SARTRE: Are Road Trains the Future?

Imagine cars that can drive themselves, that instinctively know the shortest route, the most efficient and safest driving conditions, saving time, fuel and energy. One project in Europe – the Safe Road Trains for the Environment (SARTRE) project – could be about to see this all become a reality within years, and, if everything goes according to plan, change motorway commuting forever.

Part-funded under the EU’s Framework 7 programme, this ambitious EU initiative is exploring the potential of a new concept that promises to cut fuel consumption, shorten journey times and improve traffic flow – all without the need for extensive changes to road infrastructure.

Taking up the challenge is a Ricardo UK-led collaboration which reads like a roll call of some of Europe’s finest: Germany’s Institut für Kraftfahrwesen Aachen, Idiada and Robotiker-Tecnalia of Spain, and from Sweden, the SP Technical Research Institute, Volvo Car Corporation and Volvo Technology. As Ricardo’s project coordinator Tom Robinson explains, it is a team that represents a unique mix of technologies, skills and expertise from European industry and academia.

The idea of road trains – a convoy of six or eight vehicles travelling along the highway in close proximity to each other – is not a new one. Achieving this dream of faster, safer and ultimately greener long-distance car journeys in practice, however, has previously always foundered on the cost and inconvenience of overhauling existing road networks to make it possible.

Wiring up miles of motorway with all the sensor and transmitter systems required would be a herculean task – not to mention a prohibitively expensive one.

Now, by focusing on in-car systems and utilising already familiar component technologies such as GPS, sat-nav and Wi-Fi, SARTRE aims, in Robinson’s words, to “introduce a step change in transport methods”. In principle, it could hardly be simpler. At the head of each road train – or “platoon” – is a lead vehicle, driven by a professional operator who is thoroughly familiar with the particular route. Drivers travelling on the same carriageway are alerted to the presence and destination of the train via their own vehicles’ navigation system and those wishing to join, signal their intent and enter the platoon envelope, surrendering control and being brought into tight formation to reduce drag.

Once firmly embedded in the road train, commuters will then be free to make use of their journey time however they wished – working, reading or simply watching TV. Then, as drivers near their desired location, they again signal to the lead vehicle, a larger gap is opened up and independent control is returned to enable them to leave the road train safely and continue to their destination in the conventional way.

Adapting technology for the road train

While it may be a simple enough notion, successfully realising it will inevitably hinge on the underpinning technology – and therein lays one of the project’s greatest potential strengths. Dr Erik Coeling, technical director of active safety functions at Volvo Cars, says, “this type of autonomous driving actually doesn’t require any hocus-pocus technology, and no investment in infrastructure. Instead, the emphasis is on development and on adapting technology that is already in existence.”

The team is looking at off-the-shelf components to provide each vehicle with its own autonomous driving control and software monitoring system, within a platoon-wide sensor envelope capable of collecting and collating all the individual inputs. In many respects this is the logical extension of the long-standing research drive within the automotive industry towards developing active safety systems such as traction control, ABS and braking assistance. Moreover, in the light of wider innovations across a broad range of vehicle-based applications, perhaps most notably in the defence and mining sectors, the whole concept of autonomous driving has now moved from the realms of science fiction and firmly into reality.

The requisite technology to control acceleration, braking and steering in the way demanded by the platoon paradigm is already here, but clearly adapting and integrating it will be the key and the clock is ticking. SARTRE began formally in September 2009 and is to run for three years, with the first vehicles equipped with prototype platooning systems expected to be running on test tracks in the UK, Spain and Sweden sometime in 2011. There are also plans to conduct trials on public roads in Spain before the project ends.

Gaining acceptance for road trains

Getting the idea up and running on Europe’s highways for real, however, calls for more than just robust technology; in the end, it requires public acceptance. There are many benefits to incentivise it and Coeling has described it as sounding like Utopia, but there are obvious concerns too.

Clearly, unless you have absolutely no imagination at all, taking your hands off the steering wheel of a car speeding along inches away from someone else’s back bumper for the first time will require a never-to-be-forgotten leap of faith, but of course the safety angle will have been well covered. Circumventing driver error to reduce accidents does, after all, form one of the project’s central objectives. None of that will win over the confirmed technophobes or the neo-Luddites, but most drivers, while perhaps not entirely comfortable with the all-pervasive creep of technology into everyday life, are at least familiar enough with it in respect of their cars not to be overly worried.

The promise of reduced fuel usage will make a powerful argument from both an economic and environmental standpoint, especially if it does amount to the 20% predicted. So too will the prospect of better use of the existing road capacity, particularly if this results in shorter and more predictable journey times, while freeing up the hours spent sitting in traffic for other, more productive uses also has clear appeal. There is even the possibility of commercialising the idea into a service business in its own right with users paying for the privilege of joining the platoon, bringing attendant benefits to the local economy.

Perhaps one of the most important factors in promoting acceptance will simply be ensuring that drivers feel comfortable. Although road trains are primarily seen as relevant to commuters travelling large distances by motorway on a daily basis, the idea also holds potential benefits for coaches, lorries and other types of commercial traffic. Finding a way to organise “mixed” platoons to make everyone feel secure will be essential; as Robinson puts it, “car drivers do not want to be between trucks”.

One thing is for certain, if the project does ultimately prove as successful as the research partners hope, motorway travel will never be quite the same again.