Deployment path for a " Route Automatisée " project in a French metropolitan transportation context
Renaud Pacalet, Researcher, ENST, 43 rue Barrault, 75013 Paris France, ,
Jean Marc Blosseville, Head of LIVIC/INRETS-LCPC, 13 Route de la Minière, Satory, 78000 Versailles France, tel 33 1 40432900, fax 33 1 40432930, [email protected],
Summary
Deploying automated driving constitutes a problem of high complexity and one of a key subject whose solution decides the realism of a precise project plan. However, it should be solved because the only photography of the final stage could not convince of the whole project feasibility. In order to provide information to the various potential promoters of the "Route Automatisée" Project, it is necessary to know the evolution stages of this system in time, space and the performances. In this paper we will try to explore some possible, probable ways. 4 progressive stages have been identified. The study encompasses identification of the principal stakeholders, determination of their main needs, their expectations and significant characteristics. At the final stage all new infrastructures are dedicated to automated control.
Introduction
The French research group LaRA that stands for " La Route Automatisée " (RA) has been involved for 3 years in the study of automated driving applied to the French transportation context (cf. ref.1). In previous studies carried out in the frame of contracts with the French D.o.T., 4 scenarios were identified (cf. ref. 2-5) :
1. Safety oriented functions for rural roads
2. Automated highways for trucks
3. Suburban automated highways
4. Guided paths in urban areas
Because of the importance of the traffic problems in metropolitan areas, the scenario 3 was approached and studied in depth during 1998 and 1999. A precursor analysis of potential benefits led to a combined evaluation of capacity and safety benefits (reference 5). The present paper deals with a deployment process of automation for this scenario.
The deployment of the Automated Road constitutes a hard problem that should be solved. It is a hard problem because of the number of variables to be taken into account, it should be solved because the only photography of the final stage could not convince of the whole project feasibility. In order to provide information to the various potential promoters of the "Automated Road Project, it is necessary to know the evolution stages of this system in time, space and the performances. In this paper we will try to explore some possible, probable ways.
Stakeholders
In order to analyse the possibilities of deployment, it is necessary to identify the principal stakeholders, to determine their main needs, expectations and significant characteristics. Thanks to this preliminary study, whose conclusions will remain valid whatever the imagined scenario, it is possible to estimate the impact of such or such deployment aspect on the implied actors. The actors to whom our study relates are gathered in 5 distinct categories:
Fundamental needs, essential characteristics of these actors are summarised below.
Public authorities
They do not constitute a single actor but arise as a multiplicity of entities which correspond to segmentations of the management type and administrative responsibilities or to functional divisions. They ensure in particular the double role of defining the overall policy and of managing the infrastructures. With respect to the road network, principal expectations consist in finding the means of ensuring the mobility at the lower cost by reducing adverse effects of road traffic: congestion, accidents, pollution.
With respect to congestion, one seeks territorial answers according to a logic of better use of the available resources and of reduction of the harmful effects of any type. In the urban centres, the projects must be done to the detriment of the car, on the other hand, it becomes imperative to optimise the peripheral expressways.
With respect to the suburban motorways, RA can constitute a solution acceptable for the public authorities : the improvement of the road efficiency and safety constitutes the principal awaited benefit, the improvements of the fuels, engines and propulsion modes constituting the sources to reduce the pressure on the environment.
In addition, RA can help the public authorities insofar as it constitutes an ambitious project likely to contribute to the assertion abroad of national excellence.
However a project carried by the public authorities must have a good total and social acceptability by avoiding constraining regulations and heavy and specific investments. Even carried by the public authorities, the difficulties are to be waited taking into account the long-term character of the project. It must thus profit at the start from a broad consensus from the political community of all political tendencies and from well identified stages, each one revealing benefits.
Public opinion
Principal expectations regard the environmental protection and safety. Transferring part of the travel needs towards non polluting modes (walking, bicycle, roller…), the promotion of the clean vehicles and the development of transit modes can seem desirable improvements regarding the environmental protection. On the contrary, RA can be felt like a threat on the environment.
However, the RA project proposes an evolution of the existing infrastructures by reducing the noise and the consumption of space and they are likely of less opposition than the projects of new road constructions. In addition, the public opinion is sensitive to the problem of road safety that is one of the long term RA objectives. Hence, promoters of RA should clearly point out the ambitious objectives of safety improvements.
Users
The search of a shorter and guaranteed travel time at a reasonable cost constitutes certainly the largest waiting of the users with respect to RA. Expectations regarding safety are quite real but non usable in support of a scenario.
One can distinguish two groups of users. A first group gathers those not very interested by the concept, resistant with respect to a technique which denatures the act of driving by suppressing their liberty of action: those find their interest only in one RA network
offering a real economy in travel time. A second group gathers the drivers for which RA constitutes an opportunity to find time and a freedom lost in the congestion.
The project of RA cannot too quickly advance the argument of safety with respect to the users. Those often consider that the risk often comes from the other drivers. They are thus not ready to invest for equipment intended to protect them from their own errors of control. For the customer safety is due, " it is bought but is not sold ".
A successful deployment also requires to overcome various brakes which regard users : costs of the equipment, the management of the responsibilities, the respect of the private life.
The cost of the equipment is an important criterion which justifies progressive steps, the driving assistance devices can be used as support with RA since the subjacent techniques are very similar. The deployment of the equipment of safety can be accelerated by actions of the public authorities : reduction of the tax pressure, premiums with the acquisition, the possibility of using certain reserved ways (bus lanes).…
The management of the responsibility is important. This point will have to be clarified in a satisfactory way before the users do not have access to partial or total automated control.
Manufacturers and equipment suppliers
They are anxious to preserve the image of the private car associated with the principle of freedom. In this direction, automation to date does not constitute a declared objective. However, pushed by a growing request wishing to delegate the functions of control (at low speed in congestion initially) and eager to propose an image of innovation, they could be done on the contrary, at the proper time, the champion of these systems. It thus appears important to insist that the automobile manufacturers take part in the project (by targeting initially the driving assistance devices e.g.).
The cost of acquisition and the costs of operation of the vehicles constituting an important concern their customers, the manufacturers are naturally attentive with the control and the reduction of the production costs. It is thus necessary to find a way of development
of the systems allowing a fast damping of the efforts of development and research.
Operators and suppliers of services
Because of their reduced implication in the developed principal scenario, expectations and characteristics are not developed here.
Main considerations for a likely deployment path
Finally, this study brings a set of 6 main assumptions to light :
H1 : road users and car manufacturers are stakeholders to be satisfied first;
H2 : the safety of the road transport can progress in a very significant way with the introduction of active safety into the vehicles
H3 : entirely automated control is a crucial stage that maximize benefits. It should be reached as fast as possible;
H4 : any solutions based on an instantaneous evolution of the transport system will lead to failure;
H5 : the road users are more sensitive to arguments of comfort and mobility that to arguments of safety or environmental protection.
H6 : the market segment of the private light vehicle constitutes the best support for the development of RA. To develop as fast as possible this market is considered as an important objective. It is the only market segment whose the size will allow to obtain equipment prices low enough to equip all vehicles in middle term. Any other market segment could just be considered as an introduction market showing technical feasibility.
On the basis of this discussion, a strategy of deployment is proposed. Its goal is to support the fast emergence of the systems of complete automation. Four evolution phases are identified and analysed. They are briefly presented below.
Phase 1 of the deployment : automation at low speed
This phase is characterised by starting up entirely automated driving at a low speed on certain network sections for private light vehicles. This operating mode is intended to improve comfort in the situations of congestion where driving is made particularly tiring. The parts of the network where it is authorised are the suburban motorways and other large axes prone to recurring congestion. On these axes, only certain lanes are opened to the vehicles in automatic mode but these ways are not reserved to them; one will speak about designated lanes; the flow is mixed.
The participation of the infrastructure is minimal. Indeed, the argument of comfort is not enough to justify heavy public investments except, perhaps, on the conceded interurban motorways where the problem of congestion is however considerably less than on the suburban axes. The designated lanes are perhaps equipped with specific markings (particularly neat white lines, magnetic studs or tracks) if this assistance is made essential but it would be preferable by far that it would not be the case. Taking into account the current technological know how, the assumption of a total autonomy of the vehicles does not seem unrealistic.
To equip automatic cars with means of communication should be necessary. It would be thus possible to the managers of the road to authorise or prohibit the use of the automatic mode according to circumstances', even to fix the maximum speed allowed.
The drivers remain in charge of activating or setting off the automatic mode. They start it when it is authorised and stop it as soon as they wish it. When the automatic mode is not possible any more, the driver is alerted and must take again control, or else the vehicle is immobilised. The vehicles in automatic mode are announced to the attention of the other users.
The automatic mode is presented as respectful of the environment. The engine is stopped when the automated vehicle is stationary, which limits the polluting emissions (this argument could however fall from itself if the manufacturers decided to equip all their vehicles with the integrated alternator-starters).
The launching of the automatic mode does not constitute really a technological rupture. The manufacturers develop assistance systems which increasingly use techniques of environment perception. They equip their vehicles with electric steer-wheel, with "automatic intelligent" engine control system, ABS systems, ASR, etc. When the perception and control means become sufficient, complete automation seems a logical continuation, even if the conditions of use are restricted. The fact that several functions share various equipment of the vehicles, induces an economy of scale favourable to cost reduction. The low speed and the choice of particular sections of the network constitute a simplification of the problem. On the other hand, the mixed traffic and the quasi-absence of assistance on behalf of the infrastructure increase the technical difficulty; however the economy of the system does not offer an other choice.
During this phase, several driving assistance systems are developed. They are approved and equip already certain vehicles. Primarily, they are warning functions (monitoring of the state of the driver, warning to the loss of adherence, warning at the dangerous inter-distances, warning at non lawful speeds, detection of obstacles, warning with the accidents downstream, etc). Some of these functions cooperate with the infrastructure whose role is limited however to the transmission of information to the vehicles (speed limits, accidents, works...)
Recapitulation of the phase 1 characteristics
Phase 2 of the deployment: Dedicated lanes and active safety
A sufficient deployment of the equipment developed in phase 1, on a growing number of vehicles will justify the opening of faster and dedicated lanes. The reservation of the lanes guarantees larger safety and effectiveness. It allows a higher speed and thus a reduced travel time for the users. The privilege offered by the dedicated lanes should in addition accelerate the diffusion of the equipment. The entries and exits remain nevertheless free in this phase, i.e. manual.
By opening the existing reserved lanes (exclusive lane or taxi bus) for the automated vehicles or by creating reserved lanes on suitable axes, the public authorities find a solution for the improvement of the infrastructures. New users will be attracted by the travel time reduction, by the reduction of the number of congested situations met by drivers. The important intervention of the public authorities will be justified by the expected benefits in term of safety, environmental protection and increase in the effectiveness of the infrastructures. The reservation of lanes is made possible by the existence of a sufficient number of candidate vehicles.
The approved systems of active safety benefit from the equipment of perception and control already available on the automatic vehicles. The subjacent postulate is the capability of evolution for the vehicles of new generation. One can, without changing model, adding new sensors or to replace existing sensors by others, more powerful, and to increase the processing capability in order to integrate new services. Provided with the function of automation at low speed, a vehicle owner will see himself proposing an active limiting device speed or an anti-collision system like simple extensions of his current configuration.
Some of the safety functions (speed advisors, specification and guiding elements of trajectory, etc.) will ask a co-operation with the infrastructure which will have thus to be equipped with means of communication. It is a delicate point since this implies an important investment in the road network before launching the concerned devices. It requires, as well, an effort of standardisation made in collaboration with the car manufacturers. However the potential benefits in term of safety are important. Moreover, the efforts required to set up these services should be likely partially financed by other services, comfort oriented. The means of communication between infrastructure and vehicles can indeed be also used to transmit commercial or tourist information.
In parallel, the warning systems considered as most effective among those approved during the first phase equip all new vehicles. One will choose of course those for which the experimentation on a small scale did not show perverse effects (this highlights the need for installing structures making possible to observe the effects of such devices) and of which the cost, the effectiveness and acceptability are optimal.
Recapitulation of the phase 2 characteristics
Phase 3 of the deployment: extension of the dedicated lanes and equipment of the automobiles
The experience gained in phases 1 and 2 leads to the increase of the number of dedicated lanes and with the progressive equipment of the totality of cars. The number of automatic vehicles in circulation increased and it thus becomes possible to hold more road space for them (operation facilitated by the fact that automation requires less road space than traditional driving). Maximum speed in automatic mode can be increased and becomes compatible with long travels. The active safety systems necessary for automation equip all the new vehicles. The passive safety devices installed in all the new vehicles during the second phase equip all the vehicles from this stage.
Lastly, the optimisation of the traffic control becomes possible on certain critical axes. Some infrastructure managers practises a total control of the sub-networks reserved for the automatic vehicles. Insertion on the automated ways is always manual as well as the exits. However, thanks to the reduction of the reaction times and to total control, the throughputs of the automated lanes reach the level of the best "manual lanes" (2200 v/h) and thus higher than the currently noted flows. The profits obtained in terms of travel time and predictability are sufficient to attract towards the complete automation the users hitherto not very interested.
Recapitulation of the Phase 3 characteristics
Phase 4 of the deployment: generalization
All new infrastructures are dedicated to automated control. This is allowed due to the fact that the vehicles are equipped at " factory exit " with the safety and control required devices.
Compared to the former phase, new functions appear associated with a larger co-operation between the vehicles themselves (shorter intervals) and between the vehicles and the infrastructure. In the vehicles, these new functions relate mainly to automation at the entrances and exits of the network.
The most important modifications relate to the infrastructure. In order to guarantee free flow and travel time, the precise control of the whole network emerges in phase 4 since the entry of the vehicles to their exit. The principal functions introduced relate to the total control of the system, the determination of the parameters of control of each segment (speed, flow to be admitted on the entry in the segment), the determination of the parameters to be transmitted to the vehicles entering on each segment (instructions regarding individual intervals and speeds).
Although they can emerge on former levels, other functions are required in this phase. They relate for example to the measurement of the network state. It is indeed essential to constitute a map of automated traffic with an accuracy level probably higher than what is necessary on current networks or even on automated ways of the former phases (without automated insertion in particular). Other functions relate to the communications that allows data exchange (between the vehicles or with the infrastructure). One can also think that these networks constitute an important investment and their construction could be conditioned with a toll, which would require specific and complementary functions.
During this phase, one can also consider the upgrading of the existing motorways in automated motorways. Indeed, as soon as the number of equipped vehicles proves to be sufficient, certain equipped part of the infrastructure can be completely dedicated to automated driving. The question is here related to acceptance by the users of the induced transformations (e.g. the installation of toll on a free infrastructure of access - cf project TEO in Lyon - …). Improvement of the general conditions of circulation, continuity of the networks, reduction of the pressure on the environment, should be strong arguments supporting the development of the automated roads.
Characteristics of the phase 4
Other ways and other scenarios
The second phase of the presented scenario rely on introducing the dedicated lanes. This is justified by the need for accelerating the diffusion of automation and by adding the argument of mobility to the one of comfort. It is possible that the success met by automation was such that this type of decision was useless. One could then consider a scenario where the automatic and manual vehicles coexist from the beginning to the end on the same network
until disappearance of the manual mode.
We decided to introduce automation in the situations of congestion in suburban areas. It is also possible to consider automation at higher speed on the interurban motorways. On the one hand the interurban motorways constitute a protected environment, easily controllable, which reduces the technical difficulties; in addition the argument of comfort suggested would be perhaps more convincing. The problem is here to ensure the safety at high speed.
One can also imagine a mixed scenario where the first phase is founded on the low speed suburban scenario and the second phase would encompass the extension to the interurban motorways.
Among the assumptions some can prove not checked. One can, in particular, wonder about the choice of the target market segment. The private car constitutes a vector of introduction of automation since one wishes to reach as soon as possible a market of mass justifying a lowering of the costs. At the same time another justification relates to the progressive reduction of the degraded driving situations. One could also think as development vectors the transit vehicles, station cars or trucks.
The automation could allow, at acceptable cost, to improve the service provide by transit vehicles. Required space is reduced compared to manual control. Density of the bus lane network could be increased. The benefits of reserved lanes, constitutes an argument in this direction.
Again thanks to the automation, one could think developing a system of clean, automatic vehicles, proposed in self-service mode that use partly the automated lanes. Automation is capable to introduce more safety (respecting a maximum speed, obligatory stop at intersections or pedestrian crossings…) and more effectiveness (reduced intervals).
On the other hand, trucks constitutes a realistic way of introduction for advanced technologies. The cost of the heavy vehicles is such that the additional equipment cost would be, proportionally, less than in the case of the light vehicles ; a scenario whose first phases would be devoted to the improvement of safety and efficiency by automating trucks deserves hence to be studied.
References
1. " La Route Automatisée, réflexions sur un mode de transport du futur " 1996. Ouvrage de synthèse INRETS, INRIA, ENSMP, ENPC éditée par l’INRIA
2. " AHS Scenarios tailored for the mobility and the networtks of the French context " 4th world ITS conference, Séoul, Nov 1998
3. " Automated vehicles in Cities , a first step toward the automated highway " M. Parent, J.M. Blosseville, Future Transportation Technology Conference, Costa Mesa, Californie, Aôut 11-13 1998
4. " Semi-automated vehicles : The transportation of the future ", World Conference on Transport Research, Anvers, juillet 1998
5. " Safety oriented suburban scenarios for the "Route automatisée"D. Koenig, F. Guichard, J.M. Blosseville, D. Aubert, INRETS, M. Goursat, C. Gomez, M. Parent, INRIA,C. Laurgeau, J. da cruz, ENMP, P.Y. Texier, LCPC, R. Darbera, B. Bory, ENPC, 5th world ITS conference, Toronto, Nov 1999