The Roman Empire was undoubtedly of the greatest empires; they were able to aggregate outside technologies to create their own technologies unique to Rome. However, not all of Rome's practical inventions were from other nations and countries. Many were were devised within Rome's own ingenuity. Also what lead to Rome's greatness was its ability to conquer and lead.
The Romans developed many architectural structures which were so practical that they are still used today. The Romans developed aqueducts, bridges, tiled roofing, arches, roads, and etc. All of these inventions aided Rome's growth of civilization and made easier the everyday lives of the Roman people. However, of the most practical of Roman inventions were the Roman roads.
The Roman roads enabled communications to be swifter, as the Roman Empire was very large with many provinces to command. The Roman roads also eased the strain of travel for soldiers and merchants. The Roman was in fact very large, and the Roman roads connected the major cities to the outskirts and villages which weren't nearby main civilization.
What made the Roman roads distinct in particular was the quality of build and straightness. It was the Roman legions who built the roads. A tool called the groma was used to ensure straightness of path. Although the roads were renown for their straightness, natural abstacles were avoided and built around.
Codrington, Thomas D. Roman Roads in Britain. Society for Promoting of Christian Knowledge; Macmillan, 1919.
Chevallier, Raymond. Roman Roads. University of California Press, 1976.