Hot-electron transport in GaAs/AlGaAs quantum wires and quantum wells having various lateral confinements are investigated systematically using the Lei-Ting balance equation theory. Intrasubband and intersubband transitions of up to 21 electron subbands in quantum wires and seven subbands in quantum wells due to acoustic phonons, optic phonons and impurities are taken into account. Linear and non-linear electron mobilities are presented as functions of carrier density, electron field (or drift velocity), temperature and lateral confinement for these one-dimensional (1D) and two-dimensional (2D) systems, and compared with those in bulk material. At low temperatures, the electron mobility in quantum wires can be much higher than that in quantum wells or in bulk material in optimum conditions. However at high temperatures, when optic phonon scattering dominates the other scattering mechanisms, the mobility in quantum wires can hardly exceed the value in quantum wells or in bulk material.