A new bike path with trees built into it risks becoming a defining image of “inept design”, say cyclists.
The track in Norwich, which is still under construction, includes cobblestones and tree pits which narrow the space for cyclists to less than 45cm (18ins) at points.
The design was condemned as “beyond belief” and “totally unfit for purpose” by the Norwich Cycling Campaign.
Transport for Norwich insisted the path was well designed but not yet finished.
The path on Prince of Wales Road is part of the fourth phase of a £2.6m upgrade programme, mainly funded through central government.
Contractors for Transport for Norwich, a partnership between Norwich City Council and Norfolk County Council, are halfway through eight weeks of work to build the new cycle lane, widen paths, upgrade crossings and resurface side roads.
Richard Bearman of Norwich Cycling Campaign said the path was necessary to link the train station and city centre, but was not “remotely acceptable”.
“This is in a very high profile place and has the potential to become a defining meme for inept design,” said Mr Bearman.
“Spending thousands of pounds of public money on unusable facilities will make the city council and our fine city a national laughing stock.”
A Transport for Norwich spokesman said the design standards demanded sensitivity to existing surroundings.
“Comments are being passed on a scheme which is still under construction,” he said.
“The trees are at the edge of an extended pavement which will be levelled off providing a much wider area for cycling and the designs which were consulted on widely have passed all necessary safety checks.”
The spokesman also pointed out the route was “uphill and in a busy city centre location so is not designed to be used at speed”.