Drivers travelling through North Yorkshire are being warned to expect disruption due to the temporary closure of a large stretch of the A1.
Two bridges are being demolished as part of the major scheme to upgrade the stretch between Dishforth and Leeming to motorway standard.
The road was closed from junction 49 to 60 at 1800 BST on Saturday and will stay shut until 1300 BST.
The same closure will be in place the weekends of 16/17 April and 7/8 May.
Diversion routes are in place.
Six miles longer
The Highways Agency planned the closures to enable workers to demolish Cowfold Bridge and the old Londonderry Bridge.
A replacement bridge at Londonderry is already in place and is expected to be in operation by early June.
Project manager Arun Sahni said: "We have worked hard to plan this work to cause as little disruption as possible, but we know that the diversions will cause some inconvenience, particularly until the replacement Londonderry bridge opens.
"We are advising road users to be aware of the diversion routes and allow extra time for their journeys. The diversion routes for long-distance traffic will add approximately six miles to their journey.
"We have avoided closing the A1 during the Easter and Royal Wedding weekends, as we know the roads will be busy with people travelling on holiday or to spend time with friends and family.
"These works are an important stage in the scheme to upgrade this stretch of the A1 to motorway standard. The project is progressing well and is due to be completed in spring 2012."