A London Assembly report recommended reducing speed limits
A charity has called for a 20mph speed limit across all residential roads in London to encourage a greater sense of safety and community.
Research from Living Streets found nearly 14% of children played out on their street five times a week.
That compares with 44% of their parents aged 30-40 who did.
The charity will later host an "old-fashioned" street party near east London's Brick Lane to show "what our streets should be used for".
It said London's streets were in danger of losing the social function they had in the past, as they shifted from being social hubs for the community into spaces considered no-go areas for children.
"The number of neighbours we know has declined, local shops have closed and it is becoming increasingly rare to see children playing out on the streets," said the charity's chief executive Tony Armstrong.
"We have effectively designed ourselves out of our own communities through urban planning that has failed to prioritise people."
Earlier this year, a London Assembly report recommended reducing speed limits on hundreds of London roads to 20mph.
The measure would lower road accidents and carbon monoxide emissions, it said.