Completion of the new £208m section of smart motorway on the M60 and M62 has been delayed, with the scheme not fully open until next summer.
Highways England had originally said that the scheme would be finished this autumn.
The Government-owned company said that a phased opening of the all lane running scheme will start this autumn, with the removal of temporary narrow lanes on some sections, followed by the opening of the former hard shoulder and the introduction of variable speed limits.
However, it added that ‘other issues such as needing to relocate unrecorded utility pipes and carrying out additional maintenance work has meant that part of the scheme will need to continue into 2018’.
Temporary 50mph speed limits will remain in place in each section until that section is completed.
The hold-up follows a delay to the full opening of the M3 smart motorway, where temporary speed limits were needed as new technology was commissioned.
Jon Stokes, senior project manager at Highways England, said: ‘We will be able to begin a phased opening of the new smart motorway scheme this autumn – benefiting the 180,000 drivers who use the route every day.
‘Nearly 600 people are currently working to complete the project and we will open each section along the route as soon as possible.’
Highways England said the scheme is its most complex smart motorway project, affecting the second busiest motorway in the country and covering 13 junctions.
It said to minimise disruption it worked hard to keep all of the lanes open in each direction during the day but this has meant major construction work could only be carried out overnight, affecting the overall duration of the project.
The full scheme stretches between junction 8 of the M60 near Sale and junction 20 of the M62 near Rochdale.
The phased opening over the next few months will see the removal of the temporary narrow lanes on the M62 starting in October, and between junctions 8 and 10 on the M60 later in the autumn.
The new technology will then be tested to ensure the 100 traffic sensors which have been installed along the 17-mile route are working effectively, before the new electronic variable speed limit signs on these sections are switched on by the end of the year.
The extra lanes on the M62 are also due to open in time for the Christmas getaway.
The temporary narrow lanes are due to be removed between junctions 15 and 18 on the M60 in early 2018, and from the final section of roadworks – on a 5-mile stretch of the M60 between junctions 10 and 15 – in spring 2018.
Variable speed limit signs are due to be switched on between junctions 10 and 18 by summer 2018.