Hi there! It is NOT mandatory to dismount and push our bicycles. It is encouraged if there are many pedestrians crossing at the same time or at places where high human traffic exists, like at bus stops.

You can read LTA's reply here: https://www.bwss.sg/news/2018/1/18/wf7t1s6yrjqo3h324iynw5ygh7z0lf