Three members of a family from Massachusetts, including a 5-year-old girl, were killed Tuesday night when their van overturned on a toll road near Walt Disney World, according to the Florida Highway Patrol.

Five other family members were also in the van and were rushed to the hospital, one of whom is an 11-year-old boy who sustained “extremely critical” injuries, officials said.

The three killed in the crash were 41-year-old Julie Smith of Whitman, her 76-year-old mother, Josephine Fay of South Weymouth, and her 5-year-old daughter, Scarlett Smith.

The crash occurred at 5:30 p.m. on State Road 429, according to FHP Lt. Kim Montes.

Montes said that as traffic had begun to slow, a 26-year-old man driving a pickup truck rear-ended the family’s van at full speed and turned it over onto its side. The three family members who were killed were all seated in the far back of the van.

The truck driver also hit two other cars, but neither he nor the drivers of those cars were injured. Montes said that investigators have yet to determine exactly how fast the truck was going, but the posted speed limit is 70 miles per hour.

“Everybody’s just in shock based on the whole situation,” Montes said.

The surviving family members, which include the father, grandfather, a 10-year-old girl and Scarlett’s twin sister were all treated for minor injuries, Montes said. The father and grandfather remain in the hospital.

The 11-year-old boy was initially pronounced dead at the scene, but first responders found a heartbeat and rushed him to the hospital, Montes said. As of Tuesday afternoon he was on life support.

Montes said that the man driving the truck stayed at the scene and did not show any signs of impairment. He also complied with a voluntary blood draw, the results of which are expected to return in eight to 10 weeks.

According to Montes, charges are pending and will be presented at the end of the investigation, which she said typically takes 180 days.

With the exception of the father, all family members were wearing seatbelts or child restraints at the time of the crash, officials said.

On Wednesday, Whitman-Hanson Regional School District Superintendent Jeffrey Szymaniak said in a statement that each school has “activated its crisis team” and that counselors will be available to assist any student or employee who needs them.

“This is a tragedy, and I believe I express the sentiments of all families, students and employees of the Whitman-Hanson Regional School District in saying that we mourn together during this incredibly difficult time,” Szymaniak said. “I encourage all families to have honest and open conversations with their children. We have activated all the resources at our disposal, and we will come together as a community to support each other and support our students who have suffered this terrible loss.”