 together because
BBDEP is actually neare to JB than AMDEP.Btw what is the first bus
timing from Larkin Terminal?