Portsmouth City Council's ruling Lib Dem cabinet decided the on-road route – from Henderson Road in Eastney to South Parade Pier – is the safest option for walkers, cyclists and motorists.
It means that diagonal parking will be replaced with paral
lel parking, leaving 150 fewer spaces.
City leaders say the spaces are rarely used except on busy days when cars will be able to park on Southsea Common instead, as reported in The News.
But seafront traders have hit out at the decision.
Simon Reed, manager of Mozzarella Joe's, said on behalf of all traders: 'If we want to attract more visitors we need more car-parking spaces, not less.
'Overflow car parking on the Common 17 days a year is woefully inadequate.
'And a large number of visitors support the small takeaway concessions during the winter months with a coffee in their cars enjoying the view the head-on parking allows.'
The move comes after more than a decade of debate about whether cyclists should be allowed to cycle on the promenade.
Earlier this year council leader Gerald Vernon-Jackson overruled the idea, saying it is not safe, despite an opinion poll in favour of the plans.
Since then officers have been working on the new route.
They say the two-way cycle lane on the road, which will be separated from traffic by a small kerb, is the safest option.
Cyclists have welcomed the scheme, which will cost around £138,000.
Jon Spencer, the Portsmouth spokesman for national cycling group CTC, told The News: 'This will be a vast improvement to the route currently used by Portsmouth's many cyclists, and will encourage more people to cycle in Southsea.'
Work is set to get underway in March next year, at the same time as planned resurfacing works by council road contractor Colas.
Council leader Gerald Vernon-Jackson said that once the route was in place the council would clamp down on people who were illegally cycling on the promenade.
He added: 'This will provide a safe place for people to walk, on the promenade; a safe place for people to cycle, on a designated cycle lane; and a safe place for people to be able to drive.'
The second phase of the route, from South Parade Pier to Clarence Pier, is set to be completed in 2011.
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