  High-field magnetotransport experiments provide an excellent tool to
investigate the plateau-insulator phase transition in the integral quantum Hall
effect. Here we review recent low-temperature high-field magnetotransport
studies carried out on several InGaAs/InP heterostructures and an InGaAs/GaAs
quantum well. We find that the longitudinal resistivity $\rho_{xx}$ near the
critical filling factor $\nu_{c}$ ~ 0.5 follows the universal scaling law
$\rho_{xx}(\nu, T) \propto exp[-\Delta \nu/(T/T_{0})^{\kappa}]$, where $\Delta
\nu =\nu -\nu_{c}$. The critical exponent $\kappa$ equals $0.56 \pm 0.02$,
which indicates that the plateau-insulator transition falls in a non-Fermi
liquid universality class.
