La Cañada Flintridge Crash

Flowers were left at the scene Thursday morning as engineers study the structural integrity of the gaping hole in the front of the Flintridge Bookstore and Coffeehouse.  (Al Seib / Los Angeles Times)

Dana McDermott, right, manager of the Flintridge Bookstore and Coffeehouse, and server Melissa Watkins survey the damage left by the big rig that smashed into the establishment. “I thought we were gonna die,” Watkins said.  (Al Seib / Los Angeles Times)

Dana McDermott, left, manager of the Flintridge Bookstore and Coffeehouse, hugs employee Rob Gibbs in back of the establishment.  (Al Seib / Los Angeles Times)

Television crews interview 16-year-old Malia Mailes in front of La Cañada High School after they learned she completed a PowerPoint production detailing the danger of a hypothetical truck crash at the same intersection as Wednesday’s actual crash.  (Al Seib / Los Angeles Times)

A big rig descending Angeles Crest Highway lost control at Foothill Boulevard in La Cañada Flintridge. A Palmdale man and his daughter were killed, authorities say.

Truck driver arrested in deadly La Cañada crash  (Luis Sinco / Los Angeles Times)

A firefighter pauses from rescue work. The truck’s driver suffered minor injuries and was taken to a hospital, authorities said. The cause of the wreck was under investigation. A passenger in the truck was not hurt.

Truck driver arrested in deadly La Cañada crash  (Luis Sinco / Los Angeles Times)

The carrier slammed into a bookstore and came to rest in a nearby nail parlor.

Truck driver arrested in deadly La Cañada crash  (Luis Sinco / Los Angeles Times)

An injured motorist receives aid.

Truck driver arrested in deadly La Cañada crash  (Luis Sinco / Los Angeles Times)

Paramedics take a woman to an ambulance. Twelve people were injured, three critically.

Truck driver arrested in deadly La Cañada crash  (Luis Sinco / Los Angeles Times)