The history of transport is largely one of technological innovation. Advances in technology have allowed people to travel farther, explore more territory, and expand their influence over larger and larger areas. Even in ancient times, new tools such as foot coverings, skis, and snowshoes lengthened the distances that could be traveled. As new inventions and discoveries were applied to transport problems, travel time decreased while the ability to move more and larger loads increased. Innovation continues as transport researchers are working to find new ways to reduce costs and increase transport efficiency. International trade was the driving motivator behind advancements in global transportation in the Pre Modern world. "...there was a single global world economy with a worldwide division of labor and multilateral trade from 1500 onward." The sale and transportation of textiles, silver and gold, spices, slaves, and luxury goods throughout Afro-Eurasia and later the New World would see an evolution in overland and sea trade routes and travel. Land Road The first earth tracks were created by humans carrying goods and often followed trails. Tracks would be naturally created at points of high traffic density. As animals were domesticated, horses, oxen and donkeys became an element in track-creation. With the growth of trade, tracks were often flattened or widened to accommodate animal traffic (hollow way or drover's road). Later, the travois, a frame used to drag loads, was developed. Animal-drawn wheeled vehicles were probably developed in the ancient Near East in the 4th or 5th millennium BC and spread to Europe and India in the 4th millennium BC and China in about 1200 BC. The Romans had a significant need for good roads to extend and maintain their empire and developed Roman roads. In the Industrial Revolution, John Loudon McAdam (1756–1836) designed the first modern highways, using inexpensive paving material of soil and stone aggregate (macadam), and the embanked roads a few feet higher than the surrounding terrain to cause water to drain away from the surface. With the development of motor transport, starting in 1886 in Germany and in the U.S. in 1908 with the production of Ford's first Model T, there was an increased need for hard-topped roads to reduce washaways, bogging and dust on both urban and rural roads, originally using cobblestones and wooden paving in major western cities and in the early 20th century tar-bound macadam (tarmac) and concrete paving. In 1902, Nottingham's Radcliffe