Hi Bro Frado, since you ride bike across the causeway daily, you may want to take heed of what's written in this http://www.allsingaporestuff.com/ar...es-msian-bikes-look-out-or-risk-tyre-puncture
Not sure about the authenticity, but there's no harm to be cautious.
Thanks! Not sure what is the intent of these people putting nails there. If these are just to prevent the person behind from bumping their tyres onto their rear them while being jammed at checkpoints then these people really very petty, and also very evil hearted for intentionally causing damage or hurt. Considering how packed the checkpoints are it is inevitable that there will be the occasional tyre bumps from the biker behind, or even to bump into the biker in front. Unless one is purposely trying to provoke, just treat it as an innocent accidental bump lah. Life is so short, air so polluted at customs, why still add such things to it?