Pontoon bridge a pontoon bridge to cross the Bosphorus and Emperor Caligula built a bridge at Baiae in 37 AD. For Emperor Darius I The Great of Persia (522–485 BC), the Greek Mandrocles of Samos once engineered a pontoon bridge that stretched across the Bosporus, linking Asia to Europe, so that Darius could pursue the fleeing Scythians as well as move his army into position in the Balkans to overwhelm Macedon. Other spectacular pontoon bridges were Xerxes' Pontoon Bridges across the Hellespont by Xerxes I in 480 BC to transport his huge army into Europe: According to John Hale's "Lords of the
Cable barrier several types of highway barrier did not find an appreciable difference in fatal and severe injuries between cable barrier and W-beam barrier. Both were significantly more hazardous than concrete barrier, however were less hazardous than having no barrier at all. There are two types of cable barrier systems in use today, low-tension and high-tension. Each system has its advantages and disadvantages, but in general, a high-tension system has a higher initial cost with lower long-term maintenance costs and concerns. During the expansion of cable barrier use throughout the 1980s and 1990s, the low-tension system was specified almost exclusively. This system