My colleague is an easy-going fellow and it is too bad that he was involved in a minor accident which he was at fault. Since the damages to both vehicles were not major, he offered and the other party accepted a private settlement. Both of them exchanged their personal particulars and he thought the inconvenience was over after his car was repaired.
When his insurance company called to inform of a claim against him for the accident, he was flabbergasted that the other party had not honoured the private settlement. He could not prove that the private settlement had taken place as they did not sign any agreement in black and white. It turned out to be an expensive lesson as his No Claim Bonus on his insurance premium was affected.
These days, our group are equipped with a private settlement form in our cars so as to prevent such an unpleasant experience from recurring. I like this one (130 kB PDF) better than the current A4-size form on Income website https://income.com.sg/forms/claims/.
Do be prepared as you do not know what kind of people you may bump into ... or conversely, may bump into you ....
Update - Effective June 1st 2008, the Motor Claims Framework (MCF) will require motorists to report the accident to the insurer within 24 hours or by the next working day regardless of any private settlement arrangement. Motorists may indicate in the report that a private settlement was reached.