Abstract: A land vehicle comprises first and second wheel motors that control respective rates of rotation of left and right rear wheels. An accelerator adjustment assembly controls the first and second wheel motors and comprises first and second linkage assemblies that cause the rate of rotation of an inside rear wheel to slow during a turn exceeding a predetermined turning radius. In preferred embodiments, the land vehicle is a sweeper machine comprising a debris collection assembly, a hopper, and a hydraulic cylinder adapted to lift and lower the debris collection assembly. The debris collection assembly comprises a collection body, a brush adjustment assembly, and a rotary brush assembly. The brush adjustment assembly comprises a height adjustment lever and an actuator comprising a piston rod. The piston rod is adapted to raise and lower a first end of the height adjustment lever such that the rotary brush assembly is raised and lowered.