  A model consisting of a mixture of superconducting and quantum links is
proposed to describe the integer quantum Hall transition. The quantum links
correspond to tunneling of electrons between trajectories trapped in adjacent
potential valleys, while the superconducting links correspond to merging of
these trajectories once the Fermi energy crosses the saddle point energy
separating the two valleys. The quantum Hall transition in this model
corresponds to percolation of the superconducting links. Numerical calculations
and scaling analysis using two different approaches yield the critical exponent
$\nu \approx 2.4$ and a two-peak conductance distribution at the critical
point. The role of quantum coherence is discussed, and an explanation of
experimental observations claiming different universality class for the quantum
Hall transition is suggested. The model suggests that the critical behavior of
the superconductor-insulator transition from the insulating side is in the same
universality class as the quantum Hall transition.
