The tragic accident occurred around 10:50 a.m. when the driver sped through the 20400 block of West Califa Street, ran a stop sign and lost control of the SUV between Oso and Keokuk avenues.
According to witnesses, after the Rav 4 ran the stop sign, the driver swerved to miss another car, flipped over and slammed into a parked Ford F-150 pickup truck.
The two adults were pronounced dead at the scene, and the young girls were taken to Northridge Hospital Medical Center where they are listed in critical condition.
"Speed is the primary factor in this," said LAPD Capt. Jeff Bert of the Valley Traffic Division. "You couldn't have flipped a car without going a significant rate of speed."
"It's frightening to see the danger that happened here, that car could have easily launched into a household and killed somebody that was sleeping inside," said Andrea Weston of Woodland Hills.
According to Valley Traffic police, there have been nearly 40 traffic deaths throughout the San Fernando Valley in 2012 alone. Authorities say this number is already slightly higher than the number of people killed in car accidents in 2011.
Consequently, San Fernando Valley authorities are urging drivers to slow down.
"The San Fernando Valley has big wide open streets and tons of drivers, it's speed and drinking that kills," said Bert. "While there's no indication there was drinking involved, this is a speed incident."