The Project of Urbanization of the new Avenue Juan Carlos I on the buried railroad in the city of Cadiz (Spain), nowadays in construction was designed in July, 2001 by the Technical Office of Projects and Investments of the Area of Urbanism of Cadiz City Council, as continuation of Railroad Project of the ferrous routes, written by the Department of Promotion and initiated in July, 1999.

The existing urban structure in the city of Cadiz and the resultant one of the model of city proposed by the P.G.O.U (1995) were obliged references to the Special Plans of the Walk of the Railway and of the Station written in July, 1999, especially the role of the road and the railway itself, which is the part of the structural analysis of the existing city that affects more directly in the planning.

To sum up the most relevant aspects that characterize the city are the following:

• Road Structure very atypical
• Shortage of the first level structural roads
• Deficient mesh of the transverse roads

About the description of the Cadiz network of roads, it stands out as fundamental characteristic the fact that between the extreme South of the city and the historical enclosure located to the North, only two axes appear with clear continuity: the Avenue, backbone of the city, and the complex industrial highway; the first one canalizing the traffic of light vehicles and with an absolutely clear trace, and the second one canalizing the heavy traffic of the port for a more confused trace, with strict sections and crossing residential and commercial zones of great density.

The functioning analysis of the network of roads concludes that the longitudinal permeability in the existing city presents basically deficiencies of lack of continuity in many of the longitudinal routes of the mentioned mesh, also deficiencies of scanty capacity in the routes that possess continuity and lack of clarity and strong environmental impact, especially at the industrial highway.

The Bay of Cadiz thinks in a geographical strategic position, which has provoked human settlement from the antiquity. The physical way, of high ecological value, is characterized by the presence of natural and transformed marshes, which awards islander's character to some of the cities.

In this territory, a polynuclear system of cities ends up by being formed, with metropolitan relations of interdependence, agglutinated by the own Bay that defines it, articulated by the highway N-IV, and integrated by the municipalities of Cadiz, San Fernando, Puerto Real, Puerto de Santa Maria and Chiclana de la Frontera. The set generates a population nucleus near to 400.000 inhabitants, the third one for the total size of Andalusia, being constituted in sub regional centre.

Cadiz is the head-board of the system with strong reasons to be so. Today and after a resplendent past marked by a flourishing maritime trade and a powerful naval industry, the city bases its bad economy on the services that generates its condition of administrative cardinal centre, and on a minimized industrial sector in crisis, supported on the naval construction and the commercial port.

After jumping the walls of its dense, populous and most valuable Old town, the modern city is formed in a development period by means of strongly speculative processes and successive landfills of the Bay. Stopped today the above mentioned processes, the city - silting and without new soils – expels population of middle and high classes, while it suffers the consequences of that period supporting a brutal density, shortage of free spaces, and a deficient accessibility by virtue of a network of roads disjointed and overwhelmed for the car pressure, and a scanty utilization of the alternative means of transport.

The railway of the Bay passes in parallel with the CN-IV. The service relies on long route lines, regional and surroundings. The above mentioned, in spite of being relatively enough used, do not take advantage of the whole potential of the tracing, due to the disability of its route and the shortage of alighting-places.

In the city of Cadiz, the railway channel crosses longitudinally the whole city for its backbone, reaching the Station in touch with the Old town and the port. It offers a great potential as axis of collective transport. Nevertheless, the tracing in surface and the high traffic, produces an environmental negative impact and there preventing the continuity of the roads and pedestrian streets. All this has provoked that the city develops of backs to the railroad therefore making its margins appear as degraded spaces.

The railroad and its roads, which so much reached to the development of the city of Cadiz, turned at the end of the 20th Century into an obstacle for the connection of three big nucleus of population of the city: Intramuros and both zones of Outside, to one and another side of the route of the train. Every nucleus, with similar levels of population, between 45 and 50 thousand inhabitants’ lack of connections except for the runways, and one or two underpasses only for vehicles.

The involution of the railway service and the suppression of the disadvantages that generates its tracing, turn into fundamental aim of the transport’s politics and of environmental improvement into the City of Cadiz and into the Metropolitan Area of the Bay. This fact places the project of "Integration of the Railway into the city of Cadiz" (1999) inside a series of performances that could make possible to modify the mentioned economic situation, stimulating, as consequence the spatial reordering of the urban and industrial zone, including a series of structural hanging performances, allowing a major integration of the neighbourhoods and a major fluency in the communications of the city.

The execution of this work is a strategic need for the city, since it allows to solve many problems that stem from a bad structure of the access roads to the historical centre of Cadiz with the negative effects that it has in the port, commercial and industrial activity and for the losses of time that supposes coming to the points of destiny of the city.

Good parts of the problems of the street connections of the city were due to the presence of the railway route. Nevertheless, with the perfectly rectilinear tracing, the railway plays in Cadiz a role structurally similar to that of the Avenue. To reduce the effect of the railway barrier both in the functioning of the transport and in the urban is a prior aim of the Project of Urban Integration of the railway. This will stand for good both sides of roads after the Integration, improving the longitudinal scheme of streets, in the same way that raises the increase of the transverse fret of the routes, to allow the mesh of the railway roads.

The performance to lead to end not only had to subscribe to the area of the improvement of the infrastructures, but it had to suppose the definitive unions of three zones of population, separated also socially and economically, serving as impulse to recover its hegemony and importance as capital city.

The barrier, besides physical and psychological that supposed the routes of the train, stopped heaped in a part of the neighbourhoods that other epochs condemned to the underdevelopment and that they are presented as a space degraded in terms of urban landscape.

To bury the routes and to liberate the space as new axis of the city was marked as the principal aim of the project, since it was understood as one of the big problems of the city the fact that this one were divided in two zones as a result of the route of the train, which was acting as a barrier inside the city provoking the break in the urban structure, preventing the integration of the slums of one and another side of the railroad and contributing to the social segregation of the city, at the time that it was disturbing the functioning of the network of roads and the transport of vehicles, since it was not allowing the longitudinal continuity of the roads and was interrupted by the transverse ones preventing the mesh of the network of roads.

According to this analysis, included already in the General Plan of Arrangement (1995), the aims marked by the project of urbanization of the liberated soil were:

• To improve the accessibility of the city
• To improve the joint between neighbourhoods
• To improve the urban image
• To increase the transverse permeability

The project of integration of the railway and treatment of the liberated spaces, it was stimulated by the Cadiz City Council and financed by this one in 20 %, besides with the contributions of the Department of Promotion 60 % and Junta de Andalucia 20 %. It is the City Council the one that proposes the division of the works, saving itself the performance to the surface treatment of the liberated spaces, for understanding that it is a labour more precisely and perfectionist inside the urban area.

The result of the urban integration of the railway in Cadiz foresees in the shape of economic reactivation and distribution of the opportunities of development thanks to the principal aim of the Project: the resolution of the internal mobility the city; still when close to the project of integration they propose three complementary lines of performance: the improvement of the collective transport, the creation of alternative routes to the Avenue and the eventual construction of the third access to the city.

To this strategy directed to the improvement of the mobility in the Bay, there add others focused specifically to solving structural problems or of functionality of the urban road, between that the performances stand out for its importance on the longitudinal road and the transverse mesh of the network of road.

The construction of the new Avenue Juan Carlos I on the integration of the railroad will be the first performance that extends and improves notably the connections of the longitudinal roads of the city with the current accesses to Cadiz. It supposes, besides a direct access to the Port across, a route of sufficient section, allowing to unfold the traffic of weighed, at the time that plays an important role as distribution of streams of traffic in the scene of construction of the third access to the city, articulating the correct transverse mesh of the current axes and making possible the correct diffusion of the traffic in the rest of the urban area.

Given its central position in the outside, the new avenue will allow a reorganization of the itineraries of the urban buses and to the being coincidental itinerary with that of the railway, and the intermediate stations coincide with intersections between the principal transverse road and the longitudinal one, the interchange can be solved of effective form between urban buses and suburban rail network, increasing the attraction of the collective transport and helping to reduce the load of traffic in the network road, acting as a real " urban underground ":

The new Avenue Juan Carlos I, the great articulator of the changes of mobility who generates the integration of the railway, search in its set the alteration of the mesh of the road, solving the existing problems of longitudinally connection and cross street of the roads, as well as a functional improvement of the system of accesses in the relations with the Bay.

Its location in relation with the city allows developing its function as a great axis articulator of the mobility in the city, allowing the reduction of traffic on both only principal current routes and avoiding the appearance of new traffic on the rest, which there will be able to reinforce the capacities of leisure and walk. The redistribution of the traffic reverberates not only in the functional improvement of the network of roads, but also in the notable Increase that it will suppose from the environmental side.