In-vehicle anti-collision systems continue to evolve and could eliminate some incidents altogether. John Kendall rounds up the current developments.
A few weeks ago, I watched a driver reverse a car from a parking bay at right angles to the road, straight into a car driving along the road. The accident happened at walking pace, no-one was hurt and both cars had body panels that regain their shape after a low speed shunt.
While the driver should have been paying more attention or reverse parked, this type of accident could be virtually eliminated by technology within a few years by a proliferation of in-vehicle safety systems.
In that particular case a cross-traffic alert system could have helped prevent the accident. The system uses radar sensors to sweep the area to the rear and sides of the car during reversing manoeuvres and senses vehicles and objects approaching the car up to a range of around 30m.
If a vehicle is approaching the reversing car the reversing driver is alerted by an audible warning and signs on the dashboard. Current systems can only detect vehicles.
Radar sensors
Radar sensors are also used for the blind spot monitoring systems that have become widely available on cars in the past few years. These sense when a vehicle is in the blind spot around the rear quarters of the car where vehicles may not be visible in the driver’s mirrors. A warning light is usually illuminated in the relevant rear-view mirror (for cross traffic alert) or door mirror to warn the driver not to change lanes. This can help to prevent collisions during dual carriageway overtaking or motorway lane changing and is available from car manufacturers including
The next obvious step would be to detect smaller objects, such as pedestrians and cyclists, a function reversing sensors already perform when reverse gear is selected. A further step would be integration with the vehicle braking so that if the driver fails to react to an approaching vehicle or object, the system would brake automatically to avoid an impact.
Such a system, known as autonomous emergency braking (AEB), is already fitted to the front of the latest Volvo XC90 seven-seat SUV model. While systems which detect potential collisions with vehicles and objects ahead have been available for several years, the Volvo system has been designed to operate in low light conditions, by using sensing cameras with higher sensitivity and a faster response time.
Volvo’s stated philosophy is that by 2020 no-one should be killed or injured in a new Volvo car. Its latest XC90 is currently the standard setter for car safety systems and comes with established technology such as electronic stability control (ESC), blind spot monitoring, adaptive cruise control (ACC) and lane departure warning (LDW). But integration with other systems on the car has extended the capabilities offered, notably by having the functionality to intervene if the driver does not react.
Volvo claims a world first in fitting Run-off Road protection. Half the traffic fatalities in the United States are caused by a single vehicle leaving the road. According to the company, in Sweden one-third of all fatal and severe injury crashes involve a single vehicle. Its latest technology does not prevent such crashes but the system limits the injuries front seat occupants’ are likely to suffer. Volvo calls this Safe Positioning.
If the system detects the circumstances indicating the car might be involved an off-road incident, it automatically tightens the front seat safety belts until the car stops moving. In addition, the seats have been designed to minimise spinal injuries by increasing the energy absorbing potential between the seat and the seat frame. If the car makes a hard landing, the seat design is said to be able to reduce vertical forces on the occupant by up to one-third, helping to reduce the severity of spinal injuries.
Automatic braking
Volvo claims another world first in fitting the XC90 with a system that automatically applies the brakes if the driver turns in front of an oncoming car at a crossroads. The system is designed to operate in low speed crossings such as in city traffic or at higher speeds at a wide intersection.
This system is a development of autonomous emergency braking (AEB) and ESC (in which yaw sensors detect possible loss of control and the system can brake wheels individually to bring the car back under control). AEB can bring the car to a controlled halt under emergency braking, if the driver does not apply the brakes. New cars sold in the EU cannot obtain a five-star Euro NCAP rating without AEB. While the system does not need to be fitted to every new car sold, it must be available as an option on a model to obtain the five-star rating.
This type of system will be mandatory on new heavy trucks sold in Europe from 1 November 2015. Although car manufacturers are not yet obliged to fit it, it is hoped that the Euro NCAP move will persuade manufacturers to offer the system.
These systems use radar or lidar (light detection and ranging) sensors at the front of the vehicle, often paired with stereo video cameras mounted either behind the rear-view mirror or high on the windscreen for heavier vehicles. They sense the object ahead and its distance from the vehicle while an electronic control unit determines when to intervene by braking and reducing power, if the driver does not respond to the audible and visual warnings.
Lane Departure Warning
The EU has also made Lane Departure Warning (LDW) systems mandatory on heavy vehicles from November 2015. These systems use video cameras to monitor the vehicle’s position relative to the lane lines and warn the driver if it is straying out of its lane. Warnings include audible rumble signals or applying steering torque through the wheel to alert the driver to steer back into the lane. Crashes during lane changing are potentially serious but the risks are greater for large vehicles of up to 18.75m in length where it is easy for the driver to overlook a car or motorcycle along the side of a truck. Exacerbating this problem is by the mix of left- and right-hand drive vehicles sharing the same road space as this means truck drivers are effectively on the ‘wrong’ side of the cab. This can pose difficulties in seeing a car alongside their vehicle during lane change manoeuvres. Electronically monitoring this blind spot should help to reduce lane change collisions.
The size of trucks also obscure car driver’s vision which is particularly important when car drivers are considering overtaking a truck on a single carriageway per direction road. In Argentina this scenario has led to many crashes and prompted
Another advantage claimed for the Safety Truck is reducing the crash risk caused by the truck braking suddenly to avoid hitting crossing animals.
Currently, the prototype truck has passed the testing phase and Samsung has proved the technology works and that this idea can save lives. The next step is to test compliance with the national protocols and obtain the necessary permits and approvals.
Active safety systems
The introduction of active safety systems, such as AEB, where the system does not just alert the driver to potential accidents but intervenes to take avoiding action, has advanced safety systems in recent years. Another feature available on the Volvo XC90 is Queue Assist. This not only combines the car’s autonomous cruise control, AEB and lane departure warning systems, but it can also take active control of the steering. In queueing traffic, which may constantly advance a short distance at low speed, then stop, the XC90 can carry out this function automatically, accelerating the car, slowing it to a stop and keeping it in lane without input from the driver.
BMW’s Mini sub-brand displayed a new safety concept based on a head-up display (HUD) technology at the Auto Shanghai Show in April. Instead of projecting information onto a screen or the vehicle’s windscreen, a small unit projects it onto the lens of a pair of spectacles worn by the driver.
Information such as navigation data and speed are projected onto the lens within the wearer’s field of view.
From a safety perspective, claims that the system provides a method of ‘seeing’ through the car’s A-pillar could help to reduce accidents involving pedestrians, cyclists and motorcyclists as well as with other cars.
Vehicle A-pillars have become progressively thicker to increase protection of occupants in frontal impacts and rollover accidents. As a consequence, it has become all too easy for pedestrians, cyclists and motorcyclists to be obscured by the A-pillar, particularly where the car and object have a similar closing speed.
The system uses a wireless connection to the car to gather the necessary information from onboard cameras, sensors and other systems.
As displayed, the system capabilities included augmented parking. A camera in the nearside mirror housing relays images to the spectacle screen to improve the driver’s view of the kerbside while parking, which could help to alert the driver to nearby pedestrians.
An obvious drawback is the need for the driver to wear spectacles that could prove problematic for existing spectacle wearers, but the prototype system could be an indication of future HUD developments. The new Volvo XC90 features a HUD system that projects directly on to the windscreen and arguably a system with two or more projectors could replicate the capabilities of the Mini system without the need to wear the spectacles.
Motorcycle braking
Using sensors with an onboard control system, the new system apportions front/rear braking to maintain stability while the motorcycle is leaning over. Roll and pitch rates as well as lateral acceleration are monitored and the brake pressure applied in a more gradual way than with a conventional ABS system, meaning the rider is less likely to fall off while simultaneously cornering and applying heavy braking.
Onboard safety systems have evolved from driver control to offering limited intervention when loss of control seems likely, to predictive systems which take preemptive action to prevent the loss of control. More can be done, as Continental Automotive demonstrated at this year’s Consumer Electronics Show in Las Vegas.
A version of its dynamic eHorizon has already been trialled in
So it seems in terms of safety systems, the line between driver aids and full autonomy gets ever thinner.
