Highways England will close the M27 tonight between junctions 3 and 4 at Romsey and Southampton for a £19million bridge repair.
The closure begins at 9pm tonight and doesn’t end until 5am on Monday morning.
The travel chaos has been described as “the biggest traffic diversion ever in the country” by Hampshire’s fire and rescue service.
Westbound drivers will be sent on a hellish diversion to Andover on the A303, before heading all the way to Salisbury and back to Southampton on the A34.
Smaller vehicles will be able to use more local and rural roads, but heavy goods vehicles will have to drive 58 miles before re-joining the motorway.
It will cost lorry drivers an extra £35 in fuel, according to the Road Haulage Association.
A spokesman for the RHA said: “At a time when a typical hauliers’ profit margins are one to two per cent, the impact of this diversion will hit hard.
“Delivery times will also be affected and many drivers will be forced to park up to take statutory rest breaks on the route, with some even needing to park up overnight.
“It is also inevitable that drivers will be tempted to use other shorter routes, some of which may not be suitable for lorries.”
And the traffic hell won’t just affect motorists this weekend, with two more weekends of closures to follow in the next 12 months.
Closures will also take place next year between April 26 and 29 and October 18 and 21 2019.
Highways England is rushing to fix the A3057 Romsey Road Bridge over the motorway after “severe” cracks were spotted on the structure used by thousands of vehicles every day.
Route sponsor John Henderson said: “Completing these key phases of work at the weekend means that restrictions can be kept to a minimum at other, busier, times and we have chosen diversions that are the most suitable for the type and volume of traffic that usually uses the M27.”