Since SMRT has put up a tender for 66 new 12m buses, it looks
like these will be the ones to replace the UD. If that's the case,
then SMRT wouldn't be extending the lifespan of the UD, which are
scheduled for withdrawal in 2010.
The lifespan for public buses is still at 17 years. SBST got
permission from the LTA for a 2 year extension because of
insufficient new buses to replace the outgoing ones. This could be
because of the the new ruling which requires all new buses to be
Euro IV compliant.