A van driver was seriously hurt and an HGV driver suffered minor injuries on the A66, police say.
One person was airlifted to hospital following the crash, the Great North Air Ambulance says.
A timeline for work on the road, which runs between Penrith and Scotch Corner is yet to be released.
Plans for the Scotch Corner outlet were approved in 2016 with an original opening date of late 2018.
Chancellor Rachel Reeves says the decision has been handed over to the Department for Transport.
Scotch Corner Designer Village was granted planning permission in 2016 and is still to open.
Plans to widen the A66, which links Scotch Corner and Workington, are currently on hold.
Some homes in north-east England and Cumbria could be without power until Sunday evening.
The three men were arrested as part of a joint operation including West and North Yorkshire Police.
