The cellular view of a street carnival
A moving crowd. Encounters are constant and brief, because nobody occupies the same metre twice.
The conditions of this room
Four numbers decide what a crowd does: how tightly it is packed, how loud it is, how fast alcohol arrives, and how much attention is available for the people beside you. Everything below is either a published figure or derived from one.
What those conditions do to people
A street carnival is a crowd with a current running through it. Density sits around 1.6 people per square metre — high but not crushing — and roughly a third of everyone present is moving through rather than standing, which is the defining property of the format.
That churn is why the encounter rate lands mid-table at 12.1 per person per hour despite reasonable density, a workable 97 centimetre speech range and alcohol in circulation. The people around you are constantly being replaced, so contact is frequent, novel and short.
It shows in what survives: 423 lasting ties, the lowest of any drinking venue modelled. Carnival maximises the number of different people you brush past and minimises the chance any one of them is still there ten minutes later.
What the model produces
Measured output from a standard run: 1,200 people, 4 hours of venue time, fixed seed, no parameter overrides. Every room on this site is run under identical conditions, so these figures are a like-for-like comparison rather than a set of individually flattering runs.
The crowd is a simulation and is presented as one. What is not invented are its constants: walking speed against density, the proxemic zones, the collapse of speech range with noise, the Widmark blood-alcohol curve and the conversational group limit all come from published work, cited above and listed in full in the engine.
Real places like this
Every gathering below is modelled as this kind of room. Attendance figures are published numbers for the period stated.
Questions
How many people attend Rio Carnival?
Around 5 million street revellers per day according to Riotur, making it among the largest recurring street gatherings in the world.
Why do carnival encounters not last?
Roughly a third of the crowd is in transit at any moment, so the people around any given person are continually replaced. Contact is frequent but rarely lasts long enough to become anything.
How big is Notting Hill Carnival?
Around 2 million people across two days, making it one of the largest street festivals in Europe.
How this is modelled
Each person is one cell with a position, a body mass, a Widmark distribution ratio, an openness trait and a reserve of energy. They walk at the speed the local density allows, drink at the rate the room serves, and when two of them stay within speech range long enough, a bond forms. Most bonds are nothing.
What separates an encounter that creates something from one that does not is whether it bridges two groups that were not previously connected. A tie inside an existing group mostly restates what that group already knows; a tie across a gap carries information neither side had. That distinction is Granovetter's, and it is the mechanic the whole model turns on.
One parameter has no citation and should be read as an assumption: attention, the share of a person available to whoever is beside them rather than to a stage, a road or a rite. It is the variable that separates a street crossing from a dancefloor at similar density, and it is the one this model asserts rather than borrows.