Cars In The Future : Specific Active Safety Devices
Return to Cars In The FutureContents of this section
- Antilock Braking Systems (ABS)
- Electronic Stability Control (ESC)
- Brake Assist
- Adaptive Cruise Control
- Lane Keeping and Adaptive Steering
- In-Vehicle Driver Monitoring
- Alcohol Ignition Interlock
Antilock Braking Systems (ABS)
Antilock Braking Systems (ABS) is a form of electronic braking which was invented to help a driver control a vehicle under heavy braking by preventing the wheels from locking up.
Although the ABS will not decrease a vehicle’s stopping distance compared to an identical vehicle without ABS, it ensures that the shortest distance in which a vehicle can be brought to rest is achieved. It is particularly effective in doing this on surfaces which are wet or icy upon which a vehicle is much more likely to skid.
Like every safety system, the effectiveness of ABS depends upon drivers knowing what the advantages of the system are, and being able to use them. One of the principal advantages of ABS is that drivers are able to steer whilst braking in order to avoid a collision. It is not always the case that drivers will take advantage of this ability.
This highlights the need for drivers to be fluent in how to interact with vehicle technology.
As ABS is the only active safety system that has had its effectiveness predicted before implementation, it gives a good chance to review how well this was achieved, which is looked at briefly in the ‘Introducing New Active Safety Safely’ section.
Electronic Stability Control (ESC)
Electronic Stability Control (ESC) is a further evolution of electronic braking technology such as ABS and also uses other systems such as traction control. It is intended as a way of correcting situations in which a driver has made an error by stabilising the vehicle quickly so as not to make any dangerous situations worse.
It will work in circumstances where steering is needed in order to turn the vehicle more effectively so as to provide a decreased risk of skid or loss of control.
One current hindrance to the spread of ESC onto a greater proportion of new vehicles is the shear number of names and trademarks associated with it. Consumers may not appreciate that a manufacturer offers a version of ESC on a vehicle from reading its literature, even though they may be aware of ESC and its benefits.
The following systems used by different manufacturers are equivalent to ESC,
- Active Stability Control (ASC)
- Dynamic Stability Control (DSC)
- Dynamic Stability and Traction Control (DSTC)
- Electronic Stability Program (ESP)
- Electronic Stability Program Plus (ESP+)
- Vehicle Dynamic Control (VDC)
- Vehicle Stability Assist (VSA)
- Vehicle Stability Control (VSC)
ESC has been the subject of a great number of published papers, each arriving at a different figure about what percentage of accidents it will prevent. It is important to judge each individual evaluation objectively. A paper predicting a high accident saving in countries with a different road environment may not be directly applicable in the UK.
A situational context under which the studies are carried out also needs to be examined when looking at the potential benefits of active safety, and the wide range of results for accident savings shows this.
There are a large number of ways of studying an active safety system (e.g. simulators, real world trials, statistical analysis post introduction of the system), environments that an experiment can take place in (e.g. rural or urban, different countries road networks) and for measuring the outcomes (e.g. speeds, different types of accident, driver behaviour, casualty reductions). Finally, in some studies, the prior social and situational context in which driving takes place in is not an examined variable.
There is one conclusion that all the papers reach however, no matter what debate may take over the exact percentage of accidents that ESC will prevent, it will be relatively significant, and out of all the technologies discussed in this paper, has the potential to make a measurable impact on the 2010 targets. It is important that the spread of ESC onto all vehicles should be encouraged.
The European Commission has proposed, as part of the CARS 21 program, that ESC is made mandatory . RoSPA would support this proposal, but will add that further evaluation on driver behaviour is required in order to produce ETP measures at the same time. This is to ensure that the best potential casualty savings from ESC are achieved.
Safer vehicle design to prevent skids needs to be encouraged along side of the introduction of ESC, as a large difference exists between the most and least stable of vehicles. ESC is a quick solution to increase a vehicle’s stability but it is not all that can be done. Setting standards that define an upper benchmark for a vehicle’s stability, and then rating individual vehicles against it, as part of a consumer information program, may be the best way to achieve progress in this area of primary safety.
One unique scheme working towards propagating the fitment of ESC is the Bosch ESP-rience (ESP is the trademark name for Bosch’s variant of ESC). This focuses on improving consumer awareness by improving the knowledge of the sales staff, which can then be directly passed on. Although no published evaluation has taken place, other than the monitoring of the fitment rate of ESC onto new cars.
This type of event should be evaluated in order to show if it can be viewed as good practice in helping the spread of a specific type of active safety that has been proven to have a large impact. In future, similar programs should be run showing what the technology does and giving a section of the population who can influence the public’s opinions and use (car sales people) a better grasp of the technology. An evaluation of the schemes impact will help road safety professionals understand more about how to help in this field.
Brake Assist (BA) is a technology that ensures that the maximum pressure is applied by the brakes to stop a vehicle in an emergency situation. Some manufacturers also refer to the same system as Emergency Brake Assist (EBA).
When a driver makes an emergency stop the brake pedal has to be pressed, the more pressure applied to the brake pedal, the greater the pressure through the braking system, which is amplified and provided to the brake. In some cases a driver might fail to respond to a hazard up ahead as well as possible and fail to depress the brake pedal fully, meaning that the full pressure of the braking system is not being applied to the wheels.
Brake Assist detects how quickly the pedal is depressed to judge whether the driver wanted to perform an emergency-braking manoeuvre. If it concludes that the situation is an emergency and the pedal isn’t depressed fully then it will increase the hydraulic pressure in the braking system to make up the gap.
It has been proposed by the EC that Brake Assist is fitted to all new vehicles as part of the new Regulations that require manufacturers to provide better front-end protection for pedestrians. This is part of a compromised deal, and the fitment of Brake Assist would mean less stringent safety standards. RoSPA are supportive of the introduction of Brake Assist on new vehicles, but stresses that active safety is not a substitute measure for an improvement in passive safety standards. The two are different methods of achieving injury reductions.
Adaptive cruise control (ACC) is a system designed to increase the comfort of a driver and is the first step towards Advanced Driver Assistance Systems (ADAS) reaching the vehicle fleet. It is comprised of radar technology that works in conjunction with the cruise control of vehicles. Whilst regular cruise control systems allow a driver to choose a speed which the vehicle maintains, adaptive cruise control monitors the distance to the vehicle in front, and will slow down the vehicle if necessary. The most modern versions of the system starting to appear on the upper end of the car market will stop the vehicle.
As cruise control is generally used on national speed limit non built-up A-roads, and motorways, this is where the current generation of ACC will be used. Like cruise control, it is a driver comfort system, although comfort and safety are interrelated and it will have an effect on safety depending on how it is used.
It will be mainly used when the road is congested and the driver has to apply the brakes to respond to the pulse like nature of the traffic flow. The current system will have an influence in safety and congestion, as well as driver comfort. The extent that it does depends upon the driver’s knowledge, attitude and behaviour. Ultimately, the driver still remains in control.
Adaptive cruise control also bears a precautionary message about driver comfort systems and active safety. It has been introduced without widespread trials that evaluate how it will be used in the real world context. Drivers could easily misuse a system, whether by accidental misunderstanding and assuming that the system is more effective than it is, or on purpose by relying on the system beyond its operational capacity. These issues must be looked into before a system is implemented, the potential use and misuse of a system will have an impact on safety – whether it is termed a comfort system or a safety system. There is no evidential link that shows that the category of a system would affect the way in which it is used.
One interesting study of Adaptive Cruise Control looked at the consumers awareness of the system and what they though of it before and after use.
The first interesting result was that 39% of the respondents had found out about the system in a sales brochure, 20% had heard about it from a sales person and 10% from a magazine article. This shows where consumers are likely to get information about vehicle technology, and similar studies in the UK may suggest how best to disseminate information about vehicle safety systems.
The study also concluded that consumers who chose to have ACC fitted were more likely to use the system to aid them during driving, showing a link between prior knowledge of the technology and a willingness to use it.
The development of ACC has lead to Stop and Go technology, which will automate the starting as well as the stopping (longitudinal control) of a vehicle depending on the vehicle in front.
Lane Keeping and Adaptive Steering
Lane Keeping and Adaptive Steering systems are the initial versions of ADAS designed to keep a vehicle in the correct lane position on the road.
Initial versions of this system monitor the lane markings by the side of the car, and if the car starts to deviate from the travelling lane, alerts the driver. The next generation of systems will be more proactive by applying torque to the steering wheel to encourage drivers to correct the drift. Eventually the system automation will itself prevent the vehicle from drifting out of lane.
In future, the systems can also be linked to blind spot information systems to prevent vehicles from moving into the path of another when a driver has not made the correct observations.
One element of active safety that may potentially bring accident reductions is when the vehicle monitors the driver’s state and performance for dangerous behaviour and practices.
Monitoring technology in a vehicle has many complex applications – such as monitoring a driver’s workload before deciding whether to give the driver useful but not crucial information – the most immediate to be realised will be in-vehicle systems, which detect the onset of driver fatigue.
Fatigue can be a highly dangerous impairment, and will result in the driver withdrawing and reducing the level of attention that they can dedicate towards maintaining appropriate levels of safety.
A recent study by the Sleep Research Centre at Loughborough University indicates that driver fatigue causes up to 20% of accidents on monotonous roads. This suggests that there are several thousand casualties each year in accidents caused by drivers falling asleep at the wheel.
A study of road accidents between 1987 -1992 found that sleep related accidents comprised 16% of all road accidents, and 23% of accidents on motorways. Research by the TRL found slightly lower proportions of sleep related accidents: 9%-10% of accidents on all roads, and 15% of accidents on motorways involved driver sleepiness. In this study, 29% of drivers reported having felt close to falling asleep at the wheel at least once in the previous twelve months.
The majority of the systems will monitor driver’s actions to detect to onset of fatigue, as there are many externally displayed signs which can be detected. It can be reasonable assessed whether someone has become less alert during an activity by judging where his or her attention lies.
In a vehicle, this reduction in alertness manifests itself by an individual item attracting a driver’s gaze and attention for a long period of time, the length of and period rate of a driver’s blink, and also the driver’s head position.
A human would be able to make an assessment of a driver’s concentration intuitively, or through experience, by looking at all of these factors. The challenge therefore lies to design a system that can also perform this task accurately.
The most researched method of doing this has been through a camera, which can provide an image of the driver. Software then works out what the camera is seeing (much like the interaction between the brain and the eye) and determines whether any of the indicators of fatigue are occurring.
The system would then work out what information to feedback to the driver, if it detects fatigue or drowsiness then a method of communicating this is required. Of course there is then the issue of how the machine would best output this information to alert the driver.
Finally, drivers would need to know what to do with the information that the system has given them. It would be of no benefit for the driver to know that they risk an accident due to fatigue if they do not know a suitable countermeasure for them to take, and many common practices that drivers will tend to do to keep themselves awake and alert are generally ineffective.
The only proven measures to reduce sleepiness in the short term are to drink at least 150 mg of caffeine and taking a short sleep of around 15 minutes.
However, this is only a temporary solution and the safest option is for drivers to avoid driving when sleepy, and it may also be worth the driver planning an overnight stop – again, technology could inform the driver of suitable places locally. The best way to combat sleepiness is to sleep.
There is also potential for vehicles to take a proactive, rather than reactive, role to preventing driver fatigue. The best technical solutions will warn drivers that they have planned a long journey which will take a significant length of time, and help them plan it to encompass breaks and overnight stays – helping to prevent fatigue from becoming a risk which the vehicle needs to detect the onset of.
Technology could also be used to monitor the hours that a driver has undertaken and maintain a record.
Drink driving continues to be a casualty problem in this country, although societal attitudes towards drink driving have changed significantly over the last 30 years, and the number of drink drive accidents has fallen. It still accounts for a large proportion of the fatalities and serious injuries from road accidents in this country. In the UK in 2004, it was estimated that there were 590 fatalities in accidents where a driver or rider had consumed an illegal amount of alcohol.
Worryingly, the number of fatalities from accidents involving illegal alcohol levels has been increasing since 1999.
Alcohol Ignition Interlocks (‘Alcolocks’) are a way of reducing the number of repeat offences of drivers who are convicted of drink driving, and may too have a role in preventing drink driving before an initial offence is committed.
An alcolock works by requiring a driver to pass a breath test before ignition, thus stopping a driver who is over the limit from starting the vehicle. Modern systems can prevent people from getting round the test by requiring further breath tests after ignition, and also by requiring users to hum, or breathe in after providing the test.
Alcolocks can either be implemented as a primary or secondary safety strategy. A primary accident prevention strategy would be the use of alcolocks in vehicles where there is no history of drink driving, and a secondary strategy is the provision of alcolocks as part of an offender’s rehabilitation.
The technology is already available for a primary strategy and one vehicle manufacturer has started to introduce the “alcokey” into some models as an additional extra, it is expected that the technology will be available in the UK soon.
There are clear benefits to a primary prevention strategy, especially if the vehicle is used for transporting high risk, hazardous, cargo – or indeed if the vehicle was a school bus or other public transport vehicle, and a primary strategy based on this is currently being trialed in Sweden. The technology may also help fleet operators control the level of risk posed by drink driving by fitting alcokeys to their fleet.
A secondary strategy is to offer alcolock use for drivers who have been convicted of drink driving – especially repeat offenders – as it will reduce the risk of them driving under the influence of alcohol with the alcolock in the car. A wide range of studies has shown that there is a large reduction in the likelihood of a convicted drink driver being convicted of the same offence again whilst an alcolock is installed, compared to convicted drink drivers without an alcolock.
A secondary strategy is starting to be introduced in the UK. Clauses 14 and 15 of the new Road Safety Bill will introduce the ability for courts to offer drink drive offenders the chance to partake in an “alcohol ignition interlock program”. This will comprise of a combination of education measures, along with the alcolock to give a combined approach to the problem.
The introduction of the alcolock will hopefully help participants to separate the acts of drinking, and driving, and increase the effectiveness of the educational messages – like all good road safety interventions, it is several measures working in unison towards the same outcome.
A strong case could be put forward for mandatory interlock use for some offenders based on the evidence that many who lose their license for driving under the influence continue to drive without it. It must be remembered though, that a users attitude towards the alcolock may also influence its effectiveness and also the chances of recidivism if the device is removed.
Criterion must be set for interlock removal, and the criterion must be proven indicators of a reduced repeat offence rate. As well as assessment by a psychologist, an alcolock can give a warning of future intent to drink drive, based on the number of, and frequency of, attempts to start a vehicle which have been prevented by an alcolock
There has not yet been a sufficiently large enough study to demonstrate the exact number of casualties that an interlock program may save. However, the risks of driving under the influence are well known and understood, as is the magnitude and increasing number of fatalities caused by it. If alcolocks can provide a way of reducing this risk and preventing drink driving, then it is fair to accept that their use will reduce the number of road casualties.
The relationship between alcolock use and potential casualty reduction needs to be determined, and from this a roadmap for an effective and evidence based, combined primary and secondary safety strategy could be produced.
It is also hoped that in future, devices may be developed to prevent drug driving.
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