On 7 May 2016, Joshua Brown died on a Florida state highway in a Tesla Model S that was running in Autopilot mode. The ill-fated Tesla fan will go down in history as the first victim of a self-driving car error or, to be more precise, the first victim of the limitations of the car’s embedded sensors. Investigations have revealed that very bright sunlight prevented the car’s embedded camera from detecting a white tractor-trailer crossing the road slowly in front of his car as it was travelling at a brisk pace along the road. Current improvements to sensors and software are likely to improve the reliability of autonomous driving systems, but road infrastructure and even other vehicles on the road will also have a role to play in enhancing road safety. For example, if a surveillance camera on the highway had automatically detected that the tractor-trailer had stopped, or if the nearby vehicles had been able to transmit this vital information to the Tesla, Joshua Brown’s life might have been saved.

Using WiFi for vehicle-to-infrastructure communications

Back in the last century, the United States had already begun working on network protocols to enable vehicles to communicate with infrastructure. Since then, V2X (Vehicle-to-Everything) communications standards have gradually emerged. V2X is a special WiFi system that allows a set of traffic lights to communicate with nearby cars and can enable a vehicle to warn all those following behind when there is an obstacle on the road. A number of research centres are currently carrying out experiments in this field. While network configurations have now been standardised, it still remains to standardise all the messages to be exchanged between vehicles and infrastructure.


Mcity: an experimental "lab" to test V2V communications

For example, Mcity – a 32-acre simulated urban and suburban environment that includes a network of roads with intersections, traffic signs and signals, streetlights, building facades, sidewalks and construction obstacles built by the University of Michigan – and Transpolis in France have been created precisely to test message exchanges in near real-life conditions. "The mission of Transpolis is to drive advances in infrastructure, in preparation for the advent of self-driving vehicles," explains Stéphane Barbier, Chief Business Development Officer at Transpolis Smart City/Urban Mobility Lab. The project leaders are planning to build a 198-acre city for testing cooperation between connected self-driving cars. Barbier underlines: "We must keep in mind that a vehicle is only one component of a mobility system that includes infrastructure, with road-embedded sensors, communicating traffic lights, power systems and communications networks." Such pilot installations enable the technological robustness of solutions provided by auto manufacturers to be tested, along with their interoperability with basic infrastructure and other vehicles’ systems.

In addition to the tests being carried out in a protected environment, many other projects in Europe, the United States and Asia are now trialling ‘cooperative’ infrastructure. In France the SCOOP@F project, now already in its second phase, is a huge pilot project intended to connect around 3,000 vehicles with some 2,000 kilometres of road. Launched by the French Ministry of Ecology, Energy, Sustainable Development and Spatial Planning in 2014, the initiative is co-financed by European Union research funds. 

Among the participants in this large-scale pilot project are the ‘Direction des routes en Ile-de-France (DiRIF)’ – the body that manages the road network in the Greater Paris region – and SANEF, a motorway operator company in the north and east of France. These two road network management companies are closely involved in the venture. DiRIF is going to install a communication box every three kilometres along a 300 kilometre stretch of road, while SANEF will equip the 400 kilometres of the A4 motorway between Paris and Strasbourg. The purpose of these installations is first and foremost to aid emergency response vehicles but meanwhile they will also help to gather a huge amount of information with a view to perfecting ‘cooperative’ roads.

Other Co-operative Traffic Systems projects in Europe include a corridor between Rotterdam, Frankfurt-am-Main and Vienna, and NordicWay, a pilot project designed to enable vehicles to send out alerts on safety hazards via cellular networks on a road corridor running through Finland, Norway, Sweden and Denmark. In parallel with these major international initiatives, Audi of America, which owns and operates Audi brand car dealerships in the United States, has not waited for researchers to complete their work on standardisation before offering what it calls the ‘V2I’ service in high-end Audi vehicles. The new system was unveiled in Las Vegas in late 2016 and is due to be rolled out in a number of other US cities this year. In the absence of direct sensor-based communication between road and vehicle, the German automaker has come up with a pragmatic, efficient solution. The system collects traffic light information from the city’s control centre. This data is then transferred to the Audi telematics centre which transmits information to its vehicles via the LTE (4G) cellular network.

Roads as a future source of data

In the medium-term future, roads will be embedded with sensors that will help to improve road safety. "Road signage with for example ‘smart’ display panels or even sensors helping to guide vehicles," predicts Adel Ghazel, a university lecturer in Telecommunications and Head of Innovation at Consulting and Systems Integration company Wevioo, explaining: "These sensors will add a dynamic dimension to mapping functionality. They’ll be integrated into the surface of the road so as to detect the passage of traffic in real time. This information will be made available to all nearby vehicles, whether for the purpose of regulating the traffic or sending an alert when an accident has occurred.” 

However, the first such sensors will not be embedded in the road, but installed above it. The surveillance cameras that are already installed along motorways and urban road networks could well be used as a data source, points out Didier Blocus, Head of New Mobility at French fleet management and car leasing company ALD Automotive: “Security cameras can send out an alert when a vehicle is travelling in the wrong direction, or if a car has stopped in the emergency lane. Image analysis software can signal this type of event immediately and can also warn of the presence of a pedestrian or an animal on the road.

In order to free ourselves from the constraints which are today hindering the development of autonomous cars, roads will have to be adapted to suit such vehicles.
Adel Ghazel

Adel Ghazel

This solution has the great advantage of being able to use equipment that has already been installed at the roadside, but in order to gather data on self-driving behaviour to feed into algorithms, road infrastructure operating companies will have to go well beyond that and install sensors and other connected devices in the actual road surface. Adel Ghazel argues: “In order to free ourselves from the constraints which are today hindering the development of autonomous cars, roads will have to be adapted to suit such vehicles. Having ‘smarter’ roads will ease the complexity of the car-embedded systems. Developing smart roads means we’ll be able to make the transition from the age of the automated vehicle to that of the truly autonomous vehicle."

New generation of communicating sensors now on the market

Arnaud de la Fortelle, Head of the Robotics Centre at the prestigious École nationale supérieure des mines in Paris (aka Mines ParisTech), who is conducting research in this field, underlines that there is nothing new about placing sensors along the road in order to guide self-driving vehicles. “Guide wires, a technique which simply involves embedding an electric wire in a pathway is already in widespread use, including on many golf courses! The first driverless cars in Europe were based on this technology – some twenty years ago,” he points out, adding: “Nowadays we’re able to do a lot better because we can map areas down to the last centimetre.“ 

With their Lidar tele-detectors, the current generation of self-driving cars are able to geolocate themselves in their environment without the aid of road-embedded sensors, but if we want to increase the safety levels of AVs we will have to feed their algorithms with data that the vehicle’s sensors cannot access themselves: patches of ice, an obstacle hidden around a corner, etc. Only the road itself can communicate this type of information, but moves to place connected sensors in the road nevertheless pose some real challenges to the designers. For instance, the lifetime of the device will have to match that of the road surface or the infrastructure in which it will be embedded and an adequate power supply will have to be provided. Not least, engineers will have to produce sensors with a unit cost compatible with very large-scale deployment.

Hikob uses sensors to make the road smarter
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One of the firms working on developing a new generation of sensors is French startup Hikob. The company has developed a range of wireless magnetometer sensors designed to detect vehicles in car parks and also on the roads so as to help improve traffic flows. Hikob has also designed a temperature sensor which lasts longer than ten years. Reveals Ludovic Broquereau, Hikob’s VP for Marketing & Business Development: “We’ve produced temperature sensors for the roads in the Greater Lyon area. They help predict frost and the formation of ice so as to trigger salt-spreading operations in and around the city.” Up to now, such sensors required cables to be laid in the road to provide electric power and gather data into a control point, and these constraints have severely limited the large-scale deployment of these sensors. 

The advent of components from the smartphone world, which consume very little power, and the widespread use of wireless communication solutions, are gradually removing these constraints. The sensors developed by Hikob relay their data to a radio box at the side of the road which is powered by a battery and a small solar panel. For the time being, given that we have not yet reached a critical mass of vehicles fitted with V2X boxes, infrastructure operators collect only data intended for their control centre, but Ludovic Broquereau believes that it will certainly be possible to relay messages directly to vehicles from motorway bridges simply by incorporating an adapted version of their V21 equipment into the system.

Soon there will be sensors in the tarmac!

Hikob is also working in conjunction with Vicat, France’s number three producer of cement, aggregates and concrete, which is looking to develop connected concrete, known in the industry as ‘functionalised’ concrete. This new approach enables sensors to be incorporated into the surfaces of motorways, viaducts and tunnels so as to monitor their physio-chemical properties throughout their lifetime and thus optimise maintenance schedules. Vicat is now placing Hikob’s magnetic sensors into roads. Ludovic Casabiel, who is in charge of public sector contracts and technical products at Vicat, reveals: “We carried out an initial test with Hikob to verify that their sensors would communicate properly once embedded in the asphalt. We installed the sensors at the gates of one of our factories and they were able to recognise the electromagnetic signature of each of our vehicles!

hiding the sensors inside the concrete

Soon the sensors will be inside the concrete

The sensors will therefore not only be able to provide traffic information but even indicate the types of vehicles passing a T-junction at any moment. A critical point here, for Vicat and its competitors, is to be able to guarantee the autonomy of the sensors. Casabiel stresses: “Our concrete has a lifetime of over 50 years and can sometimes last for a hundred so we’d have to produce sensors that can go on working for that sort of time period. That looks very unlikely at the moment but we firmly believe that the researchers will get there eventually. For instance, there already exist sensors that can automatically re-charge from vibrations around them; that’s one possible solution.” Whether the answer will be to use ultra-low-consumption sensors that re-charge from road vibrations or to equip them with micro-solar panels, the ball is now in the court of the engineers to come up with sensors that combine the need for long life, reliability and low-cost production.

Recharging electric vehicles on the go

Meanwhile the world’s leading road construction specialist Colas has turned the ever-present issue of how to power smart roads on its head. With its Wattway technology, the French civil engineering firm has turned stretches of highway into a giant solar panel. Explains Christophe Liénard, Director for Equipment and Innovation at the Colas Group: “Developing the ‘road of the future’ is one of the six major areas of innovation at Colas. We’ve started out with our Wattway product, which enables electricity to be generated from the road surface. It’s now a given that the vehicles of the future will be increasingly electric-powered and autonomous vehicles will be mainly electric. That’s why we’re now working on wireless re-charging and also on turning the road into a storage battery." 

Combining a power-generating road surface with magnetic induction loops for recharging the motor would certainly appear to be the most elegant solution to the autonomy issue for electric vehicles. However, the cost of the prototype of this ‘solar road’ – in the order of €5 million to lay just one kilometre – would seem to rule out large-scale deployment. Scania and Siemens have begun to test a less ambitious but perhaps more pragmatic solution. Their eHighway system deployed near the German capital Berlin and in Sweden supplies hybrid freight lorries via pantographs, a proven technique used on the railways. This solution is only suited to heavy goods vehicles as the system does not allow road speeds above a maximum of 56 miles per hour.

Charging cars through solar road energy



Whether we are talking about pantographs, induction loops embedded in the asphalt or ‘solar roads’, the economic logic of deploying such solutions on a country-wide scale is extremely difficult to determine. A study carried out by UK motorway and main highway operator HighwaysEngland put the cost of building a recharging lane for electric vehicles on the main English transit arteries, the M1, M20 and M6 motorways, at between €400,000 and €500,000 per kilometre. Over a period of 20 years, the total cost of the special lane would work out at some €20 million, 30% for construction and maintenance and 70% for the electricity needed to create the electromagnetic charging effect. If this vision is to become reality, this cost would have to be shared somehow between governments, operating companies and road users. 

With all the smart sensors, communications equipment and power transfer systems, the highway of the future looks set to be a piece of hi-tech infrastructure. However, while such advanced infrastructure is likely to have a highly positive impact in terms of encouraging the use of autonomous electric vehicles that will help reduce emissions of CO2 and pollutant substances from combustion engines, governments will have to think hard about how to recoup such heavy investments, which will have the further effect of diminishing the considerable tax receipts they currently reap on petroleum products. This may be the price to pay if we are to move towards zero risk and zero pollution on our roads.

By Alain Clapaud
Independent journalist specialising in the new technologies