Long tailbacks caused by finishing work on the Queensferry Crossing will stretch beyond its second birthday, a motoring group fears.
Evening commuters have reported mile-long queues as contractors step up remaining tasks to complete the £1.35 billion bridge, which opened in August 2017.
The work is not scheduled to end until October and Transport Scotland has now revealed the builders will not be completely clear of the crossing until December.
It said the outstanding work was always planned for after the bridge opened, but said last year it would have a “minimal impact on traffic”.
Completion of some of the tasks, including drainage and lighting, have been put back three times, as Scotland on Sunday revealed in April. Clear-up work will take till December.
Motoring group IAM RoadSmart predicted a “summer of potential hold-ups and frustration for drivers”.
Traffic restrictions, such as lane closures to enable the work to go ahead overnight, are usually not imposed until 8pm or later, but regular users said significant delays were now more frequent.
One frustrated Fife commuter said: “My journey home used to take roughly 30 minutes, leaving Edinburgh about 8:40pm. For the past several weeks that has been extended considerably.
“If you are unfortunate with your timing, the result is a 15 to 20 minute wait in a queue of traffic just to get onto the bridge, which is then at a crawl nose-to-tail.”
IAM RoadSmart policy and research director Neil Greig said: “Most Queensferry Crossing users must have been hoping that we would now be seeing an end to snagging works and any related delays. Accurate and timely information on journey time predictability are the key for us. Whilst Transport Scotland are being open about the works, they are still being vague about the likely delays and timings.”
Transport Scotland said only one complaint had been received about the delays, and lanes were closed only once traffic was free-flowing after the evening peak.
Its spokesman said: “From the start of May, nightly traffic management has been in place to facilitate snagging and finishing work. This is expected to continue through until the end of summer 2019.
“The configuration of this traffic management is dependent on the works planned by the contractor, and as such has potential to vary on a regular basis. This work has been scheduled overnight to minimise disruption for road users.
“Our contractor, FCBC, is progressing snagging and finishing works, which are scheduled for completion later this year – with full demobilisation expected by the end of the year.”