Why salt roads?

Already in the early years of the Roman Republic, with the growth of the city of Rome, roads were built to make transportation of salt to the capital city easier. An example was the Via Salaria (originally a Sabine trail), leading from Rome to the Adriatic Sea. The Adriatic Sea, having a high salinity due to its shallow depth, had more productive solar ponds if compared with those of the Tyrrhenian Sea, much closer to Rome.