Three siblings and a family friend driving to a dance competition were killed when a pickup truck slammed into the back of their vehicle on a Texas road on Friday, authorities said.

The mother of the three siblings — identified Monday as Tiffany Williams, 17, Michael G. Williams, a middle-schooler, and Danielle Williams, 12 — had stopped to make a left turn off Texas Highway 21 in Bastrop, about 30 miles southeast of Austin, when a 2004 Ford F-150 crashed into the rear of the 2019 Toyota Corolla, authorities said. The children, who had all just traveled in from Huntsville two hours away, were pronounced dead at the scene, authorities said.

“All were traveling with the mother of the siblings to San Antonio to watch an older sibling perform with the Huntsville High School Grenadier Guard Drill Team at National Competition,” district officials said in a statement.

A family friend, 19-year-old Peyton Mackenzie Irwin, a graduate of Huntsville High School — where Tiffany was enrolled as a junior — also died in the wreck.

The mother, Pamela Mary Williams, 53, was rushed to a hospital in critical condition, according to Texas Highway Patrol officials. She remained in a coma as of Saturday, the Austin American-Statesman reports.

The owner of a nearby gun store, Dan Whitaker, told the newspaper that video surveillance from his store shows that the pickup truck appeared to have plenty of time to avoid the crash before rear-ending the group’s vehicle, which had its blinker on while waiting to turn.

The truck was traveling 58 mph at the time of the collision and did not brake until 0.6 seconds prior to impact, suggesting the driver was distracted, possibly by a cellphone, according to the Texas Department of Public Safety.

The driver of the truck — Juan Jose Hernandez, 18 — and his passenger, Jacqueline Gaspar, 18, of Houston, were not injured in the crash. An investigation is ongoing, authorities said.

School officials, meanwhile, arranged for additional school personnel, including counselors and psychologists, to help students and staffers cope with the deaths beginning on Monday.

“We encourage you to be especially sensitive and prepared to offer support to your child during this time,” district officials said in a statement. “Over the next few days, you may wish to encourage your child to express his or her feelings and listen attentively.”

The district has also organized a weeklong effort to memorialize the victims with designated “color days” to denote the “favorite color of each friend” involved in Friday’s fatal crash, starting on Monday with blue and ending the week with “hornet green” on Friday.

A GoFundMe page was also organized by a family friend to help offset funeral costs for the siblings and medical expenses for their mother. More than $15,000 had been raised as of Monday, according to the website.