I was curious how long it's been around, and did some digging. It seems to have been launched in 2009[1] and greatly expanded between 2011 and 2013[2].

[1] https://www.lta.gov.sg/apps/news/page.aspx?c=2&id=3afz2r6kt6...

[2] https://www.lta.gov.sg/apps/news/default.aspx?scr=yes&keywor...

Singaporean here. Wow, I've never seen nor heard about this before! Thanks for sharing. Did some digging in on our local newspaper: http://www.straitstimes.com/singapore/more-locations-for-sch...

Looks like the proof of concept was started way back in 2009!