The 5-week-old baby was found in the car seat in the middle of a road about 1 a.m. by city fire department officials, who took the infant to a hospital, The Arizona Republic reported. The child was "perfectly OK," police Officer James Holmes said, and was placed in custody of state Child Protective Services, the Phoenix newspaper said.
The 19-year-old mother, Catalina Clouser, was arrested.
She allegedly had been smoking marijuana at a nearby park with her boyfriend, and they left the park to buy beer. The boyfriend was arrested on aggravated DUI charges while on the way, Holmes said, and Clouser went to a friend's house where she allegedly smoked more marijuana.
Clouser later left the house with the baby asleep in the car seat and didn't realize her child was missing until she got home. She called her friends and asked them to trace the route she had taken, the Republic said. The friends encountered the officers who had already found the baby, and Clouser was taken into custody when she arrived soon after, Holmes said.