For your info, these stretches of the expressways you mentioned
are normal roads before, the bus stops there have existed then if
I'm not wrong.
AYE is formerly called Ayer Rajah Rd (between Alexandra Rd and
Clementi Rd) and Upper Ayer Rajah Rd (between Clementi Rd and
Jurong Town Hall Rd).
Part of PIE used to be Paya Lebar Way, Jln Kolam Ayer, Jln Toa
Payoh and Whitley Rd.