Provincial police say two children, aged four and six, remain in critical but stable condition Friday, after being airlifted from the site of a Thursday morning crash between a Volkwagen GTI and a horse-drawn buggy on Highway 9, just south of Clifford in Minto Township.

Flattened grass at the site of a collision between a horse-drawn buggy and car near Clifford, Ont., in Minto Township. (Colin Butler/CBC News)

Aden S. Martin, who owns a farm in Huron County, told CBC News that Mark Streicher, 45, his wife and eight children weren't far from their home on Highway 9 when the buggy was struck shortly after midnight on Thursday morning.

Martin said the wooden buggy shattered into a cloud of splinters upon impact with the car, which was also travelling in the northbound lanes of Highway 9 at the time of the crash.

Other residents in the area confirmed to CBC News that Streicher and his wife have 10 children and the collision happened almost right in front of the family home.

Wellington County OPP said the two children, aged four and six, were airlifted to hospitals in London and Hamilton. They are in critical but stable condition.

The rest of the family members did not suffer serious injuries and have all been released from hospital.

One neighbour said he often got fresh eggs from the Streicher family, who are Mennonites.

Safety issues around horse-drawn vehicles Old order Mennonite groups generally avoid using modern technologies like cars and electricity, although those choices can vary by group. Generally slow-moving vehicles, like horse drawn-buggies, should have a bright orange triangle displayed on the rear of the vehicle, signalling they are travelling at 40 km/h or less. But according to the Ministry of Transportation, "people whose religious beliefs do not permit them to use the sign" are exempt from attaching the triangle. The ministry does require that the back of the vehicle should be outlined with reflective tape visible from at least 150 metres away.

Investigators said a 2012 Volkswagen GTI was travelling northbound on Highway 9 when it collided with the buggy that was travelling in the same direction.

Tire tracks spotted by CBC News indicate the car left the highway.

After the collision, Martin collected pieces of wood from the buggy, as well as the family's belongings, including a shoe and a pink disposable diaper. Martin also had a piece of the VW symbol from the vehicle.

Provincial police say both the driver, Adam Leggett, 29, of Stoney Creek and the horse were not hurt in the crash. Police have not laid any charges.

It isn't known if the buggy involved in the crash had a slow-moving vehicle sign or reflective tape affixed to it.