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In page Roman roads:

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Roman construction took a directional straightness. Many long sections are ruler-straight, but it should not be thought that all of them were. Some links in the network were as long as 55 miles (89 km). Gradients of 10%–12% are known in ordinary terrain, 15%–20% in mountainous country.[citation needed] The Roman emphasis on constructing straight roads often resulted in steep slopes relatively impractical for most commercial traffic; over the years the Romans realized this and built longer but more manageable alternatives to existing roads.[citation needed] Roman roads generally went straight up and down hills, rather than in a serpentine pattern of switchbacks.[citation needed]