A 34 year old man from Annan is in a critical condition at a hospital in Glasgow following a crash between his Landrover car and an articulated lorry on Saturday morning.
It's the latest in a series of serious accidents along the A75 near Annan which has seen two people die in the past fortnight.
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Sandy Murray, of Police Scotland, was was giving evidence at the trial of a bus driver who denies killing Ryan Baird by dangerous driving.
34-year-old Christopher Peck was involved in a head-on crash with a drunk driver. His funeral has taken place in his hometown, Workington.
The arrests come weeks after a much-publicised series of appeals to mark the 30th anniversary of the 18-year-old's death.