A six-year-old boy has died from injuries sustained in a multi-vehicle crash in Hants County, N.S.

Police say the crash occurred shortly before 11:30 a.m. Tuesday on Highway 101 between exits 6 and 7, near Falmouth.

A total of four vehicles were involved in the crash including a minivan, a motorhome, a car being towed by the motorhome, and a transport truck.

Police say the vehicles involved had been stopped on the highway by a construction crew, but the driver of the transport truck failed to stop in time and rear-ended the minivan in front of him, causing it to collide with the motorhome.

A 38-year-old woman and three children – two girls aged three and eight and a six-year-old boy – were taken to hospital. Police say they were in the minivan at the time of the crash.

The little boy and the eight-year-old girl were airlifted to the IWK Health Centre in Halifax with life-threatening injuries while the others were taken by ambulance to the Hants West Hospital.

RCMP Staff Sgt. Dan Austin confirmed to CTV News that the boy has since passed away in hospital.

He says the eight-year-old girl remains at the IWK Health Centre in stable condition.

The 59-year-old driver of the transport truck was also taken to Hants West Hospital with non-life-threatening injuries and later released.

Police say the Montreal man is due to appear in Windsor provincial court on Sept. 3 to face a charge of dangerous driving causing death.

He was originally charged with dangerous operation of a motor vehicle causing bodily harm, but the charge was upgraded Wednesday after the boy passed away.

Police believe speed was a factor in the collision.

The occupants of the motorhome were shaken but not injured in the crash. They are from Halifax and were travelling to the Annapolis Valley for a vacation.

The highway was shut down in both directions for several hours Tuesday while police investigated the scene. It reopened to traffic around 5 p.m.

The busy stretch of highway, which serves as the main route to the Annapolis Valley, has been flagged as a hazard in the past. Most of the highway has been twinned but the stretch of road where the vehicles collided remains a single lane.

The MLA for the area says, while a number of factors could have contributed to the incident, a twinned highway could have reduced the risk.

“One of the benefits to doing work like this, if it was twinned one lane you’d reduce your speed as we have in other places, but you’d still have one lane to pass through on the twinned section, and the oncoming traffic would be irrelevant because you wouldn’t be anywhere near that,” says Chuck Porter, MLA for Hants West.

Austin says the crash remains under investigation.

With files from CTV Atlantic's Kelland Sundahl