The trial of the organiser of a fireworks display held on the night of a fatal pile-up on the M5 will begin on Monday, a court heard.
Geoffrey Counsell, 51, is charged with failing to ensure the safety of others, contrary to the Health and Safety at Work Act.
Seven people died in the crash, which involved 34 vehicles.
Anthony and Pamela Adams, Maggie and Michael Barton, Malcolm Beacham, Terry Brice and Kye Thomas were killed in the incident on November 4, 2011.
More than 50 other people were injured.
Counsell, of Ashill in Somerset, was operating a fireworks display in a field close to the motorway, at Taunton Rugby Club, at the time.
He pleaded not guilty to breaching health and safety regulations and was due to stand trial this morning at Bristol Crown Court.
But Mr Justice Simon told the court that the case would not open until Monday, with legal discussions expected to last for the rest of the week.
A jury panel will be selected from 43 potential jurors, who were addressed by the judge this morning.
Mr Justice Simon said: "This case is a health and safety prosecution arising out of a fireworks display on the 4th of November 2011 at Taunton Rugby Club and a series of collisions that took place on the northbound carriageway of the M5 motorway, just north of junction 25.
"This is a very serious matter and you must treat it very seriously."
The charge alleges Counsell failed to ensure he operated the firework display so as to ensure, as far as was reasonably practicable, that others who might be affected were not exposed to risks to their health and safety.
The trial, expected to last up to six weeks, will be prosecuted by Peter Blair QC and Anna Vigars. Counsell is represented by Adrian Darbishire QC and Simon Antrobus.
Mr Justice Simon warned the potential jurors the case could last up to six weeks.
"This trial is scheduled to last until shortly before Christmas," he told them.
"Jury service is the only duty required of citizens now. It is an important public duty."