You are driving your 6-year-old niece, who is 50 inches tall. How must she ride under New Hampshire law?

Correct answer: In a child restraint, because she is under 7 years old and under 57 inches tall

Why

A child restraint holds a small child in the correct position in a crash in a way that an adult belt alone cannot. New Hampshire law requires a child restraint for a passenger under 7 years old who is under 57 inches tall, and the restraint must be used as its maker directs, including its height and weight limits. State law also requires a rear-facing restraint for a child under 2 (RSA 265:107-a, I-c), a rule that the manual does not mention.

Verified against New Hampshire Driver's Manual · Child passenger safety laws · p. 18