A supporter of a 'healthy neighbourhood' scheme believes "traffic may drop" across the whole area if localised road changes are imposed.
Camden Council is working with Islington Council on plans for a Dartmouth Park Healthy Neighbourhood Scheme in Dartmouth Park.
This will involve closing some streets to through traffic, making some one way and cutting some speed limits, with improvements to pavements, cycle lanes and bus priority lanes.
Opponents warn closing some roads will push traffic, including most lorries, on to others, leading to more congestion and pollution.
More than 2,000 people have now signed a petition to extend the consultation period, which ends this Sunday (August 18) - and will be delivering it to Camden Council tomorrow.
But David Harrison, a member of campaign group London Living Streets, says the area will be "much more pleasant and safer" if the scheme is approved.
He disputed the claim that traffic would rise on some streets, adding: "Islington has installed a large number of LTNs. On only one boundary road has there been a significant increase in traffic, and on several traffic has fallen.
"Quite possibly traffic will drop across the whole area around Dartmouth Park."
Mr Harrison said it was wrong that streets were set up so drivers "dominate", with walking and cycling seeming dangerous.
He said: "It's important to remember that the great majority of households in Camden and Islington do not own or have access to a car."
He said the key question was whether people wanted to keep the status quo, in which a "minority" who drive, and outsider commuters, should continue to dominate, or whether greener, healthier, safer streets were preferable."
The scheme has drawn opposition from Highgate West Hill Residents' Association and conservation group the Highgate Society, who do not believe the data proves it will work. Dartmouth Park Neighbourhood Forum has called for a consultation ending during the summer holidays to be extended.
Mr Harrison still feels the healthy neighbourhood is best. He added: "Do we want a walkable borough where the interests and needs of pedestrians come first, or one where motorists' interests predominate?"
"As an old man, I ask people to think particularly of children. Can we create streets where they can enjoyable walk to school?"
He said the scheme will not stop people making essential journeys although he acknowledged short journeys will take longer, but said it will be much more pleasant and safe for others to walk, cycle or use the "excellent' bus service.
The Highgate Society held a public information afternoon about the scheme on August 3 and will be delivering its petition calling for an extension to the consultation period to Camden Council at 3pm tomorrow (Friday).
Its chair Andrew Sulstan said: "This is a very large LTN and we see no evidence that it is backed by the level of data and analysis to make it a success.
"A lot more work is needed, as there is a grave risk of unintended consequences."
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