The £330,000 revamp of one of Norwich's busiest roundabouts has been criticised by a cycling campaign group.
But bus bosses said the new scheme is already speeding up journey times for their passengers.
Weeks of work on Norfolk County Council's changes to Grapes Hill roundabout recently came to an end.
But Norwich Cycling Campaign, which had raised concerns at an earlier stage of the scheme, said the changes cause "a big problem" for pedestrians and those riding bicycles - because they have to share the same space.
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The group said the scheme's design now dissuades cyclists from using the road and roundabout, but the shared use footpaths/cycleways they are encouraged to take instead are "totally unfit for purpose".
Sections of the shared route on Convent Road, connecting to Unthank Road, have been widened.
But the campaign said the shared path narrows to a pinch point close to the new crossing, making it hard for bicycles to get past, especially if people are queuing for the crossing.
And they said the shared use pavement which leads to Earlham Road past the Temple Bar pub has several blind corners. They warned "a conflict at that bend seems inevitable".
Derek Williams, from the Norwich Cycling Campaign, produced a ride-through video critiquing the new scheme.
He said: "It might work well for traffic, but pedestrians and cyclists have a big problem.
"The improvements to the Chapelfield crossing are superb, this is what high quality cycling infrastructure looks like.
"However, the rest of the scheme falls well below the level of provision we need and have a right to expect."
On the shared path in Convent Road, he said: "This is totally unfit for purpose and indeed, the design is counter to the government’s national design standards. It’s as if none of this applies to Norwich."
However, the county council says the scheme was approved before those design standards were put in place and it was not possible to provide full segregation at that location.
The council said an independent safety audit had not raised issues with the shared use.
Martin Wilby, chair of the Transport for Norwich joint committee, said: “We have worked closely with government and all stakeholders throughout the development of this project to deliver a scheme which achieves the maximum benefit for all users at what is one of the busiest highway junctions in the county.
"The works carried out will generate significant journey time savings on the city’s most popular bus route to the UEA and hospital, whilst providing an environment where more people choose to walk and cycle, where it is easy to cross the road and where there is less congestion."
Traffic modelling estimated the changes would cut bus journey times by two minutes in the morning peak and by up to seven in the evening.
Paul Martin, commercial manager at First Bus Eastern Counties, said: “Although Grapes Hill roundabout has only been fully opened for less than a week, bus passengers using our services are already experiencing the benefits.
"The long queues of traffic that used to form exiting Chapelfield North, especially at peak times, are not there, as it is now far easier for vehicles, including buses, to get out onto the roundabout.
"Early indications are that this scheme has more than delivered the journey time savings that were predicted, which is vital for our long term aim to encourage people to use more sustainable modes, like public transport."
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