Final answer:
Having the same road system improved China's empire by enhancing communication and administrative efficiency, facilitating trade and economic development, and contributing to the unity and expansion of domestic markets. The Grand Canal and other infrastructures were vital for economic dominance and the distribution of technological innovations.
Step-by-step explanation:
Having a uniform road system throughout China would have improved the empire in several significant ways. One key aspect is the enhancement of communication and administrative efficiency. With standardized roads, carts, and bridges, such as the substantial Qin-era bridges over the Wei river, the rulers were able to dispatch messengers, move armies rapidly, and exert greater control over their vast territories. Moreover, the existence of specialized lanes for different users, notably a central lane reserved solely for the emperor, symbolized power and reinforced societal order.
The road and canal systems, including the Grand Canal, also facilitated trade and economic development. These infrastructures made it possible to efficiently move goods, like southern rice to the north which helped to feed large armies, and contributed to the prosperity of regions like Sichuan. This network played a critical role in the empire's ability to hold together and expand economically. The improvement in intra-empire connectivity allowed for greater unity and facilitated the expansion of domestic markets.
The Sui Dynasty's construction of more roads and the Grand Canal further linked the Yellow and Yangtze Rivers, advancing the unification of China. This vast network continued to be intrinsic to China's economic vitality, contributing to the empire's dominance in iron, copper, and porcelain production, and the dissemination of the Four Great Inventions.