Senior Aircraftman James Bowskill, 25, who has denied the charge, is accused of leaving the hard shoulder of the Iraqi highway as he and other Royal Air Force soldiers were taking down a checkpoint, driving across the road and crashing into a car carrying Iraqi adults.
"A civilian vehicle came along the road, under the bridge, and the Iraqi driver and passengers were surprised to see a Land Rover pull out from the hard-shoulder area, with the apparent intention of crossing the motorway, almost at a right angle," said prosecutor Captain Geoff Harding on Monday.
"There was no time for the Iraqi vehicle to avoid the collision."
Under British law
The Iraqi vehicle rolled over several times and was severely damaged, he said. Some of the five Iraqi women killed had been thrown from their vehicle by the impact, Harding said.
"It is a tragic case. Five people died. Regardless of the outcome of this case, the accused will no doubt have to live with his role in the collision for some time to come," Harding said.
Like other soldiers, Bowskill's regiment, which guards RAF bases in Britain and overseas, is required to abide by British driving laws while working in other countries. The hearing was to continue on Tuesday.
Britain, a key member of the US-led forces in Iraq, has about 9000 soldiers there, mostly in and around the southern city of Basra.