FREMONT, Calif.—A 19-year-old woman has been killed and a 3-month-old boy she was carry has life-threatening injuries after they were struck by a vehicle on New Year's Eve in Fremont.

Authorities say Ashley Capuchin was killed around 10 p.m. Tuesday after she got into an argument and stormed out into a busy thoroughfare with the baby. Capuchin, her 17-year-old sister and the baby were all hit by a vehicle as they crossed a median.

Capuchin was taken to a hospital where she died. The baby was listed in critical condition. The 17-year-old sister was treated at a hospital for injuries that were not life-threatening.

The 64-year-old driver stopped after the crash and was cooperative. Authorities say there was no sign of alcohol or drugs being involved.