The campaigners want restrictions imposed on the Canongate section of the Royal Mile to make it easier and more pleasant to walk between Waverley Station and Holyrood.
Options in a report published today include making the street pedestrian only, closing it to all but buses and essential vehicles, and slowing traffic by changing the road’s appearance to make it seem narrower.
Living Streets Scotland director Stuart Hay said: “We have shown one of Scotland’s most historic and important streets is substandard and a national embarrassment in terms of the experience it provides for pedestrians.
"Most similar iconic streets in world heritage areas will have been pedestrianised decades ago.
"Scotland and its capital continue to lag behind whilst European cities like Oslo, Paris and Brussels making even more areas car-free.
"More ambitious plans are needed to make the section of Edinburgh’s historic Royal Mile near the Scottish Parliament much more dedicated space for walkers, which means restricting car access.
"Whilst we understand calls to retain some access for vehicle including buses, we believe this compromised option is unlikely to free up enough space for people to enjoy the street and move around safely.
"Car-free days have shown what can be achieved when the street isn’t a busy transport corridor, but work on more permanent change is needed.”
“There should be a clear vision to end the neglect of the lower Royal Mile and make it one of the best historic streets to visit in Europe.”
Mr Hay said the state of Canongate spelled out in the Miles Better report was indicative of the problems faced by pedestrians across Scotland.
It highlighted obstacles such as narrow pavements, bollards, poor crossings and busy junctions, which could be particularly challenging for people with mobility aids, guide dogs or pushchairs.
South Scotland Labour MSP Claudia Beamish, co-convenor of the Scottish Parliament’s cross-party group on cycling, walking and buses, for whom the report was compiled, said: “Its important findings ring true with my own experience of this commute.
“It makes a terrible impression for visitors to the Scottish Parliament to encounter poor accessibility and dangerous traffic.”
Edinburgh Cty Council transport and environment vice convener Karen Doran said: “We have a range of ambitious, long-term strategies to overhaul streets in the city centre to create a more accessible, inclusive environment.”
She said the council’s Edinburgh City Centre Transformation strategy included proposals to “see much of the Royal Mile closed to traffic, and bus and local access only on Canongate.”
Ms Doran there were also plans to improve all pedestrian access points to Waverley Station, while crossing points had been reviewed across the city to see where dropped kerbs were needed.
She said: “We take the needs of those with mobility problems extremely seriously and engage closely with the Edinburgh Access Panel on new projects and policies, while our city-wide A-board ban has been welcomed by equalities groups for reducing street clutter.
"We’re now working with Living Streets to identify non-essential street furniture for removal.”