Motivated by the ubiquity of control-affine systems in optimal control
theory, we investigate the geometry of point-affine control systems with metric
structures in dimensions two and three. We compute local isometric invariants
for point-affine distributions of constant type with metric structures for
systems with 2 states and 1 control and systems with 3 states and 1 control,
and use Pontryagin's maximum principle to find geodesic trajectories for
homogeneous examples. Even in these low dimensions, the behavior of these
systems is surprisingly rich and varied