Petaluma police said a woman who drove through a red light and crashed her car into the back of two vehicles Tuesday night might have had a toxic, usually lethal amount of alcohol in her blood.Police believe Ambu Lara Ford, 40, of Petaluma had a blood/alcohol level of 0.50 percent, more than six times the legal limit, Sgt. Ken Savano said. She has no prior DUI arrests. A citizen saw Ford drinking from a bottle of hard liquor in the parking lot of the Round Table Pizza restaurant in the 1500 block of East Washington Street around 7:45 p.m. Tuesday, Savano said.Ford finished the bottle and fell to the ground as she tried to get into her red Honda Accord, the citizen told police.Savano said the citizen unsuccessfully tried to keep Ford from driving then called 911 on her cell phone. The call went to the California Highway Patrol and was transferred to Petaluma police. The citizen said Ford was weaving within traffic lanes on eastbound East Washington Street, Savano said.At the same time, other police dispatchers received reports of a three-car collision at the intersection of East Washington Street and Sonoma Mountain Parkway three blocks from the pizza restaurant, Savano said.Police at the scene learned a DUI driver failed to stop at a red light and struck the rear of two vehicles waiting at the light, Savano said. The driver of one of the vehicles was treated at a hospital for an injury and released.Ford was allegedly found to be extremely intoxicated and investigators believe her blood/alcohol level was greater than 0.50 percent, Savano said. She was admitted to a hospital because of her level of intoxication and was arrested for felony DUI, Savano said. Because she was admitted in the hospital, she was released with a citation to appear in court, Savano said.Police are investigating the collision, where Ford purchased alcohol and her driving history.