A section of the Snake Pass has been closed following a crash involving a motorcycle.
Derbyshire Police said part of the road had been shut near the junction with the A6013 turn off for Bamford.
The force said emergency services were in attendance and the road was expected to be shut for some time.
It advised motorists to use alternative routes.
The road had been closed for ground investigation works which are set to last until 3 July but had reopened temporarily for the weekend.