NUS stands for National University of Singapore. The A1 route is named after the internal shuttle bus A1 route, which goes through all the major faculties on campus in a loop. It is common to see joggers and cyclists taking the hilly route as part of their cardio workout routine. The mix of joggers and cyclists mainly consist of the undergrads, graduate students, and occasionally the residents in the nearby residential areas.
NUS A1 Route
to set its location.