Two modifications of the intervening opportunities model, accounting f
or the 'long lines effect' are proposed. The first modification deals
with the instant reaction of customers at long queues and incorporates
the statistical dependence of their behaviour. In the second model cu
stomer behaviour is determined by past data, which make their behaviou
r statistically independent. The concept of self-consistent distributi
on is introduced, its existence is investigated, and properties of sel
f-consistent distributions are described.