Title: Laetitia DABLANC et Konstantinos CHATZIS
Author: Antoine Picon
Last saved by: Prénom Nom
Company: Ecole Nationale des Ponts et Chaussées

The Involvement of State and Private Engineering Consulting firms in Travel Demand Modeling in France, 1960-2005

Konstantinos CHATZIS and Gilles CRAGUE

Laboratoire Techniques, Territoires et Sociétés (CNRS-ENPC-UMLV)
Ecole nationale des ponts et chaussées
6-8 avenue Blaise Pascal – Cité Descartes
77 455 Marne-la-Vallée cedex 2 – FRANCE

chatzis@enpc.fr / crague@enpc.fr

Abstract 
This paper deals with the ‘four-step’ urban travel demand model, used to forecast traffic in urban networks. Four-step modeling is central to the transportation profession, yet its history is not particularly well recorded. This paper aims at beginning to fill in that large gap by offering a first long-term analysis – from the 1960s to the present time – of the trajectory of this kind of modeling approach in France. It shows how the roles of the main actors – the (central) state and private engineering consulting firms – have radically changed in the course of the last decades. The role of the French state has changed from the main actor in the 1960s to a “standardizer” in the beginnings of 1970s, while private (and often non French) firms became, from the middle of 1980s on, more and more important in carrying out modeling work, based on an international commercial software.

1. Introduction
The technologies used in the transport sector include material technology, such as vehicles or types of infrastructure, as well as technologies of the intellect (Goody, 1977 and Latour, 1987), i.e., the knowledge and know-how produced and used by the professionals working in the sector, frequently embodied in mathematical tools. This paper deals with one such technology of the intellect : the ‘four-step’ urban travel demand model (see insert), used to forecast traffic in urban transport networks and subsequently used in the infrastructure investment decision-making process. Four-step modeling is central to the transportation profession, yet its history is not particularly well recorded. This paper aims at beginning to fill in that large gap by offering a first long-term analysis – from the 1960s to the present time – of the trajectory of this kind of modeling approach in France. 

In doing so, we will focus on the different actors involved in four-step modeling, as well as the “means of production” and the “raw materials” that are necessary for its production and implementation. Indeed, modeling requires a wide range of actors – individuals and institutions (research bodies and training institutions, private engineering consulting firms, government departments, etc.) – occupying different places within the “production process” (carrying out research, development or maintenance work, etc.). It also requires ‘raw materials’ (e.g., data from surveys on household mobility) as well as ‘means of production’ (i.e., computer facilities and software). 

Our paper consists of two parts. We will begin by describing the role played by the French State in ‘four-step’ modeling in France from the 1960s up to the present. This influence began to dwindle in the 1980s when urban travel demand modeling in France underwent major changes in terms of the mathematical structure of the models themselves and the IT environment – changes driven, in particular by foreign private engineering consulting firms. We shall deal with this development in the second section of the paper. 

Unless specific references are given, information provided comes from our own personal field research (interviews with actors, archives of institutions involved in modeling…).

General principles of ‘four-step’ urban travel demand modeling

This type of modeling seeks to forecast the flows within an urban traffic network in a given urban agglomeration. Modeling the traffic is based on a combination of four steps. The four steps are as follows:

Trip generation: process of modeling the trips generated to and from the zones making up the urban area studied for the period under review. This brings the socio-economic characteristics of the area into play.

Trip distribution (or destination choice or zonal interchange analysis) : process of modeling the distribution of trips generated to and from a given zone and between other zones in the urban area in accordance with the attributes of transport systems. This phase makes it possible to determine the trips corresponding to various possible origin-destination pairings.

Mode split (or mode choice or modal split): the demand for trips measured in the previous phase is broken down between the various available modes of transport (mainly private cars and public transport). This phase analyzes options such as price, the current and future public transport offering, motorization rate, etc.

Trip assignment (or route or traffic assignment): Breaking down demand over the transport network studied.

NOTA BENE : We should stress that the ‘four-step’ model is not a model, but a general modeling approach (this is why we prefer to refer to ‘four-step’ modeling). Indeed, several different models were produced within each of the four steps. 

2. Modeling and the French State, 1960-2005 : from the state as ‘innovator’ to the state as ‘standardizer’

The French State, via the Ministry for Infrastructure and its various technical agencies, was a key actor in introducing and developing ‘four-step’ travel demand modeling in the 1960s and the early 1970s. However, this initial dynamism did not last and the State’s role changed. The French State ceased to be the key actor in developing new travel demand modeling techniques. It became instead a ‘selection’ operator and an agent of ‘standardization’ of existing modeling practices. Indeed, in the mid-1970s the Ministry for Infrastructure chose a small number of models which were subsequently standardized. These standardized models were disseminated and implemented throughout the national territory via the local agencies of the Ministry for Infrastructure. From the mid-1970s on, there were few original developments concerning demand modeling at French State level. 

2.1. 1960-1973/74 : Innovation and proliferation of models under state guidance
In 1953, only 20% of French households had at least one car. This percentage only increased to 30% in 1960. However, during this decade the trend accelerated: 40% of households had a car in 1964 and 50% by 1967. In 1973 the figure had risen to 62%, while 9% of households already owned two cars. Staying in 1973, trips made in private cars amounted to 330 billion traveler-kilometers, not including the distances traveled by foreign cars, i.e., four times more than the number of kilometers covered by public transport (Braudel and Labrousse, 1993). This explosion in the number of privately-owned cars called for an infrastructure that would need to be designed according to new rules. Thus, French urban travel demand modeling was born right here in the 1960s. 

However, the first event of significance in the history of French modeling took place in the US. During the 1950s and the beginning of the 1960s, several French engineers working for the State, mostly belonging to the corps des ponts et chaussées (bridge and road building corps) (Chatzis and Ribeill, 2005), were sent by their employer – first the Ministry for public works, which subsequently became the Ministry for infrastructure following the merger of the ministries for public works and construction in 1966 – to the US to study the various different techniques used by American engineers to forecast urban travel demand (Dupuy, 1975). These people were to be especially prominent in the development of transport planning techniques (including urban travel demand modeling).

Joseph Elkouby (X-ponts 1944) was one of the first to make the trip in 1952-53. He was followed by other (generally young) fellow members of the corps des ponts et chaussées: Serge Godberg (X-ponts 1948), Marc Halpern-Herla (X-ponts 1949), Claude Abraham (X-ponts 1951), Christian Gérondeau (X-ponts 1957), Jean-Daniel Ichbiah (X-ponts 1960) and Mikhaël Sakarovitch (X-ponts 1957) to name but a few. Let us recall that the most prestigious route to becoming a member of the corps des ponts et chaussées is via two elite institutions: Ecole polytechnique (which is also referred to as ‘X’), which dispenses general scientific training, and Ecole des ponts et chaussées, specialized in civil engineering. Thence the denomination ‘X-ponts’ to denote members of the corps des ponts et chaussées.

As well as organizing these trips to the US, the French State also set up a number of organizations at this time tasked with urban transport planning and the related modeling techniques. It was the SERC (Traffic survey and research office), set up in 1955 within the Ministry for public works, that played the dominant role in developing French expertise in urban travel demand modeling up to the end of the 1960s when this body made way for two structures intended to be complementary and based on a ‘division of labor’ between basic research work on transportation issues on the one hand, and surveys and applications on the other. 

Regarding surveys (applications), the SETRA (roads and highways technical survey bureau), set up in 1968, and included an urban section tasked with urban transport planning and the related modeling techniques. The SETRA, a Paris-based structure within the Ministry for Infrastructure was supported by several local agencies known as CETE  (Infrastructure technical survey bureaus). We should note the importance from the outset of the Ile-de-France (Greater Paris region) due in particular to its enormous public transport network. Transport modeling in the Ile-de-France was not the responsibility of a body affiliated to the SETRA as was the case in other regions. Instead, travel demand modeling was developed within two organizations. The first of these was the DREIF (Regional infrastructure department for the Ile-de-France), a regional structure under the auspices the Ministry for Infrastructure, which developed its own ‘four-step’ model in the early 1970s. The second organization was the IAURT (City planning institute for the Paris region), which was set up in 1960. At the beginning of the 1960s, thanks to the contributions of Pierre Merlin (graduate of Ecole polytechnique) and Michel Barbier, the IAURP pioneered research into the generalized cost of transport issue– taking account of factors such as monetary cost, time spent, various types of inconvenience, etc. – which were subsequently used to study the split between transport modes, privately-owned cars and public transport (i.e., the third step in ‘four-step’ modeling) (Merlin, 1984).

There were seven different CETEs : CETE Méditerranée (Aix en Provence, 1968), CETE Nord (located in Lille), set up in 1970, CETE de Lyon (Lyon, 1971), CETE Sud Ouest (Bordeaux, 1971), CETE Normandie (Rouen, 1971), CETE de l’Ouest (Nantes, 1972), CETE de l’Est (Metz, 1973).

Regarding basic research into transportation issues (including modeling), the IRT (Transport research institute) dates from 1970. Finally, in terms of providing training, in the mid-1960s Ecole nationale des ponts et chaussées (ENPC) (Chatzis, 1998) began teaching travel demand modeling techniques to future engineers. 

Although the Ministry for public works and its successor, the Ministry for infrastructure, played a key role in ‘acclimatizing’ and developing models for forecasting urban traffic, other actors were also actively involved in urban travel demand modeling in the 1960s. These included a number of public and private engineering consulting firms, frequently worked on behalf of public authorities.(including the Ministry for Infrastructure). We should mention in particular: the private engineering consulting firm known as SEMA (Economics and applied mathematics bureau), set up in 1958; the private engineering consulting firm known as SETEC (technical and economic survey office) created in 1957; the CERAU (Center for urban planning survey and research), a public consulting firm attached to the Caisse des Dépôts et Consignations (Deposits and Consignments Office). Lastly SEMALY, a semi-public company located in the Lyon region, which was set up in 1968, was responsible for a classic model, named TERESE, which has been used extensively since it was first developed in 1974 to design public transport infrastructures (such as subways, protected bus lanes, etc.) 

This wide range of actors gave rise to a wide range of models for each step in ‘four-step’ travel demand modeling approach, apart from the third step (mode choice) which generated little research outside of that carried out by the IAURT. Several types of models were developed simultaneously and it appears that certain French contributions of the period bore fruit at a later stage but only outside France (Bonnel, 2004). Hundreds of reports and memoranda covering both the different models and the (household mobility and traffic) surveys necessary for making such models operational were produced by the actors that we have just referred to. 

When glossing through the various reports and memoranda of the period, we encounter several operational models (run on computers) for the different steps of travel demand modeling. For the period 1965-1974, we should mention the following: ATTRAVAR (trip distribution step, CETE Normandie) ; CAPRE (trip assignment step, IBM France) ; EVAREAU (trip assignment step, developed by the team headed by M. Sakarovitch at IRT) ; FABER (trip generation-distribution steps, SETRA) ; AFSIM (trip assignment step, SETRA) ; DAVIS (trip assignment, developed by Barbier de Saint-Hilaire (X-ponts 1962), SETRA and IRT) ; SATURNE (trip assignment step, IBM France) ; AFTAT (CETE Sud Ouest) ; ATCODE and ADECODE (SEMA) ; BIREG (CEREAU) ; ATLANTE (trip generation-distribution-mode split steps, SETRA) ; OPPORTUNITY MODEL (trip distribution step, SETRA) ; URBA model (trip distribution step, CETE de l’Ouest, Ecole nationale supérieure de mécanique,) ; TERESE (assignment step, SEMALY, CETE de Lyon, IMAG (Institut d’Informatique et Mathématiques appliquées de Grenoble, a Grenoble-based Research Center on Applied mathematics)).

2.2. From 1975 to the present: The State as ‘standardizer’
This burgeoning activity was brought to a halt at the beginning of the next decade. In the early 1970s, the French Administration chose among the modeling practices of the 1960s a limited number of models. The models were ‘standardized’ by the Ministry for Infrastructure, or more specifically, its technical arm, the SETRA. Thus, between 1971 and 1973, several circulars relating to transport infrastructure surveys were issued, accompanied by numerous documents and guidelines published by the SETRA. We can also find articles summarizing ‘doctrine’ relating to urban travel demand modeling, particularly those that appeared in Revue Générale des Routes et des Aérodromes (review of highways, roads and aerodromes), a periodic publication widely read by public works engineers. 

These ‘standardized’ models were disseminated and implemented throughout the national territory thanks to local public agencies of the Ministry for Infrastructure (especially the CETE). In the mid-1970s, the same public agencies provided also private professional planners with these standard models (Koenig, 1974). The impacts of this period are still in evidence today insofar as up-to-date versions of some models developed in the early 1970s – such as DAVIS, an assignment model for privately cars, developed by the ponts et chaussées engineer F. Barbier Saint Hilaire within the IRT, and TERESE, an assignment model for public transport (cf. supra) – are still widely used. 

From the 1980s on, only few original developments concerning travel demand modeling emanated from the various public agencies. Existing models were adapted for use on PCs without major functional extensions except for toll-based infrastructures. How can we explain the small presence of the French State and its various departments in the modeling landscape after 1980? One can look at the standardization of modeling practices by the State, which appears to be a double-edged sword. While well drafted standards may ensure good results (on average) by providing a framework for and guiding local practices, they do so at a cost of making operational practices much more rigid and the organizations employing such standards far less receptive to innovation (Douglas, 1986). Another reason that may cast some light on the feeble presence of the French state in the modeling landscape after 1980 concerns the increasing transformation of French State engineers from technicians into managers. As regards managers, ‘the more you move around, the more managerial experience you acquire’. Such mobility is especially prized in the higher echelons of the French public sector. However, the production of expertise requires a certain stability over time and this condition was not met in the case of ‘four-step’ modeling. Indeed, most of the engineers of the ponts et chaussées involved in urban travel demand modeling in the 1960s, subsequently abandoned their careers as modelers.

For example, CETE Méditerranée in collaboration with ALMA, a Grenoble-based firm, developed a PC version of TERESE. DAVIS was adapted for use on new machines between 1983-1985 by its creator, Barbier de Saint Hilaire himself in collaboration with IMAG. DAVIS’ creator subsequently adapted it to run on ATARI and on PCs from 1990. However, the major innovation in the assignment model itself came in 1993 (20 years after DAVIS had first been created) with the incorporation of toll-based infrastructures.

We should note that although there was little innovation from government departments regarding modeling itself, the French state remained highly active in carrying out (and updating) household mobility surveys. 

Regarding more theoretical research, we note that once the standardization of models had been completed, important theoretical developments were taking place concerning the question of mobility (thanks in part to the results of surveys launched within the scope of modeling activities), accompanied by increasing criticism of the modeling techniques that had been practiced up to this point. Such criticism included the following: the models were too conservative and simply extrapolated trends already observed in the past; the models (and the modelers) tended to favor the car ; critics challenged the sequential basis of models (no feed-back was provided for between the different steps of modeling process); the aggregate nature of the modeling practiced (the unit was the territorial ‘zone’) : for critics, the use of ‘typical’ (average) behavior tended to mask the great divergence in the attitudes of households or individuals regarding mobility; the lack of a theoretical basis at ‘micro’ level for individual behavior (Merlin, 1984 and Le Nir, 1991). Even though such criticism was common in France and other developed countries, it only generated alternative urban travel demand modeling techniques outside France (see below).

3. 1980-2005, French modeling ‘subject’ to external influences: the role of foreign engineering consulting firms

The 1970s and 1980s witnessed important developments in modeling practices concerning both the mathematical formalism of the modeling techniques and the computer technology (both hardware and software). As regards software, modeling entered the era of global (international) commercial software. In terms of formalism, the period was characterized by two opposite but ultimately complementary trends (complementary because they concerned different application issues): a trend towards more complex modeling practices – reflected in the so-called disaggregate  approach which reached France in the 1980s – contrasted with a move towards simpler more straightforward models, called strategic models, that were only taken up in France in the 1990s. While the French State had been the force behind the introduction and development in France of urban travel demand modeling in the previous period (in the 1960s and the early 1970s), the main vectors of change from the 1980s on were the (predominantly non-French) private engineering consulting firms. The current ‘four-step’ modeling landscape in France is a reflection of these various developments.

3.1. The disaggregate approach in France
The disaggregate approach was developed in the US/UK from the 1970s on and gave pride of place to the mode choice step. This type of modeling reached France in the mid-1980s just when the mono-modal approach, which had been the dominant approach since then, used mostly for sizing and assessing (road) infrastructure from a socio-economic perspective, was faced with new challenges. Developments reflected in the new Plans de Déplacements Urbains (Urban Transport Plans) as well as a concerted will to favor other modes of transport over the car gave rise to new modeling needs (for example, the 1996 French law on the air officially challenged the longstanding predominance of motorized transport). This helped rekindle interest in France in the mode choice step and its most recent operational tool, the disaggregate approach to modeling. 

Disaggregate modeling attempts to describe the behavior of an individual in the course of his/her trip planning by translating behavior into the probability of choosing a given mode of transport in accordance with his/her inherent characteristics and choice ‘environment’. These probabilities are then applied to a class of individuals and aggregated.

The mono-modal approach consists in using separate modeling techniques for each mode of transport to be studied.

Disaggregate modeling was introduced into France at the beginning of the 1980s via two parallel channels. The first of these was research: a number of researchers carried out academic research into disaggregate modeling techniques (Raux, 1983 ;  Hivert, 1985 ; Bouyaux, 1988 ; Chevrolet 1986). The second involved a series of practical applications developed by sector professionals and mainly by a number of foreign engineering consulting firms. The RATP (body responsible for the Parisian metro and bus network) had recourse to the services of Cambridge Systematics Europe – the European subsidiary of the major US engineering consulting firm, Cambridge Systematics – to develop a disaggregate model focusing on the mode choice step (IMPACT model). The second French disaggregate modeling experience involved the city of Grenoble. It was headed by a working group consisting of public actors such as CETE de Lyon and Grenoble city planning agency (for the data gathering phase), IMAG and ALMA (responsible for implementing the model), and Cambridge Systematics Europe which was in charge of developing the model. The model was initially used to evaluate the impact on mode choice of different policies tested (increases in petrol prices, reimbursement of public transport commuting costs, doubling of parking costs). The results obtained during this initial work encouraged the team from Grenoble to use this same model for designing the city’s tramway line. The Grenoble experience was later ‘transferred’ to Nantes. To finish our introduction to disaggregate modeling in France in the 1980s, we should mention a study carried out between January and September 1987 at the main French Transport Research Institute, INRETS (formerly the IRT), to forecast traffic on the future ORLYVAL link to Orly Airport. This project also involved a UK private engineering consulting firm, MVA Consultancy (CETE de Lyon at al., 1986 ; CETUR, 1985; Hivert et al., 1988). 

Cambridge Systematics Europe became the Hague Consulting Group in 1985 which in turn became RAND Europe in 2001.

In the 1990s, other French bodies availed of the services of foreign engineering consulting firms (some of which opened French branches in the 1990s) in order to use disaggregate modeling techniques. The RATP currently uses version 3 of IMPACT (mode and destination choice model), developed by MVA Consultancy. STIF (Transport authority for the Greater Paris area) has also used the services of the Hague Consulting Group to develop ANTONIN, composed of a series of disaggregate models (Bhouri, 2002 ; THEMA et al., 1991). 

3.2. The strategic model in France
Like disaggregate models before them, strategic models were first developed outside France in the 1980s (in Birmingham, London and Edinburgh), before reaching France in the 1990s (Masson 1998). In geographical terms, strategic models adopt a ‘simpler’ approach to travel demand questions – for a given area, the number of zones under consideration may be divided by ten in relation to traditional ‘four-step’ modeling – however, at the same time, the strategic model takes account of more socio-economic variables and a larger area, thus giving a regional perspective to trips generated from and taking place within an urban area. Strategic models are not intended to replace traditional models but may be used to quickly test the numerous scenarios envisaged and greatly reduce the number of options that will then be tested by traditional ‘four-step’ models. The key actor in strategic modeling in France is SEMALY (cf. supra), which became a private engineering consulting firm in 1992 and developed a strategic model (known as MOSTRA) for Lyon, with the help of a research institute, Laboratoire d’Economie des Transports (LET). In 1995, a prototype was developed, followed by a working model in 1996 which was adapted for the cities of Grenoble and Bordeaux in 1997-1998. The most recent version of the model was adapted for Bordeaux with the development of the third generation of MOSTRA. 

3.3. Global (international) commercial software arrives in France
Alongside disaggregate and strategic modeling, which, as we have seen, was in France’s case a mainly imported phenomenon, the 1990s also witnessed the arrival in France of a number of multi-modal software planning tools (accommodating both privately-owned cars and public transport forecasting) that are currently used by both public actors and private engineering consulting firms. 

EMME/2 was one of the first examples of (international) commercial planning software to arrive in France. (the cost of a license varies between €15,000 and €105,000 (1999 prices)). In France, EMME/2 is used by CETE Méditerranée and CETE Sud-Ouest, the DDE du Nord, and by several territorial authorities such as Lille, Montpellier and Bordeaux. 

TRIPS is another imported software package widely used in France (€13,500 to €33,200), developed in the UK by MVA Consultancy in the 1970s. TRIPS is used by the local authorities of Saint-Etienne, Nice Strasbourg and Mulhouse. The current (aggregate) ‘four-step’ model used by the DREIF (MODUS) was first developed in 1997 based on TRIPS software. 

Other non-French software in use in France includes MIN UTP, developed in the US by Cambridge Systematics Systems and distributed in France by HCG (€12,200 euros). ANTONIN, the disaggregated model of the STIF, uses TP+/VIPER software – the successor of MIN UTP – as a toolbox in order to edit and visualize networks and to carry out matrix-based calculations. 

The case of the German engineering consulting firm PTV needs a special mention. In the 1990s, with the advent of multi-modality, Barbier de Saint Hilaire, the creator of DAVIS (see above), entered into an arrangement with the German firm to incorporate certain features of DAVIS (tolling and congestion) within the (‘four-step’) modeling chain of their VISEM/VISUM program, which had been developed from 1987 on. This had the advantage of being a multimodal model that was already available on the international market. Furthermore, VISEM/VISUM included effective generation-distribution models as well as a disaggregated mode choice model. The newly-created software, known as VISEM/DAVISUM (which cost between €6,400 and €57,900 in 1999), offered a complete (multimodal) chain model. It was a big success in France: four CETEs currently use DAVISUM while the program has also been taken up by the SNCF (French State railways) and the IAURIF (formerly the IAURT). However, DAVIS continues to exist alongside DAVISUM: the former was developed and distributed by Barbier de Saint-Hilaire, the latter by PTV (Bhouri, 2002 and GESMAD, 2003). 

VISEM module: trip generation, trip distribution and mode choice steps; VISUM : assignment step.

The advent of desktop computing and planning software that we have referred to has triggered radical changes in the make up of modeling teams: the importance of computer scientists, in charge of translating the model into a programming language has diminished in favor of  modelers.

3.4. The current French ‘four-step’ modeling landscape 
The current French ‘four-step’ modeling landscape is the direct result of all of the aforementioned developments. The key feature is the importance of private engineering consulting firms, which are frequently part of major French service and equipment groups. They have highly specialized modeling skills (suited to the French environment) however they mainly use standard software, developed within an international framework and lack any real innovative capacity (at least from an international perspective) (Débizet, 2004).

A small number of local and regional authorities (Ile-de-France, Lille, Grenoble, etc.) have technical modeling facilities. The various CETEs, which still own the rights to the models for several French cities, maintain a presence in the modeling landscape although their role is related more to their history than their present-day dynamism. Research in the field of urban modeling (research institutes such as INRETS, universities and the CNRS) appears to be characterized by insufficient staff levels and fragmentation, though some kind of renewal has been observed since the mid-1990s (Baye et al., 2002).

Shortcomings in the area of research are compounded by other factors such as the fact that  French modelers mainly receive their training ‘on the job’. Few academic training courses currently exist in France. Apart from a small number of modeling classes on offer at Ecole des  ponts et chaussées, we should mention the modeling course provided as part of the postgraduate degree in urban and regional transport (Université Lyon II and Ecole nationale des travaux publics  de l’Etat, a Lyon-based engineering school) which makes this the lone academic standard bearer of urban travel demand modeling. Alongside these university courses, occasional training is provided to sector professionals by Ponts-formation, which is affiliated to Ecole nationale des ponts et chaussées. 

In symbolic terms, the ‘withdrawal’ of public bodies, whose expertise has largely been transferred to private engineering consulting firms, is apparent in the fact that the Ministry for Infrastructure which used to commission state engineers to draft reference manuals relating to urban travel demand modeling now uses engineering consulting firms to prepare these documents. 

4. Conclusion
Our paper is a first attempt to analyze the history of the ‘four-step’ model in France from 1960 up to the present time. In doing so, we focused on the different actors involved in four-step modeling in France, as well on the ‘means of production’ and the ‘raw materials’ that were involved in its production and implementation. It is shown how the roles of the main actors – the (central) state and private engineering consulting firms – have radically changed in the course of the last decades. The role of the French state has changed from the main actor in the 1960s to a “standardizer” in the beginnings of 1970s, while private (often non French) firms became, from the middle of 1980s on, more and more important in carrying out modeling work, based on an international commercial software.

References

Baye, E., Blancher, P., Chi, A. and Lichère, V. (2002) ‘Bilan de compétences des laboratoires de recherche français en matière de modélisation des déplacements de voyageurs et de marchandises’. Research report, Ministry for Environment (ADEME). 

Bhouri, N. (2002) ‘Intermodalité : Bilan et perspectives des systèmes informatiques’, Research Report INRETS. 

Bonnel, P. (2004) Prévoir la demande de transport, Presses de l’ENPC, Paris.

Bouyaux, P. (1988) ‘Modélisation désagrégée des transports urbains : une application à la ville de Rennes’, Revue d’Economie Régionale et Urbaine, 5, pp. 783-809.

Braudel, F. and Labrousse, E. (1993) Histoire économique et sociale de la France, t. IV, vol. 3 : ‘1950-1980’, PUF, Paris. 

CETE de Lyon, CETE de l’Ouest, CETUR, MELATT (1986)  ‘Modèles désagrégés, principes généraux, méthodologie, applications (Grenoble, Nantes).  

CETUR (1985) ‘Les déplacements domicile-travail et domicile-école, modèles désagrégés de choix modal, application au cas de l’agglomération grenobloise’. 

Chatzis, K. (1998) ‘Die älteste Bauingenieurschule der Welt – die Ecole des ponts et chaussées, 1747-1997’, Bautechnik Spezial, pp. 26-42. 

Chatzis, K. and Ribeill, G. (2005) ‘L’espace des carrières des ingénieurs de l’Equipement dans le public et le privé (1800-2000)’, Revue française d’administration publique, 116, pp. 651-70.

Chevrolet, D. (1986) ‘Modèles désagrégés de déplacement dans l’agglomération grenobloise’. Unpublished Ph.D dissertation, University of Grenoble. 

Douglas, M. (1986) How Institutions Think ?, Syracuse University Press, Syracuse (NY).

Débizet, G. (2004) ‘Déplacements urbains de personnes : de la planification des transports à la gestion durable de la mobilité. Mutations d’une expertise’, unpublished Ph.D dissertation, University of Paris I. 

Dupuy, G. (1975) Une technique de planification au service de l’automobile, les modèles de trafic urbain, Copedith, Paris.

GESMAD (2003) ‘Pratiques de la modélisation dans les collectivités locales françaises’, Research Report for the Ministry for Infrastructure (DRAST). 

Goody, J. (1977) The domestication of the savage mind,  Cambridge University Press, Cambridge. 

Hivert, L. (1985)  ‘Modélisation de la demande de transport : présentation critique de l’outil désagrégé’, unpublished Master thesis, University of Pierre et Marie Curie-Paris VI.

Hivert, L., Orfeuil, J.P. and Troulay, P. (1988) ‘Modèles désagrégés de choix modal : réflexions méthodologiques autour d’une prévision de trafic’, Research Report INRETS n° 67.

Koenig, G. (1974) ‘Génération, distribution, affectation de trafic sur les voies nouvelles’, Revue générale des routes et des aérodromes, recyclage 1974/Formation permanente, Fascicule n° 1, pp. 1-16. 

Latour, B. (1987) Science in action. How to follow scientists and engineers through society, Harvard University Press, Cambridge (Mass).

Le Nir, M. (1991) ‘Les modèles de prévision de déplacements urbains’, unpublished Ph.D dissertation, University of Lumière Lyon 2. 

Masson, S. (1998)  ‘Interactions entre système de transport et système de localisation : de l’héritage des modèles traditionnels à l’apport des modèles interactifs de transport et d’occupation des sols’, Les Cahiers Scientifiques du Transport, 33, pp. 79-108. 

Merlin, P.  (1984) La planification des transports urbains, enjeux et méthodes Masson, Paris.

Raux, C.  (1983) ‘Modèles de prévision des comportements de mobilité quotidienne’, unpublished Ph.D dissertation, University of Lyon II and Ecole nationale des travaux publics de l’Etat. 

THEMA, CORE, HCG-France (1999), ‘QUATUOR. Outils dynamiques de simulation pour la gestion des déplacements dans la région parisienne’, Research Report for the Minsitry for Insfrastructure (DRAST), Part 1.