Delays for drivers using the Queensferry Crossing are forecast to continue over the weekend after commuters suffered long queues in tonight's rush hour.
More motorists are expected to flock to the new bridge, including those who have not had a chance to cross it since it re-opened permanently yesterday.
The warning came as queues built up on the M90 towards the bridge for five miles southbound and three miles northbound.
There were also a tailback of several miles on the A904 eastbound approach to the crossing into West Lothian.
The Scottish Government's Transport Scotland agency, which is in charge of the £1.35 billion bridge, said there could be heavier traffic both this weekend and next.
Its spokesman said: “The Queensferry Crossing is now in only its fourth full day of operation, having been open on 30 and 31 August, closed for events from 1-5 September and reopened on 7 September, so we are still very much in the initial phase.
“It normal that major bridges experience significant extra traffic flows on the initial opening days as people come to see them for the first time.
"It is also normal for this to wear off soon, although the first couple of weekends may also be busier than usual particularly during spells of good weather.
"We recommend people plan their journeys in advance and check [trunk road information service] Traffic Scotland for the latest position on the roads before starting their journey.”