Police have defended the closure of the M1 which caused misery for thousands of drivers following a traffic accident.
Five people were hurt but no-one's injuries was life-threatening
The motorway was closed from Thursday morning until 2100 BST after a crash involving two lorries and a car.
Inspector Rosie Leech said there were "quite unusual circumstances" as debris was spread across both carriageways.
"A serious road traffic collision investigation scene is initially treated the same way as a murder scene until officers can prove differently."
The crash left five people injured and saw the road closed in both directions between Lisburn and Stockman's Lane.
One man was trapped in his lorry after the accident, which happened just before 0800 BST. Four people were taken to hospital.
Inspector Leech said even at 1800 BST during the evening rush hour, there were as many as 100 officers at the scene.
Traffic on the motorway came to a standstill
"We tasked photography, mapping, forensics and video cameras to collect all the evidence necessary to sustain a prosecution," she said.
Inspector Leech said they could not open one of the carriageways to ease the traffic build up because it took a long time to clear debris and the crashed lorries.
"I have anecdotal evidence from officers on the ground of people driving up to the signs, moving 'road closed' signs and cones and attempting to drive through," she said.
"The people complaining at police action, or inaction as they would see it, in failing to get the road open, are the selfsame people who if one of their loved ones was in a serious road traffic collision and we failed to investigate properly, would be the ones complaining.
"We're damned if we do, damned if we don't."