History of N-340
The N-340 is essentially Roman in origin. Many parts of the route formed the Via Heraclea of the 2nd Century BC. This was upgraded and renamed the Via Augusta in 4 AD. The Via Augusta had a major junction with the Via Domitia (the first Roman road built in Gaul, to link Italy and Hispania).
The road's Roman origin, and part of its exact original location, are today testified by the Arc de Berà, a Roman arch in Tarragona which now sits on an N-340 roundabout. The route also appears in ancient sources such as the itinerary from Cadiz to Rome inscribed on the Vacarello Cups and the Itinerario de Antonino Augusto Caracalla. It is interesting to note that these 'itineraries' don't mention the roads by name, but consist of a list of towns enroute and the number of Roman miles between them.The Via Augusta ran down the coast to present day Valencia and then inland to Villanueva de la Fuente (Ciudad Real) before winding down through the river Guadalquivir valley via present day Alcala, Cordoba and Seville to Cadiz.
There is Roman road that follows the coast of Andalucia. This is often referred to as Via Augusta as well. It may well have been upgraded around the same time or it might be a modern misnoma. This second 'Via Augusta' is recorded as branching off at Valencia and reaching Guadix, returing to the coat at Almeria. Others refer to a branch at Lorca the joins the coast at Vera. Both then follow a coastal route all the way to Cadiz. Interestingly, this is similar exact route of the N-340, since both the Via Augusta and N-340 coast road followed a partial inland route through present day Murcia.
The Malaca (Malaga) to Gadez (Cadiz) route was called the Via Aurelia, and according to an itinerary of Emperor Antonino. "ITER A MALACA-GADI: SIVEL (Fuengirola) , CILNIANAM (San Pedro), BARBARIANAM (Manilva), CALPE-CARTEIM (San Roque). Numerous straight sections of rmodern road, such as the Golden Mile in Marbella, and close proximity to Roman sites such as Puente Romano arch bridge and Rio Verde Villa, also suggest that section of the N-340 have Roman origins.
However there is little direct proof; certainly nothing as substantial as the preserved section of the Via Domitia that can be seen in Narbonne, France. It is likely that the Via Aurelia took a route about 1.500m further inland to avoid numerous large bridges over the Rivers Guadalmansa (flumen Salduba) Rio Verde, Rio Guadaiza, Rio Guadalmina. If so the Puente Romano over the Aroyo Nagüeles was most likely a spur road, perhaps conecting the Rio Verde Villa and various small Garum factories on the coast.
As is widely known, after the Romans left Hispania the roads fell into disrepair, and there is little record of subsequent improvement by the Visigoths, Moors or Catholics. As late as the 18th century, travel along the coast was by ship rather than road. Port records up to this point demonstratethe substantial import and export of goods by ship between adjacent towns such as Marbella and Estepona. One major disadvantage of the early coastal road was that it crossed numerous rivers which had to be traversed by ferry, adding to the time and cost of journeys.
In 1759, during the reign of Ferdinand VI, the role of 'peones camineros' was created; these were the workers charged with highway maintenance. Each peón caminero was responsible for one league (5.5km) of road. In 1852, Isabel II ordered the design and construction of the official casillas (little houses) for the roadmen.
In 1864, engineer Pablo Alzola constructed nine 15m span elliptical arch stone bridges over the Rio Verde, Rio Benanolar, Rio Guadaliza, Rio Guadalmina, Rio Velelerin, Rio Castor and Rio Padron in Marbella and Estepona. These original stone arches can still be seen clearly today underneath the modern spans.
The post Spanish Civil War 'Plan Peña' of 1941 concerned road improvements and a new system of road numbering; this was when the N-340 coast road gained its number.
Since the beginning of the millennium, the N-340 has gradually been replaced by the Autovía A-7 and Autopista AP-7, thus becoming a series of isolated sections of 'old road'. Many sections have been ceremoniously handed over by the Ministry of Formento to local town halls. Nonetheless, most of the route can still be followed.The N-340 has its own historical-cultural website at www.n-340.org, and it has been blogged about many times.