Height, Not Age: The law depends strictly on height, not age. A 9-year-old under 1.35m must use a booster seat, while a tall 6-year-old over 1.35m may use a standard seat belt. Approved Standards: Car seats must carry recognized safety certifications like the European ECE R44/04 or ECE R129, American FMVSS 213, or Japanese JIS D0401. Penalties: Drivers face an on-the-spot fine of S$120 and 3 demerit points. Court convictions can lead to higher fines up to S$1,000 or imprisonment for first-time offenders.