Reclaiming the roads for cyclists
Their wheels have been spinning along the urban sidewalks of the USA and the boulevards of Europe and now an underground cycling movement which takes its name from a sociodynamic term is becoming increasingly active in Belfast.
The first Critical Mass cycling rally was in San Francisco in 1992 with the idea of asserting the right of cyclists to use the road.
Since then it has spread around the world with groups springing up and falling away. There have been two Critical Mass groups in Belfast, but the use of social media has been keeping this one running.
Since September last year there have been rides in Belfast city centre on the last Friday of every month. Up to one hundred cyclists take part in the excursions around the city organised on Facebook.
The rides start at the Albert Clock and last about an hour during which participants spread across the lanes and form their own stream of traffic.
The movement itself has been the cause of some controversy among cycling bloggers and in America has led to instances of conflict with the authorities, never mind irate motorists caught in a tailback.
In Belfast, the group has not met any noteable problems, in spite of a unique situation in Northern Ireland which has trapped the unwary in the past.
While the issue of how to deal with contentious loyalist parades is being examined, groups not affiliated with loyalist marching orders have been caught up in the current legislation controlling them.
A circus parade in Bangor was halted because it had not notified the Parades Commission and vintage vehicle rallies also have to notify the body of their intended routes.
For groups like Critical Mass, which do not have a formal structure, such requirements appear unworkable and they do not apply for permission.
A spokesperson for the group explained their thinking: "We take the view that cars in traffic don't need permission to be there so we shouldn't.
"There are concerns that the new public order laws going through the assembly could make the whole thing an illegal gathering if more than 50 people take part without 37 days prior notification."
However, he said that the local rides had a mix of participants from cyclists holding militant views on road access, to parents and children just having a scoot about the city centre.
To lighten the mood one of the cycles sports a music system. The next ride on Friday calls for participants to sport fancy dress.
The term critical mass itself refers to a momentum in society which becomes self-sustaining and fuels further growth and there are those who want to see more cycling in Belfast.
Andrew McMurray of Friends of the Earth is one of them. He is part of the Belfast Cycle City initiative which wants 10% of all journeys in the city to be made by bicycle within the next decade.
"I would say that there is great potential in Belfast which is not really being capitalised on," he said.
"There has been a rise in cycling over the last decade judging by the sales from retailers and the statistics from traffic monitoring."
He has helped organise a conference in the city on Monday to encourage the Department of Regional Development to make the city more bike friendly.
Mr McMurray said cyclists in Belfast seemed to fall into two types, lycra-wearing men under the age of 40 commuting to work and a small number of women using bikes fitted with shopping baskets on retail forays. It is a demographic he would like to see widen.
"Using the road network doesn't really appeal to families cycling, because of the fear factor and traffic flow.
"What we would like to see is a dedicated cycle path network which will encourage people by making it safer to be on the road."