驭 originally pictured a hand (又) on a horse (马), driving a chariot. It's the literary/classical form of 御 and survives mainly in compounds like 驾驭 (to drive/control) and 统驭 (to govern).
马 is the horse radical and gives 驭 its literal image, a hand reaching for the horse to drive it. The verb extends to 'control, command, manage' anything (驾驭, 驭手). Simplified 马 keeps its three-stroke compact form.
又 is the old hand-with-two-fingers pictograph. Beside the horse it shows the driver's hand grasping the reins, a compound-ideograph (会意) structure, not phono-semantic. No sound contribution; the meaning comes from horse + hand.
