Is complete road safety possible?

Swedish car manufacturer Volvo is setting the bar extremely high for 2020. Not only does it, like the rest of the EU's automotive OEMs, have to comply the very strict exhaust emission targets, it has also set itself the target of being perhaps the safest car in the world. Its goal is that no occupants of a new Volvo from 2020 onward will be killed or seriously injured.

Volvo along with fellow Swedish firm Saab pioneered much of the early safety engineering work in the automotive industry and has a reputation for solidity and reliability. However, while passive safety systems such as side impact protection, airbags, and seatbelts aim to keep occupants safe once there has been a crash, it wants to move safety to being active systems, where the car takes action in avoiding a crash altogether. While this sounds a bit off putting, put in perspective it not a big a leap as you might think. While many are not in favour of having cars make decisions for them, the fact of the matter is that 90% of road accidents are put down to human error. And, many already rely on driver aids such as electronic stability control or traction control where the car is technically contravening with the driver is actually doing. The company has been doing a number of trials and research projects recently to evaluate systems to car to improve safety. One example is the development of a sensor that can recognise and detect if a driver is tired or distracted. The system uses a sensor mounted on the dashboard that monitors the direction a driver is looking, how open their eyes are, as well as their head position and angle. The technology is already installed in test vehicles and Volvo is also conducting research together with partners to identify effective methods for detecting tiredness and inattention. In tandem with the sensors to detect the drivers focus, it is being incorporated in to other systems such as lane keeping aids, collision warning with full auto brake and adaptive cruise control with queue assist. It means, Volvo is able to use this information to adjust the car according to a given situation. For example, the car will not stray out of a lane or get too close to the car in front when the driver is not paying attention through checking a phone, changing the radio station, or simple looking out the window. And more dramatically it would be able to detect if a driver fell asleep at the wheel, and then be able to keep the car from weaving out of a lane, stop it from hitting any cars in front and wake the driver. This could possible all happen in a fraction of a second, but could be the difference between a scare at the wheel, and a potentially devastating crash. "It will enable the driver to rely a bit more on their car, and know that it will help them when needed," says Per Landfors, engineer at Volvo Cars and project leader for driver support functions. "Since the car is able to detect if a driver is not paying attention, safety systems can be adapted more effectively. For example, the car's support systems can be activated later on if the driver is focused, and earlier if the driver's attention is directed elsewhere." The sensor uses small LEDs to illuminate the driver with infrared light, which is then monitored. The infrared light is just outside the wavelengths that the human eye can see, which means that the person behind the wheel doesn't notice any difference. By monitoring eye movements, the car would also be able to adjust both interior and exterior lighting to follow the direction in which the driver is looking. Measuring how alert a driver is, known more formally as Driver State Estimation, is a field that may be key to self-driving cars in the future and one in which sensors will play an important role. Any cars acting in such a way will need to be able to determine whether the driver is capable of taking control when the conditions for driving autonomously are no longer present. Moves toward autonomous vehicles have also featured in another research project by Volvo that saw magnets inserted in to the roadway to help cars determine an accurate on the road. The project has been financed in strategic co-operation with the Swedish Transport Administration and could act as a key enabler in the implementation of self-driving vehicles. Reliable and highly accurate positioning is one of the crucial issues in the development of self-driving cars and established positioning technologies such as GPS and cameras have limitations in certain conditions. However, integrated magnets would remain unaffected by physical obstacles and poor weather conditions. The research programme was designed to evaluate issues such as detection range, reliability, durability, cost and the impact on road maintenance. Jonas Ekmark, preventive safety leader at the Volvo Car Group says: "The magnets create an invisible 'railway' that literally paves the way for a positioning inaccuracy of less than 100mm. We have tested the technology at a variety of speeds and the results so far are promising. "Our aim is for the car to be able to handle the driving all by itself as accurate, reliable positioning is a necessary prerequisite for a self-driving car." Volvo is playing a leading role in a large-scale autonomous driving pilot project in which 100 self-driving Volvo cars will use public roads in everyday driving conditions around the Swedish city of Gothenburg. "It is fully possible to implement autonomous vehicles without changes to the present infrastructure," says Ekmark. "However, this technology adds interesting possibilities, such as complementing road markings with magnets." In parallel with the potential in the field of autonomous driving, road-integrated magnets open up a number of other possibilities when integrated with safety systems, such as preventive run-off. In addition magnets could facilitate accuracy of winter road maintenance, which in turn could prevent damage to snow-covered objects, such as barriers and signs, near the road edge. There is also a possibility of more efficient utilisation of road space since accurate positioning could allow lanes to be narrower. The team has created a 100m long test track at the company's Swedish testing facility where a pattern of round ferrite magnets approximately 40x15mm wwere located 200mm below the road surface. The car was equipped with several magnetic field sensors and trials continue to be carried out. "Our experience is that ferrite magnets are an efficient, reliable and relatively cheap solution, both when it comes to the infrastructure and on-board sensor technology," says Ekmark. "The next step is to conduct tests in real-life traffic." Sensor development is also happening at tier1 component supplier Bosch, which is rising to the challenge of smarter and more accurate vehicle sensors. Its latest generation of acceleration and inertial sensors are allowing the further development of both active and passive safety systems, such as airbags and driver assistance systems. Its SMA6xy acceleration sensor platform simplifies the release approval process by giving sensors a common housing design whatever the application. In addition its SMI7xy inertial sensor platform is designed specifically for use in active and passive safety systems and in driver assistance systems. In addition to the normal x- and y- channels, these sensors are available with a z-channel for measuring acceleration in the vertical axis. This allows it to detect and react if a vehicle is about to rollover. The flexibility of the sensors gives airbag system developers greater design freedom than in the past. The sensors can register high accelerations of up to 35g and are ideal for use in electronic stability control programmes and other demanding vehicle dynamics applications such as hill hold control, adaptive cruise control, and active front steering. They also protect against microcuts, the extremely brief interruptions in power supply following an impact