The accident happened shortly before 2 a.m. Sunday in Meriden. Police say two adults and three children were in a car stopped at a traffic signal when an SUV rear-ended them.
A 5-year-old girl and her 8-year-old brother were killed and their parents are hospitalized. A 12-year-old child also is hospitalized in intensive care. Police believe the 12-year-old child also is a family member.
The victims' names haven't been released.
Twenty-nine-year-old Israel Gonzalez of Meriden was charged with reckless driving and other crimes. He's detained on $1 million bail. It's not clear if he has a lawyer.
Police believe alcohol and speed were factors in the accident.