Section of Ring Way in Preston closed for investigation into road collapse
The road will remain closed until the cause of the sinkhole has been found.
Engineers from Lancashire County Council are currently at the scene while investigation work takes place.
A council spokesman said: A lane closure was put in place on Thursday due to a depression emerging in the road surface, and work is now urgently needed to find the cause and make a repair.
"Until investigations have taken place it is not known when Ring Way will fully reopen.
"A diversion will be signed via Lawson Street, Walker Street, Lancaster Road, Melling Street and North Road. A temporary bus stop will be in place on Lawson Street for passengers who would like to get off before reaching the bus station."
Rob Wilson, area highways manager for Lancashire County Council, added: "We're sorry for any disruption due to the need to close Ring Way this weekend, however it's vital that we investigate the cause of the road collapse.
"Unfortunately we can't say when we'll be able to reopen the road until we've found the cause of the problem, however we'll be working throughout the weekend as necessary to try to get it repaired as quickly as possible."