Massachusetts' new booster seat law to keep kids safe went into effect Thursday. The law requires children under the age of eight and under 57 inches tall to ride in either car seats or booster seats.

The old law required children under 5 and weighing 40 pounds or less to be in a car seat or booster seat that positions the safety belt across the child's waist and shoulder, rather than halfway up the midsection or neck.

The new law replaces the weight requirement with a height requirement. Under the current law children are required to be in car seats until they turn 5 or weigh at least 40 pounds.

Violations of the law could lead to a $25 fine.