One witness told CNN affiliate KGTV he was changing the oil in his car when he witnessed the gruesome crash.
"There's no words to really describe it. I mean, just seeing that up close and personal, it's kind of traumatizing in a way," Edwin Esparza said.
Oceanside police said the woman, Esteysi Sanchez, 29, was driving home around 6:20 a.m. Monday after a night of drinking. She started to swerve on Mission Avenue and struck a pedestrian, police said.