The First World Road Congress took place in 1908 on the initiative of the French Minister of Public Works, to deal with road problems such as the inadequacy of macadam pavement for the new motorized vehicles’ weight and speed. It was also an answer to a movement led by European actors, like touring and automobile clubs, regarding cross-border travelling and the standardization of danger signs.

The Permanent International Association of Road Congresses (PIARC) was created in Paris in the following year as a forum for the discussion of these new road issues and divided into two sections: construction and maintenance, use and traffic regulation. Although it had a dominant European presence in terms of delegates and reporters, the PIARC became a global platform of production and circulation of knowledge of road techniques. This was particularly relevant in the congresses held in the first three decades (Paris, 1908; Brussels, 1910; London, 1913; Seville, 1923; Milan, 1926; Washington, 1930; Munich, 1934; The Hague, 1938). The creation of PIARC technical committees (1938) enhanced its role. The proliferation of these committees after World War Two was also a response to the competition by the International Road Federation, created in 1948, in the USA. The congresses’ proceedings and the technical committees’ publications show the evolution of the experts’ concerns, both with regard to technical problems like the study of sub-soil, pavement, the mechanization and control of works, and road planning. Other issues like financing, the regulation of traffic, road signs, or urbanism were also discussed. PIARC’s Latin motto "Via Vita," meaning “road is life,” asserted its optimistic stance on the role of roads in development and prosperity. The congresses normally had a technical programme, a road material exhibition, and field trips, as well as a social programme. Generally organised by a local National Road Bureau, these were often used rhetorically by the political regime of the hosting country to claim technical superiority (as it happened with the showing-off of ‘automobile-only roads’ in congresses during the interwar period). National Road Bureaus were created in the 1920s in several European countries, inspired by the English Road Board, as a way to promote a more scientific approach to road renewal works. Thirteen PIARC National Committees were also created in parallel by the end of the 1930s. Portugal would only do so in 1951.

The Ninth World Road Congress, the first after the Second World War, was held in Lisbon, from 24 to 29 September 1951, the same year as the reappearance of  the PIARC’s bulletin. As with the congress in Seville, the choice of Lisbon was again that of a country which in the preceding World War had allegedly remained neutral. Discussions focused on technical issues. The organisers of the Lisbon Congress aspired to universality and to harmony between countries based on an assumed technical neutrality, a goal materialized symbolically by a sculpture placed in the lobby of the congress’s exhibition: a globe, with a metal ribbon curled in a helix (suggesting a road) with the flags of all participating countries. The Lisbon Congress was presided and organised by the Portuguese Independent Roads Board (JAE - Junta Autónoma de Estradas). Six questions were put to the two statutory sections: 1 and 2) Progress made since the Hague Congress in 1938 regarding road and runway pavements and their materials, and regarding the study of roads’ sub-soils; 3) Basic factors in road design and studies of traffic; 4) Economic justification of road-works; 5) Construction and maintenance of roads in general and of urban roads in particular; 6) Construction, maintenance, and allocation of funds for roads in thinly-populated or underdeveloped countries. General reporters had to synthesize the 64 national reports presented on these questions. They were Portuguese engineers, who were civil servants placed in key positions in Portuguese technical institutions, respectively: the director of JAE Road Construction Services; the director of the Civil Engineering Laboratory; a professor at the Faculty of Engineering in Oporto; the director of the Central Department of the Traffic Services Directorate; the director-general of Urbanization Services (and former JAE engineer); the chief engineer of the Public Works Department of the Colonial Office. The Congress numbered around 1200 delegates, of whom approximately 200 were official delegates from national governments, 200 from public bodies, 330 from other collective members, the rest being individual members. The great absence from this Congress was the USA, with no official governmental delegate.

The Lisbon Congress was also a way to emphasize a representation of Portugal that legitimised, politically, the Portuguese right-wing dictatorship Estado Novo (New State) and also technically at international and national levels, the Portuguese highway engineers. Politically, the congress was hosted by Estado Novo at the highest level: the opening and the closing sessions were held at the National Assembly and the congress had the high patronage of the President of the Portuguese Republic and four of its Ministers were Honorary Presidents of the Committee of Honour (Ministers of Public Works, Foreign Affairs, Colonies, and Communications). Speeches underlined the combination of traditional and modern values, promoted the political regime, its imperial character, and its technical competences. Technically, it was very much about showcasing the JAE’s achievements. Portuguese engineering had been represented in all World Road Congresses, and particularly by the JAE’s directors of road construction and maintenance services since its creation (1927). The secretary-general of the Lisbon Congress was the JAE director of road maintenance services who had been responsible for designing the most important road policy documents issued in Portugal in the 1940s (namely the national road plan and the national road statutes as they stood in 1945), which he presented in an article published in PIARC’s Bulletin of 1951 as an achievement of Portuguese highway engineering’s modernity. The congress’s technical sessions were held in the Higher Technical Institute, one of the most important Portuguese engineering schools. There, a documentary exhibition on roads was set up, giving special relevance to the work done by the JAE on Portuguese roads in its 24 years of existence. At a national level, the Lisbon Congress also worked to celebrate the JAE: for instance, the elitist Automobile Club of Portugal, whose president was a member of the Congress’s Committee of Honour, dedicated an issue of its journal to the Lisbon Congress, stating that it was the recognition of the JAE and its technicians’ eminently ‘national and patriotic’ work.

The congress’s logo epitomised the JAE’s national and international affirmation. Its aspiration to combine modernity and tradition is symbolised by a diamond-shape highway node and the five quinas (escutcheons), which were an ancient symbol of the Portuguese nation, present in her flag. Through this representation of a node—an intersection of roads created to avoid traffic jams , very rare in Portugal at the time­­—the logo also shows the aspiration to an image of modernity of Portuguese highway engineering, far removed from reality

Portraying both the ideologies of techno-nationalism and of techno-internationalism, the congress reflected a part of a transnational history of technology in which European actors played a major role.