How to model distribution of arrivals in chunks I want to model a queue system where customers tend to arrive in chunks. The queue represents vehicle arriving at a traffic light (consider just a single approach) and they tend to arrive in chunks because of green/red phases of upstream traffic lights.
What families of probability distributions are best suited for this scenario? Which parameters should I consider?

"Probability Models" by Sheldon Ross gives a great overview of Queueing Theory.
Your question is not well defined: distributions can describe interarrival times, or the number of units passing through a particular receiver over a time. There are too many assumptions to list. You might for instance describe the emission of radioactive isotopes detected by a Geiger counter, which follows very closely independent exponential interarrival times, and Poisson intensity at a single receiver. Generalizations involve multiple receivers, queueing in sequence vs in parallel, and non-independent interarrival times.
