The 马 mǎ (horse) was an integral component to China's military might throughout the Imperial Dynasties. During the Western Zhou Dynasty military might was measured by the number of war chariots available to a kingdom. And, horse-drawn chariots and carts were essential for communication, control and the transportation of supplies and military units.
In fact, China is credited with the invention of the stirrup and the breast-strap harnessing system, both major advancements in horse-driven transportation. And, was known to develop superior horse-drawn vehicles long before their western counterparts.
Despite the horse's importance to Chinese history the horse-drawn carriage would not see wide-spread use among any social group except china's wealthy and elite. This is due, in part, to the fact that domestic horse-breeding rarely succeeded in China. This meant that the quantity and quantity of horses was dependent on either expensive trade with their nomadic neighbors, international trade programs of the Han Dynasty, or the imperial breeding programs and mandates of the Tang Dynasty. The necessity to acquire quality horses was one of the reason that the Silk Road was established.