The evolution of the Critical Mass
The Critical Mass (CM) is a worldwide popular form of activism in which cyclists try to draw attention to themselves and their problems as road users. The CM organizes itself via Facebook & Co and rides as a crowd through the city. The action is legal because, from a legal point of view, more than 15 bicycles constitute a closed group of vehicles, which means, among other things, that the CM is allowed to ride on the streets and is not required to use the bike lanes. The actions are clearly focused on the fun of cycling - the bikes are sometimes decorated and cargo bikes with music systems provide a nice setting.
I took some data on the development of CM in Germany and especially in Hamburg from the recommended sites and analyzed it a bit:
Participants in May 2014
The turnout figures are usually published by people close to the CM while the police, as is often the case with protests, releases lower figures in some cases. Maybe not all values are correct, but the order of magnitude and regional distribution should fit.
Hamburg is undisputedly the German center of the CM - in May, the traditionally strong crowd here cracked the 5000 mark.
But why is that the case? One possible interpretation would be that cyclists have a particularly hard time here. This would explain the rather low number of participants in the cycling city of Münster.
Spotlight on Hamburg
There is a ride archive for the Hamburg CM, which also includes the number of participants. I have enriched and analyzed the dataset with some data about the weather on the respective days.
The number of participants is increasing!
The May record was preceded by a clear trend. Of course, the number of participants fluctuates depending on the time of year but already the CMs in March and April were significantly above the previous year's values. Last year's maximum of 3252 bikes in August was almost reached in April in 2014.
... but depends on the weather
Although the people of Hamburg are used to quite a bit of weather, rain and temperatures naturally have an influence on the turnout figures: In the graph, the trend towards more participants at higher temperatures can be seen well.
Nevertheless, the CM often had several hundred participants even at sub-zero temperatures - a hardened nucleus that doesn't seem to mind the cold much. Precipitation has a stronger influence: At the two CMs on clearly rainy days, the number of participants dropped to less than 200 people.
What's next?
The Hamburg CM might be so successful because it has an event character and also includes people who are not bike activists. It remains to be seen how long the trend towards more participants will continue. Personally, I think that it is already a success for Hamburg's cycling if the number is permanently above 2000 riders.