Before WW1, motorized vehicles were uncommon and designs were unsuitable for combt. In 1914, British military created the first tanks and included tracks to move over muddy terrrain, machine guns and bulletproof casing. Before put into use, these tanks were demonstrated infront of future British prime ministers- David Lloyd George and Winston Churchill and they were amazed at the machines' ability and called them landships.
Criteria for a succesful tank were minimum speed of 4 miles/hour and ability to climb 5 feet wide.
Speed - 4 miles/hour or 6.5 kphClimb - 5 feet wide or 1.5 m