PHOENIX (AP) -- Arizona motorists must use booster seats or other restraint systems for children through age 7 who are not more than 4 feet 9 inches tall.
The new law goes into effect Thursday.
Arizona already had required that children through age 4 use a child restraint system.
Violators are subject to a $50 penalty under the latest requirements. But it wouldn't be imposed if the person later equips the vehicle with a restraint system.
Arizona legislators had blocked previous attempts to bolster the restraint law because of objections about government intrusion and cost to parents.