FME. Can only speak of a time in the seventies in Europe (where they originated)
where Criteriums were big in Flanders and Netherlands area (or neighboring borders)
Within a travel radius on any day of the week you could travel to a criterium race.
Around a local town area/ville usually around a couple of blocks, was the circuit.
Held in the format of a points-race. First, second, and third rider at every 3rd to 5th lap
gets 3, 2, 1 points respectively (with double points at final endsprint)
Sprint laps depended on the size of the circuit and the total number of laps.
Events often had prizes (called primes, pronounced "preems", and were usually cash)
for winning specific intermediate laps (for instance, every 10th lap).
A bell is usually rung to announce to the riders that whomever wins the next lap, wins the prime.
Primes, were collected from local businesses and local support clubs (individual riders had clubs)
Officials favoured locals, and Locals turned out in mass to support their favourites.
Local Support Clubs even paid start monies, so "their" favourite would start in that local event.
Carnival atmosphere, with frites & Beer stalls on the circuit.
Great day out, with many "Stars" turning up, "out of the blue" to watch or compete.
No pre-nomination entry was required.
Quite different from your standard Road Race.
Cheers

Lone Rider- I rode on the long, dark road... before I danced under the lights.